www.stms.nlwww.stms.nl

• Rolling for recovery

• Meet the expert: Dr. Gary Windler

• Tennis training

• PRO U™ Player Orientation

• Best serving strategy

www.stms.nl

medicine and science in tennis

June 2008 • volume 13 • number 2

J o u r n a l o f S T M S i n c o - o p e r a t i o n w i t h : I T F • A T P • S o n y E r i c s s o n W T A T o u r

ChairMoroe BEPPU, MDCongress OrganizerChairman & ProfessorDepartment of Orthopedic SurgerySt. Marianna University School of MedicineKawasaki, Japan

Message from the President

2

Dear Members,

Babette Pluim, the founding and current editor of the STMS journal, has decided to step down after 13 years in offi ce so this will be the last STMS journal she is editing. Once again, this issue demon-strates the very high standard our journal has reached as a result of her tireless eff orts and we owe her a very big “Th ank You”!

Th is edition has several original articles in all disciplines of tennis medicine and science. Th ere are articles on the adoles-cent athlete, mental health and psychology, and optimisation of performance through the use of statistics. Th ere are medicine papers on imaging of os acromiale and the prevention of ankle sprains, both important topics as the fi rst is a bit of a controversial, but signifi cant issue, and the other due to the great frequency of ankle sprains in tennis. Th ere are tips for coaches, and information about what the professional players are learning, in the WTA article on the Players’ Pro University about professional life and life after tennis.

Continuing in the series of Meet the Expert, we have included an interview with Gary Windler, a member of the ATP Medical Team, clinician and active researcher of issues relating to the professional tennis player. Further, there are book and DVD reviews about tennis medicine and science to help our readership evaluate what they may want to use to further investigate areas of tennis medicine and science.

Lastly, a conference calendar of upcoming tennis related meetings (in addition to review of the most recent tennis science and technology meeting) is provided, including the two upcoming STMS meetings. Th ere is the North American Regional Meeting being held August 1-2, 2008 in Cincinnati during the ATP tournament and hosted by Neeru Jayanthi and Robert Rhoades. Additionally, the World Congress of the STMS will be held in Tokyo, Japan during October 2-4, 2008, hosted by Moroe Beppu. Th e world congress promises to be a fantastic meeting, with three concurrent sessions, including work shops for trainers, debate sessions, current concepts and some of the newest, exciting original research in tennis medicine.

Once again, many thanks to Babette for all her hard work over the last 13 years. Th e STMS Journal is a magnifi cent legacy of her ongoing eff orts to improve the delivery of sports medicine education to our tennis community.

I hope to see you in Cincinnati and Tokyo!

Sincerely,

Marc R. Safran, MDPresident STMS

ISSN: 1567-2352

Medicine and Science in Tennis is a Journal produced by the Society for Tennis Medicine and Science (STMS) in co-operation with the ITF, the ATP, and the Sony Ericsson WTA Tour, and is issued three times a year (February, June, and October). Medicine and Science inTennis is listed in Altis, Free Medical Journals, MedNets,NewJour, Sponet and SIRC Sports Discus.

Th e International Board of the STMS:President: Marc R. Safran, San Francisco, CA, USAE-mail: president@stms.nlVice-President: Javier Maquirriain, Buenos Aires, ArgentinaE-mail: vicepresident@stms.nlSecretary/Treasurer: Bill Durney, San Francisco, USAE-mail: info@stms.nlMembership Offi cer: Todd S. Ellenbecker, Scottsdale, AZ, USAE-mail: membership@stms.nlPast-Presidents: Babette M. Pluim, Ede, the NetherlandsPer A.F.H. Renström, Stockholm, SwedenW. Ben Kibler, Lexington, KY, USAAdditional Members: Peter Jokl, New Haven, CT, USABernard Montalvan, Paris, FranceAssociates to the Board: Miguel Crespo, Representative of the ITFKathy Martin, Representative of the Sony Ericsson WTA TourGary Windler, Representative of the ATPHonorary Members: Irving V. Glick, Great Neck, NY, USASavio L-Y Woo, Pittsburgh, PA, USA

North American Regional Committee:Chairman: Marc R. Safran, San Francisco, CA, USANeeru Jayanthi, Chicago, IL, USAPeter Jokl, New Haven, CT, USAW. Ben Kibler, Lexington, KY, USACarol Otis, Portland, OR, USAE. Paul Roetert, Key Biscayne, FL, USASavio L-Y Woo, Pittsburgh, PA, USA

European Regional Committee:Chairman: Giovanni di Giacomo, Rome, ItalyGilles Daubinet, Paris, FranceHans-Gerd Pieper, Essen, GermanyBabette Pluim, Ede, the NetherlandsAngel Ruiz-Cotorro, Barcelona, SpainMichael Turner, London, United Kingdom

South American Regional Committee:Chairman: Rogerio Teixeira Silva, São Paulo, BrazilJavier Maquirriain, Buenos Aires, Argentina

Scientifi c Committee:Chairman: J. Chandler, Jacksonville, AL, USABruce Elliott, Perth, AustraliaW. Ben Kibler, Lexington, KY, USAKarl Weber, Cologne, GermanySavio L-Y Woo, Pittsburgh, PA, USA

Educational Committee:Chairman: Neeru Jayanthi, Chicago, IL, USAPeter Jokl, New Haven, CT, USAW. Ben Kibler, Lexington, KY, USAKathy Martin, Melbourne, AustraliaPiotr Unierzyski, Poznan, PolandGary Windler, Summerville, SC, USA

Editorial Board:Editor-in-Chief: Babette M. Pluim, Ede, the NetherlandsE-mail: editor@stms.nlTodd S. Ellenbecker, Scottsdale, AZ, USANeeru Jayanthi, Chicago, IL, USAJavier Maquirriain, Buenos Aires, ArgentinaMaarten Moen, Amsterdam, the NetherlandsRogerio Teixeira Silva, São Paulo, BrazilBert J.G. van Weelde, Th e Hague, NetherlandsGary Windler, Summerville, SC, USA

Editorial Assistant:Anne Meredith, Wakefi eld, United Kingdom

Subscriptions and Membership:Todd S. EllenbeckerPhysiotherapy AssociatesScottsdale Sports ClinicScottsdale, AZ 85258, USAE-mail: membership@stms.nl

Annual Subscription fees due 1st January 2008Full membership: $175.00Student membership $100.00

Delegated Publisher:TopNautic MediaOnder de Bomen 76871 CG RenkumTh e NetherlandsPhone +31-317-350728E-mail h.dijkman@topnautic.nl

Design:Leon van Loon, Liessel, the NetherlandsE-mail: info@leonvanloon.nl

Cover photo:Maaike Smit, Emmeloord, Netherlands

Photography:Jeff and Manuela Davies, Orlando, FL, USAwww.doubleXposure.com

Circulation: 2,000

Webmaster:Vincent ter Maat, Wageningen, the NetherlandsE-mail: webmaster@stms.nl

Website:http://www.stms.nl

Disclaimer:Th is journal is published by the Society of Tennis Medicine andScience for general information only. Publication of information inthe journal does not constitute a representation or warranty thatthe information has been approved or tested by the STMS or thatit is suitable for general or particular use. Readers should not relayon any information in the journal and competent advice should beobtained about its suitability for any particular application.© 2008 Society of Tennis Medicine and Science.

All rights reserved. No part of this publication may be reproducedin any form without prior written permission of the copyright.holder. Opinions and research expressed in this journal are notnecessarily those of the STMS.

STMS is sponsored by:

Contents

2 Message from the President Marc R. Safran

4 Rolling for recovery Allistair McCaw

8 Physiological and behavioural responses to thermal stresses in tennis Sarah Morante

10 Introduction to PRO U™ Player Orientation Thomas Livengood, Ashley Keber and Kathy Martin

13 Tennis Training Enhancing on-court performance Mark Kovacs, Britt Chandler and Jeff Chandler

14 Imaging of sports-related muscle and tendon injuries in children and adolescents Evert J.L. Vandervliet, Filip M. Vanhoenacker, Annemiek Snoecks, Jan L. Gielen, Pieter van Dyck, and Paul M. Parizel

16 ITF hosts successful TST Congress

17 Conference calendar 2008

18 Preventing ankle sprains and improving balance in tennis players Vasiliki J. Malliou, Paraskevi Malliou, Asimenia Gioftsidou, Stavros Douvis and Alexandros Mavvidis

21 The Knee: Patient evaluation / Imaging / Therapy and Rehabilitation Rudolph Schabus and Elisabeth Bosina

22 Loading and velocity generation in the high performance tennis serve Machar Reid

24 Applying match statistics to increase serving performance Tristan Barnett, Denny Meyer and Graham Pollard

28 Australian elite tennis juniors’ perceptions of the importance of mental skills Janet A. Young

32 Meet the expert: Dr Gary Windler

34 What is the best serving strategy? Geoff Pollard

39 Core Stability Training on DVD Carl Petersen and Nina Nittinger

40 10th STMS World Congress

medicine and science in tennis

3

4

Rolling for

recovery How fast your body recovers from the previous match or training session can ultimately determine your next performance, because if your body has not been able to repair and regenerate sufficient-ly, you simply will not perform to your maximum potential.I am a firm believer in the saying “Your next performance is only as good as your recovery from the last”. With this in mind, recovery and regeneration are treated with as much importance in the programmes I set for my athletes as movement, nutrition and mindset.

Tennis is a physically demanding sport. Players can experience muscle restriction (feeling stiff ), which can alter joint motion and lead to poor movement patterns, a faster rate of fatigue and injury.

As a sports performance trainer working in tennis, I have discovered that the primary focus of many coaches and players is on training and competing, whilst recovery is often forgotten or given less attention. I often see athletes who put time and tre-mendous effort into their workouts, only to quickly rush through their cool down and stretching routines. They are missing one of the most important aspects of their pre-habilitation (preparing the body against injury) post performance body maintenance.

The best kept secret to maximising your perfor-

mance is simple: “Recover better” according to

tennis performance trainer Allistair McCaw. In this

article Alistair explains his views on the potential

benefits of using a simple piece of foam to optimise

recovery and recommends eight specific foam-

rolling exercises for players of all standards.

Allistair McCawMed Sci tennis 2008;13(2):4-7

C o a c h e s C o r n e r

Recovery is

probably one of

the most overlooked

aspects in an

athletes’ program

Having a programme that incorporates good post training/match recovery techniques is critical for a player’s overall development and performance. It enables the player to perform the next time with less fatigue and in doing so, adapt to workloads faster.

The most common techniques used by players today are sports massage, aquatic therapy (pool running, movement exercises etc.), yoga and stretching. These all definitely contribute to the healing process, but the problem is the time that lapses between the end of the training session and when the massage, aquatic therapy or yoga happens. So what would be the best way to bridge this important gap between training and taking care of the recovery? One suggestion is to have your athletes rolling on a foam roller the minute they finish their workout.

Why foam rolling?Hard exercise may lead to increased tension of our muscles and joints. Self-massage exercises (self-myofascial release) on this simple piece of foam can immediately reduce soft-tissue tension and speed up the recovery process. Using a foam roller can also provide similar benefits as a deep-tissue massage. By increasing flexibility and decreasing muscle tension, it can help to prevent injury, decrease muscle pain and improve function and perfor-mance. Your muscle resembles a rubber band and the further you stretch it, the further it will launch when you let it go. If you can increase the elasticity in the muscle by improving your flexibility, the result will be increased power and improved performance.

I believe that the foam roller is one of the most effective, all-around self-maintenance tools you will find, as it not only releases chronic muscular tension and pain (caused by playing or performing movement), but can actually restructure your skeletal system so that it aligns more positively with gravity. It is simple to use as you use your own body weight to roll on the round foam roll, massaging away restrictions to normal soft-tissue extensibil-ity. Foam rolling is like getting a massage without the expense of a massage therapist. In fact it’s like having your own physical therapist, chiropractor, and masseuse at your beck and call. How-ever, I definitely do not condone the services these practitioners offer as a good massage is always recommended.

5

There are many potential benefits of foam rolling - it • can prevent joint stiffness and possibly reduce injury risk• increases flexibility and joint function• speeds up the recovery process• is portable, light (weighs less than 500grams) and easy to travel

with• limits the costs of a regular massage

The better your

recovery the faster

your progress will be

Your turn!I have put eight exercises together specifically for tennis players. These exercises cover all the major muscle groups involved in the game. Make these exercises part of your regular cool-down routine. Perform them directly after your training session or match (after a cool-down jog or spin on bike, but before stretching) to maxi-mize their recovery time!

Place your body on the roller and slowly roll up and down (for about 30-45 seconds) along the muscle group you are targeting. I have a basic rule: If it hurts, it needs more attention. So if you find a particularly tight area, pause on that spot. Putting pressure on a tight area can help release the tissue.

Exercise 1. Iliotibial bandPosition yourself side lying on foam roll. Bottom leg is raised slightly off floor. Maintain head in ‘neutral’, with ears aligned with shoulders. Roll just below hip joint down the lateral thigh to the knee.

Exercise 2. Gluteal muscles Begin in position as shown with foot crossed to opposite knee. Roll on the posterior hip area. Increase the stretch by pulling the knee toward the opposite shoulder.

Exercise 6. AdductorsExtend the thigh and place foam roll in the groin region with body prone on the floor. Be cautious when rolling near the adductor complex origins at the pelvis.

6

Exercise 3. HamstringsPlace hamstring on the roll with hips unsupported. Opposite leg is bent to support this position. Roll from knee towards posterior hip while keeping quadriceps tightened.

Exercise 4. QuadricepsBody is positioned prone with quadriceps on foam roll. It is very important to maintain proper core control (abdominal drawn-in posi-tion and tight gluteal muscles) to prevent low back compensations. Roll from pelvic bone to knee, emphasizing the lateral thigh.

Exercise 5. CalvesPlace calf on the roll with hips supported. Have other knee bent to support a balanced position. Roll from below knee to Achilles tendon.

Tennis performance specialist Allistair McCaw is founder of Performance Tennis which specializes in tennis-specifi c conditioning training. Allistair has worked with no less than 6 top 20 tennis players including Jelena Dokic, Nathalie Dechy, Michaella Krajicek and Dinara Safi na. He has also trained the world numbers one and two squash players Nicol David (world champion) and Natalie Grinham. Address for correspondence www.performancetennis.com

Abou

t the

aut

hor

7

SummaryWhatever your level, foam rolling should be an integral part of your daily routine. It will aid injury prevention and recovery, and is one of the easiest and cheapest ways to improve recovery, allevi-ate aches and pains and improve fl exibility. Use the roller directly after your workout prior to your cool-down stretch and remem-ber that areas that hurt need more attention. A quicker recovery translates to a better performance the next time you play!

Exercise 7. Latissimus dorsiPosition yourself side lying with arm outstretched and foam roll placed in axillary area. Th umb is pointed up to pre-stretch the latissimus dorsi muscle. Movement during this technique is minimal.

Exercise 8. Upper backCross arms to the opposite shoul-der to clear the shoulder blades across the thoracic wall. While maintaining abdominal drawn-in position, raise hips until unsup-ported. Also stabilize the head in ‘neutral’. Roll mid-back area on the foam.

8

Physiological and behavioural responses to thermal stresses in tennis

Whilst environmental conditions within the prescriptive zone enable the maintenance of body core temperature, skin tempera-ture is hypothesized to rise with increasing ambient temperature up to approximately 36°C in order to maintain convective heat dissipation. Since the thermal gradient for convective heat loss is reduced as air temperature approaches skin temperature, with heat being gained when skin temperature exceeds air tempera-ture, the evaporation of sweat becomes the major if not sole method of heat dissipation. Therefore, sweat rate would be ex-pected to increase with ambient temperature in order to maintain thermal equilibrium. Whilst core body temperature is main-tained within tolerable levels during the prescriptive zone, players may subjectively rate conditions within the prescriptive zone as intolerable due to thermal discomfort that results from high core and skin temperatures and/or skin wettedness. In more stressful environmental conditions, or when players are experiencing physiological or subjective strain, players are expected to modify their behaviour to reduce the workload and heat production. This would be indicated by a reduction in effective playing time, point duration and stroke frequency. Within the prescriptive zone, it is anticipated that thermoregulatory responses will agree with previously published studies including: metabolic heat produc-tion of approximately 680 W, heart rate of around 145 beats.min-1; body core (rectal) temperature of around 38.2°C; and sweat rate of approximately 0.93 L.h-1. When conditions exceed the prescriptive zone, core body temperature is expected to be higher in response to the greater heat load that results in thermal equilibrium being achieved at a higher core body temperature. However, it is unknown whether the thermal environment and exercise intensity will represent a stress level above the upper threshold of the prescriptive zone during the experimental tennis matches within this study.

Methods: In the laboratory, the maximum aerobic power (VO2max) and body composition for each subject was assessed. Experimental tennis matches were completed by men and women of varying standards in a range of thermal environments. Each of the six thermal stresses (air temperature, humidity, solar radiation, air movement, clothing and metabolic heat produc-tion) were measured or predicted for each tennis match and player. A whirling psychrometer was used to measure dry bulb (air) temperature and wet bulb temperature (for humidity) at 20 minute intervals throughout each tennis match and player. Mean radiant temperature (for solar radiation) was assessed by a globe thermometer, which recorded globe temperature each minute throughout matches. Air movement was also logged each minute

Background: Tennis is played year-round throughout the world in a wide variety of weather conditions. Often players in the Australian Open, held in the middle of summer, are faced with air temperatures exceeding 40°C. The current Extreme Heat Policy used at the Australian Open postpones play at an absolute air temperature ≥ 35°C and a Wet Bulb Globe Temperature ≥ 28°C. This is based on the American College of Sports Medi-cine’s Exertional Heat Illness Policy for distance running. There-fore, this policy may be inappropriate for tennis where activity is interspersed with rest periods which reduce the overall exercise intensity. Furthermore, there has been no known scientific evaluation of this policy. However, a review of its applicability to tennis using the current information base is difficult since there is no objective information about the effects of environmental conditions on players’ physiological responses, comfort and behaviour. Tennis players of all levels would benefit from objec-tive and comprehensive information relating to how the thermal environment affects their health and safety, and comfort. Such information enables them to make decisions about whether they choose to play tennis on a given day, the duration and intensity at which they play, the required fluid replacement, strategies to manage thermal comfort (e.g. wetting the skin, moving to the shade or fanning), and tactical modifications. These decisions enable players to minimise the risk of developing heat illness, and maximise comfort in adverse weather conditions.

Research objectives: The aim of this thesis was to obtain com-prehensive data on environmental and metabolic heat stress, and body temperature regulation during competitive singles tennis matches over each of the seasons in Sydney, Australia. These data were then be used to determine whether a steady-state core body temperature and thermal comfort are being achieved in tennis, in addition to the mechanisms responsible for their attainment (i.e. autonomic / physiological thermoregulation or behavioural / psychological thermoregulation?). These data were also used for the rational analysis of heat stress, which will enable prediction of all thermal exchanges and thus, tolerable environmental condi-tions for tennis. Finally, these data enabled an evaluation of the current Extreme Heat Policy and the suggestion of an alternative method for assessing heat stress in tennis (the Belding and Hatch Heat Stress Index).

Hypotheses: There is expected to be a range of environmental conditions (the prescriptive zone) in which thermoregulation is successful and body core temperature is maintained relative to the workload but independent of the environmental stress.

P h D t h e s i s

Sarah MoranteMed Sci Tennis 2008:13(2):8-9

9

throughout matches by a mechanical anemometer. An additional observation, natural wet bulb temperature, was measured at 20 minute intervals for the calculation of Wet Bulb Globe Tem-perature (WBGT). Th e thermal properties of clothing were predicted for normal tennis attire. Metabolic heat production was predicted from a known regression equation developed for the association between relative workload (% VO2max) and rectal temperature. Th e regression equation determined for oxygen uptake (VO2) and heart rate in the laboratory for each subject was also used to predict metabolic heat production. Th e thermal strains measured during tennis included rectal temperature, skin temperature, sweat rate, heart rate and subjective responses. Rectal temperature and four skin temperatures (arm, chest, thigh and leg) for each player were recorded every minute throughout matches by custom-built temperature loggers. Each player’s heart rate was recorded at 15 seconds intervals throughout play using a heart rate monitor. Body water loss for sweat rate was deter-mined by weighing subjects fully clothed and equipped before play, after 30 minutes of play and at the completion of the match. Body mass changes would also include evaporative water loss from the respiratory tract and metabolic fuel used during activity. However, these changes are considered negligible and do not detract from the validity and reliability of this method of sweat loss assessment. Drink bottles were weighed at the same times to account for fl uid intake. During the change of ends after every six games, players indicated subjective responses of perceived exertion, thermal comfort, sweatiness and a rating of conditions (thermal sensation). Notational analysis was conducted through-out matches to assess activity patterns and workload.

Results: Air temperature ranged from 14.5 to 38.4°C, rela-tive humidity ranged from 21.8 to 73.7% and WBGT ranged between 13.5 and 29.2°C. Mean point duration was 5.8 ± 1.3 s and eff ective playing time (the proportion of the match spent in play) averaged 23.7 ± 5.2 %. Th is equates to a work to rest ratio of approximately 1 : 3.5. Positive associations were found for the change in rectal temperature with both point duration (P < 0.001) and eff ective playing time (P < 0.05). Heart rate was also positively correlated with point duration (P < 0.0001) and eff ective playing time (P < 0.05). Rectal temperature averaged 38.5 ± 0.4°C (62% VO2max) and mean heart rate was 136.8 ± 13.6 beats.min-1 (66 % VO2max). Both rectal temperature and heart rate were unaff ected by the two components of the current Extreme Heat Policy (air temperature and Wet Bulb Globe Temperature), even in conditions exceeding the thresholds for each index (35°C and 28°C, respectively). Skin temperature demonstrated a positive association with air temperature (P < 0.0001). Sweat rate averaged 13.32 ± 5.56 mL.kg.h-1 or 0.92 ± 0.42 L.h-1, and demonstrated positive relationships with air temperature (P < 0.0001), skin temperature (P < 0.0001) and rectal temperature (P < 0.03). Th ermal comfort declined with increasing rectal temperature (P < 0.03) and skin temperature (P < 0.0001). Both point duration (P < 0.002) and eff ective playing time (P < 0.0002) were reduced as conditions were rated increas-ingly diffi cult. Oxygen uptake (VO2) during tennis was 2.5 ± 0.5 L.min-1 when predicted from rectal temperature and 2.6 ± 0.5 L.min-1 when predicted from heart rate, which corresponds to metabolic heat production of 459.5 ± 76.3 W.m-2 and 483.9

± 95.4 W.m-2, respectively. Th e required evaporation for thermal equilibrium (Ereq) for the observations averaged 415.0 ± 104.5 W.m-2 and was associated with the observed sweat rate (P < 0.0001). However, the relationship between the predicted Ereq and the observed sweat rate was weaker than expected (R2 = 0.33). Air temperature and relative humidity were modelled to predict conditions where Ereq exceeded the maximum evapora-tive capacity of the environment (Emax), resulting in body heat storage.

Conclusions: Core body temperature remained controlled in environmental conditions at and a little beyond the two heat stress indices comprising the current Extreme Heat Policy. Th is suggests the current policy does not exceed the upper limit of the prescriptive zone and thereby endanger players. Both autonomic / physiological thermoregulation (increase in skin temperature and sweat rate) and behavioural / psychological thermoregula-tion (reduction in point duration and eff ective playing time) were involved in the control of core body temperature. Th e rational analysis of heat stress provides a more comprehensive approach to setting environmental limits. However, the prediction of ther-mal exchanges using standard equations was less accurate than expected, meaning these equations will need to be modifi ed for improved prediction in tennis.

Sarah Morante has completed a Bachelors degree and a PhD (April 4th, 2008) in the School of Exercise and Sport Science at Th e University of Sydney. She cur-rently operates a sport and fi tness consultancy company that ranges from providing lecturing services to higher education providers including Sydney University and sporting/fi tness organizations.

Abou

t the

aut

hor

10

Introduction to PRO U™

Player Orientation

These were performance based, like injuries, length of season, competition and expectations; all stressors typically seen in pro-fessional sports. The reported stressors from 1994 (e.g., media, parents and family) were no longer at the top of the list. These changes in the main stressors, combined with the impressive statistical results: 24 % increase in career longevity (significance p<0.2), decrease in burnout from a rate of 7% to less than 1% (significance p=0.01), demonstrate that the PRO U™ programs in place between 1994 and 2004 did positively impact the career longevity, health and well-being of players on the women’s tour.1 Consequently, the panel strongly recommended that these effec-tive PRO U™ programs be made available to more athletes and at a younger age. With this aim, from 2008, the Rookie Phase of PRO U™ programs will be available to players online.

Introduction to the Player OrientationThe Player Orientation helps players learn the on-site reali-ties and responsibilities of a professional Tour player. The key objectives of the Player Orientation are to optimize performance, enhance player health, and improve each player’s ability to make effective business decisions, ones that are beneficial to the individ-ual and the Tour at-large.The on-line modules are divided into three or more interactive lessons, to ensure the information is comprehensively covered in manageable doses. The on-line Player Orientation course includes audio, video, picture images and text. At the end of each lesson, players must pass an on-line quiz and evaluate the lesson content. Players must successfully complete each on-line course within 90 days of eligibility. The first modules to be launched in 2008 include:

When women tennis players graduate to this elite professional level from the ITF circuits and/or juniors competitions, they become more than mere competitors on the Sony Ericsson WTA Tour: they are a part of the Sony Ericsson WTA Tour (the Tour). In order to take charge of their careers, players are responsible to make wise and informed decisions. PRO U™ helps players gain the knowledge and skills they need to make these professional decisions. It aims to guide players to minimize the stressors associated with women’s professional tennis and to promote their safety, career longevity and performance.

Rookie Phase eligibilityPRO U™ is divided into three phases to ensure that as players’ rankings and needs increase, so does the level of training and skill-building. The Rookie Phase is the introductory phase of PRO U™ and houses the Player Orientation, the focus of this article. The Rookie Phase begins when a player eighteen (18) years of age or younger participates:

• In two (2) or more WTA Tour main draw singles events in a 52 week period, or

• In a Grand Slam singles (main draw or qualifying).

History of PRO U™PRO U™ programs came about as a result of the 1994 Age Eli-gibility Commission (now the PRO U™ Advisory Panel) report, which identified the major stressors in women’s professional tennis and made complementary recommendations. The 1994 Age Eligibility Commission report findings strongly indicated the need for developing skills and train these young athletes to succeed in the professional environment. Accordingly, the Player Orientation was expanded from a four-hour group session over-view of the Tour to the system now in place. The current model is a comprehensive, skill-development process, divided into multiple phases, each of which is based on the needs of the player and business requirements of her particular career stage. In 2004, the Sony Ericsson WTA Tour invested in a 10-Year-Review to determine the effectiveness of the PRO U™ programs, including the Age Eligibility Rule.1 This review is considered to be the most comprehensive study of age-related programs in the history of professional sports and included a literature review and an analysis of quantitative, qualitative and statistical data. The 2004 review indicated that new stressors had emerged.

PRO U™ is the Sony Ericsson WTA Tour’s umbrella institution for education. The PRO U™ staff is responsible for educating players and their sup-port teams from the onset of their professional careers and covers development in three core domains: • Human Development • Tennis Development • Business Development

S o n y E r i c s s o n W T A T o u r

Thomas Livengood, Ashley Keber and Kathy MartinMed Sci Tennis 2008;13(2):10-12

The PRO UTM program’s have had a positive effect on the health and well-being of the players

Copyright WTA Tour Inc.

11

An Intro to the Pro’s o History of the WTA, structure of the Sony Ericsson WTA

Tour, why PRO U™ exists, how the Tour and ITF/other tennis governing bodies work together, practical guidance on entry/withdrawal procedures, how the rankings work and the Age Eligibility Rule.2

Athlete Safety & Securityo Safety at home, safety during travel, safety at tournaments;

Tour initiatives to promote safety (e.g., code of conduct for player support team members, athlete assistance programs and services) and the Tour’s cumulative responsibility to promote a safe and healthy environment.

Rookie Hourso An in-depth, interactive lesson reviewing individual Tour

departments. Players learn: the purpose and role of each de-partment; critical rules specific to that department; credentials, qualifications and licensure of staff members in departments; and practical skills related to the topic in each lesson. The goal is that players will develop the relevant professional skills neces-sary to succeed in the Tour environment.

The following departments are covered in the Rookie Hours:• Sport Sciences & Medicine – players are introduced to the

training (treatment) room; the physical therapy and massage therapy personnel; how and where to access health services on- and off-site; Tour rules pertaining to health (example: Extreme Heat Condition Rule);2 biomechanical services, nutrition and hydration services; and injury prevention practices, like the annual physical. Practical skills include: blister treatment and prevention, contents of a first aid kit, and proper dynamic warm-up and recovery techniques.

• On-site Operations – players are educated about the Tour supervisors’ responsibilities, what it requires to run a successful event and consider the needs of the tournaments and players, and the enforcement of Tour rules (e.g., Patch Policy, Code of Conduct, Medical Time-Out).2 Practical skills include: the process of the draw and the daily schedule of play, and proper entry and withdrawal procedures.

• Player Relations – players are introduced to membership and benefits for members, the pension program, the importance of player meetings and the role of Player Council and the gover-nance of the Tour and player news and information. Practical activities include: attendance at a player meeting and meeting with a Player Council representative.

• Communications – players learn how the media works as a business and how media grows the sport and helps to connect players with the fans, and influences the image of individual players, tournaments and the Tour. Practical skills include: review of advice from former players, attendance at a press conference and a review of interview techniques.

• Marketing & Sponsorship – players learn about the sponsor-ship agreements of the Sony Ericsson WTA Tour, players’ roles with sponsors and the important relationship between players and the community, charities and fans. Practical activities in-clude: important advice on self-promotion and marketing, meet the sponsors and participate in sponsor activities.

• Athlete Assistance – aims to enhance players’ health, well-being and safety. Players learn about the services, resources and preventative strategies available to help manage the environ-mental and life stressors, improve overall coping skills and enhance performance. Practical activities include: an on-line tour of the Achieve Solutions website,3 the Athlete Assistance

Players learn how the media grows the sport (Copyright WTA Tour Inc)

>>

Th omas Livengood graduated with a Bachelors of Arts in Sociology and Russian Language and Literature from Kent State University. Tom joined the Sony Erics-son WTA Tour’s PRO U™ Department as Coordinator, in October 2003. Tom’s primary responsibilities as Coordinator, PRO U™ include development, tracking and maintenance of the Orientation program and monitoring the progress of players through the requirements of the Rookie Phase. His duties include working with players and their support teams (coaches, parents, agents) to help them learn about the professional tennis environment. He also assists with other Sony Erics-son WTA Tour educational initiatives such as the Coach Symposium and Junior forums.Before joining the Tour, Tom’ s past professional experiences include cross-cultural orientation and curriculum development and teaching international high school exchange students. He also lived in Russia for more than three years in the 1990’s, and is fl uent in conversational Russian.

Ashley Keber graduated with a Bachelors of Arts in English from the University of Florida, Phi Beta Kappa. She has worked with the Tour since 1997, where she has been the PRO U™ department head, overseeing such programs as the Age Eligibility Rule, Player Orientation, media training and mentor program. She has served on the Women’s Sports Foundation Career Development task force, the Athlete Development steering committee and has been a featured speaker at coaching conferences and an invitee to the annual Board meeting and symposium for National Center for Human Performance. Prior to joining the Sony Ericsson WTA Tour, Ashley was a broadcast liaison for the 1996 Atlanta Olympic Broad-casting group, networks which included Eurosport, BBC, ZDF, Australia 7 and NBC. While attending university, she was an instructor and residence counsellor for the UF-Nike Summer Tennis program.

Kathy Martin graduated from the Lincoln Institute of Health Sciences with a Bachelor in Applied Sciences (Physiotherapy) in 1984. She was awarded the Australian Physiotherapy Association Sports Physiotherapist title in 1999. She received her Bachelor Arts (1991) and Graduate Diploma in Adolescent Health & Welfare (2004) from Melbourne University. She is currently completing her Masters in Counselling at Monash University. Kathy was the Australian Olympic Team Physiotherapist in 2000, the Australian Fed Cup Team Physiotherapist from 1994 to 2000, and Sports Medicine Consultant to Tennis Australia from 1998 to 2003. Prior to working in tennis, she ran her own physiotherapy clinic and was the physiotherapist to the Australian Ballet Company and School and the Victorian College of the Arts. She joined the Sony Ericsson WTA Tour as a Primary Health Care Provider in 1991. She is currently the Director, Athlete Assistance, Sony Ericsson WTA Tour.Address for correspondence: Kathy Martin, Sony Ericsson WTA Tour, One Progress Plaza, Suite 1500, St. Petersburg, FL 33701, USA. E-mail: KMartin@wtatour.com

12

and Physically Speaking topics, and an introduction of Athlete Assistance personnel to a player’s support team.

• Tournament Operations – players are introduced to the be-hind the scenes functions of tournaments and how players and tournaments work together for maximum eff ect. Th ey learn the responsibilities of tournament staff and volunteers, the details of tournament marketing, fi nance and administration, and the importance of the tournament profi ting to help grow the sport, and player prize money. Practical activities include: a visit to the volunteer tent or ticket booth, a sponsor walk-through and a private tour of the facility.

Transition from the ITF to the Sony Ericsson WTA TourAt the junior level, the International Tennis Federation has developed the ITF Junior Tennis School with a goal to help the junior tennis community develop as humans and tennis players. Th is enterprise complements Tour initiatives and uses a blend of on-line education and on-site forums, which introduce players to topics including sport sciences, health, safety, media training and anti-doping. PRO U™ personnel participate in One Game initiatives, such as the Wimbledon Junior Forum, which is a collaborative seminar led by the ITF with the Sony Ericsson WTA Tour and the ATP. Past and present members of the PRO U™ Advisory Panel are also actively involved in the ITF Junior Tennis School.4

ConclusionTh e purpose of the Player Orientation is to educate players about their responsibilities on the Tour and gain an understanding of what it means to be a professional. Th e interactive on-line course explains and brings to life the building blocks of the business. Th e player learns that she has of a vested interest to ensure the success of each tournament and the Tour to the same extent that she is responsible for her own personal success. Th e Tour is committed to and off ers professional development programming that is dynamic, eff ective and relevant to players’ lives and careers. Th e Panel continues to meet annually to provide guid-ance on all PRO U™ programming initiatives. Th e PRO U™ team strives to create, innovate and execute the best training possible for players, so they can maximize their opportunities and fulfi l their responsibilities as role models and ambassadors of the sport.

References1. Otis CL, Crespo M, Flygare CT, Johnston PR, Keber A, Lloyd-Kulkin D, Loehr

J, Martin K, Pluim BM, Quinn A, Roetert EP, Stroia KA and Terry P. Th e Sony Ericsson WTA tour ten-year age eligibility and professional development review. Br J Sports Med 2006;40:464-8.

2. Sony Ericsson WTA Tour. 2007 Sony Ericsson WTA tour offi cial rulebook. WTA Tour Inc, 2007.

3. Value options. Achieve solutions. [homepage on the Internet]. © 1999-2007. Available from: https://www.achievesolutions.net

4. McFetridge H. Back to school. ITF World: Th e International Tennis Federation’s fl agship magazine. 2007;32:26-9.

Copyright WTA Tour Inc.

Players meet the sponsors during the Rookie Hours (Copyright WTA Tour Inc)

Tennis training: enhancing on-court

Pages: 245Price: 19.95 US$

ISBN-13: 978-0-9722759-7-2

they can better understand the technical explanations of the coaches, doctors and athletes. As I am a physical trainer for the regional tennis squad and the Dutch National Paralympic Squad preparing for the Paralympic Games in Beijing, this book is defi nitely of interest for me. Additionally, it is also useful for medical specialists, tennis coaches, athletes and parents.

Marijn ZaalPhysical trainer Royal Netherlands Lawn Tennis Association

Th is book has been written by three tennis experts who combine years of academicknowledge with real-world practical coaching to truly blend the art and scienceof tennis performance.

Dr. Mark Kovacs obtained a top 100 ITF junior ranking, won a US “gold-ball,” and competed in many international tournaments including the US and Australian Open before attending Auburn University where he was an All-American and NCAA doubles champion. He has combined researched scientifi c evidence in his coaching profession both as a high-level tennis coach as well as a strength and conditioning specialist (CSCS) training hundreds of high school, collegiate, and professional athletes. In February of 2008, Dr. Kovacs was named the Manager of United States Tennis Association Sport Science in Boca Raton, Florida.

W. Britt Chandler has a master’s degree in exercise science from Auburn Universityand played collegiate tennis. He is certifi ed as both a strength and conditioning spe-cialist (CSCS) and certifi ed personal trainer (NSCA-CPT). He also is a certifi ed tennis coach through the USPTA. He currently works as both a tennis coach and strength conditioning specialist with some of the top juniors in the country. Britt is also the editorial assistant for the Strength and Conditioning Journal and has con-tributed book chapters and presentations on tennis specifi c research and training.

Dr. T. Jeff Chandler has over 20 years experience as a tennis researcher and sportsscience consultant, advisor, and author for many tennis organizations including theUSTA, USPTA, ITF, STMS and PTR. He has over 100 scientifi c publications, book chapters, and presentations relating to tennis training and performance. He is currently Department Head of Health, Physical Education & Recreation at Jacksonville State University, Jacksonville, Alabama, and is the Editor in Chief of the Strength and Conditioning Journal published through the National Strength and Conditioning Association. Dr. Chandler is certifi ed with distinction as both a CSCS*D, and NSCA-CPT* D. He is a Fellow in the American College of Sports Medicine (FACSM) and a Fellow in the National Strength and Conditioning Association (FNSCA).

At fi rst sight “Tennis training” by Mark Kovacs, Britt Chandler and Jeff Chandler could be just one of the many books about tennis training. However, after studying it in more detail, it turns out to be a ‘must-have’ book for tennis medical and performance specialists. Tennis is an individual and a technical sport. Because of the physi-ological and technical aspects of tennis, we must train the body in many areas. A player has to develop 4 sides: the player has to specifi cally develop technical, tactical, mental and physical strengths. Within the physical training there are also many aspects that need to be developed. Th e authors have succeeded with the book “tennis train-ing” to write a manageable and synoptic book for players and coaches. Th e book focuses on physical training in the sport of tennis. In general it does not give any new information. It contains summaries of existing literature and references to known facts. However, what makes this book so good is the information about training principles, training laws, periodisation and experiences from the practices, focused on tennis. Supported by science, clearly described and fi lled with pictures the book is fi lled with tennis-specifi c exercises. “Tennis training” makes physical training in tennis easy to under-stand and to use by coaches, parents and athletes. For coaches it is a perfect reference book after their education/training to tennis coach. In practice, it is a book that can easily be used particularly because of the large number of specifi c exercises. Athletes gain in detail insight in what happens with their body during training, what exercises are really important and why physical training is such an important part of their development. Parents can also benefi t from this information. Th ey are usually further removed from the practice and this way

they can better understand the technical explanations of the coaches, doctors and athletes. As I am a physical trainer for the regional tennis squad and the Dutch National Paralympic Squad preparing for the Paralympic Games in Beijing, this book is defi nitely of interest for me. Additionally, it is also useful for medical specialists, tennis coaches, athletes and parents.

Marijn ZaalPhysical trainer Royal Netherlands Lawn Tennis Association

Th is book has been written by three tennis experts who combine years of academicknowledge with real-world practical coaching to truly blend the art and scienceof tennis performance.

Dr. Mark Kovacsand competed in many international tournaments including the US and Australian Open before attending Auburn University where he was an All-American and NCAA doubles champion. He has combined researched scientifi c evidence in his coaching profession both as a high-level tennis coach as well as a strength and conditioning specialist (CSCS) training hundreds of high school, collegiate, and professional athletes. In February of 2008, Dr. Kovacs was named the Manager of United States Tennis Association Sport Science in Boca Raton, Florida.

At fi rst sight “Tennis training” by Mark Kovacs, Britt Chandler and Jeff Chandler could be just one of the many books about tennis

Tennis Training Enhancing on-court performance

B o o k r e v i e w

Mark Kovacs, W. Britt Chandler and T. Jeff ChandlerMed Sci Tennis 2008;13(2):13

13

Abou

t the

aut

hors

Tennis training: enhancing on-court

Pages: 245Price: 19.95 US$

ISBN-13: 978-0-9722759-7-2

14

Location (decreasing order of frequency) Muscle insertion Most frequent sports activities

ischial tuberosity hamstrings gymnastics, soccer, fencing, tennis, running

anterior inferior iliac spine rectus femoris soccer, athletics, tennis

anterior superior iliac spine sartorius soccer, athletics, gymnastics

superior corner of pubic symphysis rectus abdominis soccer, fencing

iliac crest abdominal muscles soccer, gymnastics, tennis

lesser trochanter iliopsoas athletics

Table 1. Most frequent sites of avulsion fractures, their corresponding muscle insertion and the most frequent athletic activities responsible for these lesions

Acute apophysiolysis (or apophyseal avulsion fracture) usually occurs between puberty and the age of 25, and is caused by violent muscle contraction.1 Sudden pain is reported, and examination may reveal loss of function, local swelling and tenderness.1 Differ-ent sports may cause acute strain on different apophyses, causing lesions on specific locations (Table 1). The most common sites are the ischial tuberosity (most frequently seen in gymnastics), ante-rior inferior spine (common in soccer and tennis) and the anterior superior iliac spine. The iliac crest is the site most often affected in tennis, but other apophyses may be involved as well (Figure 1a.).2 Initially conventional radiography with contralateral comparison (in order to differentiate a true lesion from the unfused physis) usually suffices, showing a displaced fragment at the origin or insertion of the muscle or tendon.1,3 However, plain radiographs may be misinterpreted as negative in children, when an apophyseal avulsion fracture is not displaced or when the apophysis is not ossified. In such cases, ultrasound, CT and MRI (Figure 1b) may prove helpful.4 During healing the callus on plain radiography is excessive with hypertrophy of the surrounding cortex, which may simulate an osteosarcoma or exostosis.4 MRI initially shows haematoma and periosteal stripping, although fragments without marrow are often missed.

Sports-related muscle injuries are frequent in adults and youngsters. The presentation of muscle and tendon trauma largely depends on the patient’s age: in youngsters the skeleton is weaker than in adults, whereas their ligaments and tendons can withstand more force.1 Therefore, skeletal lesions, more specifically those of the physis, are common in children.1 The type of sports activity determines the nature of the lesion. Most commonly apophy-ses of the hip and pelvis are subject to avulsion fractures in youngsters, and in tennis the pelvis is the most likely site to be affected.2 Lesions can be either acute or chronic.

A b s t r a c t

Evert J.L. Vandervliet, Filip M. Vanhoenacker, Annemiek Snoecks, Jan L. Gielen, Pieter van Dyck, and Paul M. ParizelMed Sci Tennis 2008;13(2):14-15

Imaging of

sports-related

muscle and

tendon injuries

in children and

adolescentsFigure 1. Avulsion of the iliac crest in a 17-year-old tennis player.1a. Coronal CT at the level of the iliac crest. Note the separation of the left iliac crest from the underlying iliac bone (arrow).

1b. Axial T2-weighted MR image demonstrates the presence of a high signal intensity cleft between the avulsed apo-physis and the iliac bone (arrow). Note also high signal intensity edema within the adjacent abdominal wall muscles (asterisk).

Evert Vandervliet, MD is resident radiology at the University Hospital Antwerp, UZA and the AZ St. Maarten in Duff el-Mechelen, Belgium.

Filip Vanhoenacker, MD, PhD is radiologist at the University Hospital Antwerp, UZA and the AZ St. Maarten in Duff el-Mechelen, Belgium and guest lecturer at the University of Antwerp.

Annemiek Snoeckx, MD, is senior resident at the University Hospital Antwerp, UZA.

Jan Gielen, MD, PhD, is co-chair at the Department of Radiology and section head of Musculoskeletal Radiology, UZA and assistent professor of Radiology at the University of Antwerp.

Pieter Van Dyck, MD, is staff member Musculoskeletal Radiology, UZA.

Paul Parizel, MD, PhD, is chairman of the Department of Radiology, UZA and full professor of Radiology at the University of Antwerp.

Address for correspondence: F.M.Vanhoenacker, Dept of Radiology, University Hospital Antwerp, UZA, University of Antwerp, Wilrijkstraat 10, B-2650 Edegem, Belgium. Tel: +32 3 821 3532, Fax +32- 3 825 2026 e-mail: fi lip.vanhoenacker@telenet.be

15

References1. Rossi F, Dragoni S. Acute avulsion fractures of the pelvis in adolescent competi-

tive athletes: prevalence, location and sports distribution of 203 cases collected. Skeletal Radiol 2001;30:127-31.

2. Vanhoenacker FM, Snoeckx A, Gielen JL, Van Dyck P, Parizel PM. Imaging of muscle injuries in children and adolescents. Flemish J Sports Med Sports Sci 2005;101:39-41

3. Bencardino JT, Palmer WE. Imaging of hip disorders in athletes. Radiol Clin N Am 2002;40:267-87.

4. Boutin RD, Russell CF, Steinbach LS. Imaging of sports-related muscle injuries. Radiol Clin N Am 2002;40:333-62.

5. Vandevenne JE, Vanhoenacker F, De Beuckeleer L, De Schepper AM. Chronic avulsive injury of the hip. JBR-BTR 2000;83:31.

Subacute and chronic avulsion fractures or insertional overuse lesions typically involve the proximal attachments of the gracilis (gracilis-adductor syndrome) and adductor muscles (chronic proximal adductor insertion avulsion syndrome) or distal adduc-tor brevis muscle attachments (chronic distal adductor insertion avulsion syndrome or thigh splints).5 Radiographic fi ndings of the proximal gracilis-adductor syndrome consist of a mixture of bone rarefaction and reactive sclerosis that mimic normal variants, osteomyelitis or neoplasms (Figure 2).5 Periosteal bone apposition at the medial proximal third of the femur can be seen in thigh splints. Scintigraphy shows an elevated tracer uptake whereas MRI initially demon-strates bone marrow and soft tissue edema in all cases, and fatty replacement and sclerosis in the later stages of proximal gracilis and adductor injuries.3,5 Th us MRI may demonstrate a variable signal according to the reparative stage of the lesion (either due to edema, fatty reconversion or sclerosis).5

Musculotendinous injuries are treated conservatively, although in acute avulsion fractures surgery may be necessary if displace-ments exceed 2 cm, or when malunited or hypertrophic frag-ments cause prolonged complaints.4

Conclusions1. In the adolescent, the physis is particularly susceptible to

trauma.2. Th e nature of the sport determines the pattern of injury.

Lesions due to tennis usually involve the inferior and superior anterior iliac spine, the ischial tuberosity and the iliac crest, but other apophyses may be aff ected as well. Both the radiologist and the sports physician should be aware of these lesions.

3. During the healing phase the excessive callus formation of acute /avulsion lesions may simulate an osteosarcoma or exostosis.

4. Th e diff erential diagnosis of chronic overuse injuries in the immature skeleton includes normal variants, osteomyelitis and tumoral lesions.

Abou

t the

aut

hors

Axial CT demonstrates an irregularly delineated bony mass at the insertion of the left rectus femoris muscle at the AIIS, due to unremodelled callus for-mation. In the absence of history of previous sports trauma, this may mimic a malignant bone tumor.

Figure 2. Old apophyseal avulsion fracture at the inferior anterior iliac spine in a 15-year-old male tennis player.

16

ITF hosts successful

TST Congress

The ITF Science & Technical Department hosted

its 3rd International Congress on Tennis Science &

Technology (TST) at Whitelands College at the Uni-

versity of Roehampton in London 10-12 September

2007. Over 90 of the world’s leading tennis science

and technology researchers were present for three

days of outstanding presentation and discussion.

Tennis Science & Technology 3S. Miller and J. Capel-Davies (eds)

London: International Tennis Federation, 2007

Pages: 204Price: 60 US$

ISBN: 1-903013-34-8www.itftennis.com

C o n f e r e n c e r e p o r t

17

C o n f e r e n c e c a l e n d a r 2 0 0 8

June 2008

2nd World Congress on Sports Injury Prevention Oslo, 26-28 Junehttp://www.klokeavskade.no

July 2008

American College of Sports Medicine; International Team Physician Course Santiago, 23-25 Julyhttp://www.acsm.org

August 2008

STMS North American Regional Conference Cincinnati, Ohio, USA1-2 Augusthttp://www.stms.nl

October 2008

STMW World CongressTokyo, 2-4 Octoberhttp://www.icstms2008.jp/

British Association of Sports and Exercise Medicine Annual CongressBrighton, 8-10 Octoberhttp://www.basem.co.uk/

November 2008

International Federation of Sports Medicine; FIMS World CongressBarcalona, 18-23 Novemberhttp://www.femede.es/congressbarcelona08

Almost 50 presentations were given, the standard of which was extremely high. In addition to academics, the delegates included representatives from the equipment manufacturers, coaches, court constructors and national governing bodies. The congress was officially opened by ITF Vice President Geoff Pollard who commented that the Congress was a gathering of “the brains of tennis”, and how understanding technology was crucial to the future of the game. In addition, he contributed to four scientific papers which focused on the probability of a player winning a match based on improving their level of play at different stages of the match.

Two keynote presentations were given: the first, by Dr Stuart Miller, ITF Head of Science & Technical, and which opened the Congress, discussed the role of the Science & Technical Department in the development of rules and regulations for tennis equipment. This presentation included an overview of the projects undertaken by the ITF Technical Centre, and their contribution to the understanding and protection of the nature of tennis. The second was presented by Professor Steve Haake of Sheffield Hallam University, Great Britain, who examined the evolution of the tennis racket and its effect on serve speed.To encourage debate amongst the delegates, a discussion panel, entitled ‘Rules are made to be broken: where does tennis go from here?’, addressed current issues with respect to the Rules of Tennis. As Chairman of the ITF Rules of Tennis Committee, Geoff Pollard played a major part on the distinguished panel, and was joined by Chris Bowers( journalist and broadcaster), Steven Martens (LTA Head of Technical Support), Angie Cunning-ham (Vice-President, Player Relations, Sony Ericsson WTA Tour), and Ralph Schwenger (Head Sport AG, R&D Director

Racketsports). Among the many topics discussed during the discussion were electronic line-calling, equipment development, player physiology and coaching.

The quality of presentations was extremely high, and covered a variety of topics, including equipment technology, player develop-ment and analysis, and the environment. The second Howard Brody Award (sponsored by CISLunar Aerospace) for outstand-ing contributed paper, which was presented in person by Profes-sor Brody, went to Simon Choppin of Sheffield University, Great Britain, for a paper on the three-dimensional analysis of racket and ball during play. Professor Brody commented that the 3rd TST Congress was thought-provoking, and generated more interaction between delegates than either of the two previous events.

Over 40 delegates took the opportunity to visit the ITF Techni-cal Centre, which contains the world’s leading tennis-specific research and testing laboratory. Prior to the congress dinner being held at the All England Lawn Tennis Club, delegates also had the opportunity to tour the facility for a behind-the-scenes look at Wimbledon.The congress dinner was attended by ITF President Francesco Ricci Bitti, who stressed the importance of technology in tennis, and the responsibility of the ITF to control the nature of the game through an understanding of equipment.

Proceedings, containing all the papers presented at the Congress, are available for purchase through the ITF Store https://store.itftennis.com.

18

Preventing ankle sprains and improving balance in

tennis playersIntroduction Tennis is a popular sport, with an increasing number of active players.1-3 Although tennis is a non-contact sport, it is associated with a number of injuries.2-5 Most injuries in tennis occur in the lower extremities,4-5 consisting primarily of muscle strains and ligaments sprains in the ankle and knee,2-6 followed by the upper extremities and trunk area.5 Furthermore, tennis is a sport that requires speed, power, and functional strength movements for an extended period. There-fore, it is important to train the tennis player to maximise his performance while incorporating specific exercises to elimi-nate injury risk factors.7 More specifically, specialists propose strengthening exercise programmes to restore muscle imbalances, stretching exercise programmes to decrease muscle stiffness and balance exercise programmes to improve proprioception.8-11

The term “proprioception” was described by Sherrington,12 as the awareness of body segment positions and orientations. Recent evidence in other sports, suggests that balance exercise programmes may improve proprioception and neuromuscular control, and reduce the number of lower limb injuries.9,13-17 Proprioception is especially important for tennis players, because tennis movement characteristics are complex, the footwork is demanding and a high level of balance is required.18,19 Since bal-ance is one of the fundamental qualities that tennis players must develop20 tennis-specific balance exercises should be included in a player’s daily training routine in order to maximise performance and minimise injury risk.9,21,22 The aim of the present paper was to present a structured programme of how to incorporate specific balance exercises for tennis players to improve balance and prevent lower limb injuries.

Specific characteristics of the balance exercise programme According to the previous studies: 1. The content of the balance exercise programme should be

incorporated into tennis training drills because all the exercises are designed to be a natural part of playing movements; 15,17

2. The tennis-specific balance exercises should be done on a tennis court or in a controlled environment (e.g. gym room) and allow the joints to move in the same way as they would in normal functional tennis activities;17,23

3. The exercises may be progressed by changing from bilateral to unilateral standing in the first drill only;

4. The exercises performed on balance boards require a combina-tion of balancing skills and certain tennis skills (e.g. dribbling, ground strokes and volleys);

5. The duration of each drill should be increased progressively.

The balance exercise programmeThe combination of tennis drills and balance exercises make the training session more sport-specific and interesting. The specific

balance exercise programme includes a closed-chain lower limb position. The proposed pieces of equipment are a mini-trampo-line, balance boards with air and wooden balance boards. The use of a mini-trampoline can change the weight bearing surface from hard to soft and provide an element of instability, thus requiring more control in the weight-bearing lower extremity exercises for stability.23 With regard to the balance boards; the first is a bal-ance board, 40 cm in diameter and filled with air flat side up and down. The second board is a flat wooden disk, 51 cm in diameter, and 1 cm high with a round hardwood block (9.5 cm diameter, 3.7 cm high) in the middle of its base. The board with the hemi-spherical bottom moves in all directions. With the use of these pieces of equipment, the balance exercise programme includes four different tennis drills (Table 1).

C o a c h e s c o r n e r

Vasiliki J. Malliou, Paraskevi Malliou, Asimenia Gioftsidou, Stavros Douvis and Alexandros MavvidisMed Sci Tennis 2008;13(2):18-20

Figure 1. Player (left-handed) stands on the wooden balance board with the hemi-spherical bottom surface and tries to dribble the ball with the racket.

19

Dribbling In this drill the tennis player stands with both feet on the mini-trampoline and dribbles the ball with the tennis racket (Figure 1). Then, the player does the same drill on the balance board with air and then, on the wooden balance board. The player the repeats all these exercises with a one-legged stance.

Ground strokesIn this drill, the tennis player stands in a closed position (side-ways) with both feet on the mini-trampoline. The coach feeds the ball to the player who tries to hit a forehand drive and return

Drills preformed on: Training period Rest period between each drill

a.trampoline

b.balance board with air

c.wooden balance board

First drill: Standing while dribbling

(with the racket and tennis ball) 1st wk: 20s/drill (total 6mins) 20s (total 6mins)

Second drill: Ground strokes 2ndwk: 30s/drill (total 10mins) 15s (total 5mins)

Third drill: Ground stroke/volley 3rd and 4th wk: 40s/drill (total 12mins) 20s (total 6mins)

Fourth drill: Control and ground stroke 5th and 6th wk: 60s/drill (total 12mins) 20s (total 4mins)

(Each drill performed 2 times) 7th and 8th wk: 60s/drill (total 14mins 20s (total 4-5mins)

Table 1. Recommendations for a tennis balance exercise programme

Mins, minutes; s, seconds; wk, week

Figure 2. Player stands on balance boards with air (one foot on each board) and tries to return the ball with a forehand drive.

the ball to the coach (Figure 2). The drill is then repeated on the backhand side. As the programme progresses the player does the same drill on two balance board with air (one foot on each board) and then, on the wooden balance boards.

Ground stroke and volley In this drill the tennis player stands sideways with both feet on the mini trampoline and tries to control the ball which the coach feeds before returning it with a forehand drive. The drill is then repeated using a backhand drive to return the ball. As the programme progresses the player does the same drill on two balance boards with air (one foot on each board) and then, on the wooden balance boards. >>

Figure 3. Player (left-handed) stands on a mini trampoline and tries to hit a forehand volley.

Abou

t the

aut

hors

20

Paraskevi Malliou, Ph.D. is Associate Professor and athletic trainer at the Demo-critus University of Th race, Department of Physical Education and Sports Science in Komotini, Greece.

Vasiliki J. Malliou, Ph.D is a physical education and tennis instructor at the Nati-onal and Kapodistrian University of Athens, Department of Physical Education & Sports Science, in Athens, Greece.

Asimenia Gioftsidou, Ph.D. is a physical education teacher and athletic trainer at the Democritus University of Th race, Department of Physical Education and Sports Science, in Komotini, Greece

Stavros Douvis, Ph.D. is Associate Professor and Head of the tennis course at the University of Athens, Dept of Sports Science.

Alexandros Mavvidis, Ph.D. is Associate Professor and Head of the tennis course at the University of Th race, Dept. of Sports Science.

Address for correspondence:Vasiliki J. Malliou, Ph.D., Makrigianni 36, Ilioupolis, 16345, Athens, Greece

References1. Perkins RH, Davis D. Musculoskeletal injuries in tennis. Phys Med Rehabil Clin

N Am 2006;17(3):609-31.2. Kühne CA, Zettl RP, Nast-Kolb D. [Injuries- and frequency of complaints in com-

petitive tennis- and leisure sports]. Sportverletz Sportschaden 2004;18(2):85-9.3. Bylak J, Hutchinson MR. Common sports injuries in young tennis players.

Sports Med 1998;26(2):119-32.4. Feit EM, Berenter R. Lower extremity tennis injuries. Prevalence, etiology, and

mechanism. J Am Podiatr Med Assoc 1993;83(9):509-14.5. Pluim BM, Staal JB, Windler GE, Jayanthi N. Tennis injuries: occurrence, aetiol-

ogy, and prevention. Br J Sports Med 2006;40(5):415-23.6. Silva RT, Takahashi R, Berra B, Cohen M, Matsumoto MH. Medical assistance

at the Brazilian juniors tennis circuit--a one-year prospective study. J Sci Med Sport 2003;6(1):14-8.

7. Kovacs M. Is static stretching for tennis benefi cial? A brief review. Med Sci Tennis 2006;11(2):14-16.

8. Askling C, Karlsson J, Th orstensson A. Hamstring injury occurrence in elite soc-cer players after preseason strength training with eccentric overload. Scand J Med Sci Sports 2003;13(4):244-50.

9. Caraff a A, Cerulli G, Projetti M, Aisa G, Rizzo A. Prevention of anterior cruciate ligament injuries in soccer. A prospective controlled study of proprioceptive train-ing. Knee Surg Sports Traumatol Arthrosc 1996;4(1):19-21.

10. Fried T, Lloyd GJ. An overview of common soccer injuries. Management and prevention. Sports Med 1992;14(4):269-75.

11. Rozzi SL, Lephart SM, Sterner R, Kuligowski L. Balance training for persons with functionally unstable ankles. JOSPT 1999;29(8):478-486.

12. Sherrington GS. Th e integrative action of the nervous system: Review of the aff erent neural system of knee and its contribution to motor learning. New York, Charles Scribner’s Sons, 1906.

13. Hewett TE, Lindenfeld JV, Riccobene JV, Noyes FR. Th e eff ect of neuromus-cular training of the incidence of knee injuries in females athletes. Am J Sports Med 1999;27:699-706.

14. Hoff man M, Payne G. Th e eff ect of proprioceptive ankle disk training on healthy subjects. JOSPT 1995;21(2):90-3.

15. Wedderkopp N, Kaltoft M, Lundgaard M, Rosendahl M, Froberg K. Preven-tion of injuries in young female players in European team handball. A prospec-tive intervention study. J Med Sci Sports 1999;9:41-7.

16. Malliou P, Gioftsidou A, Pafi s G, Beneka A, Godolias G. Proprioceptive training (balance exercises) reduces lower extremity injuries in young soccer players. J Back Musculoskeletal Rehabil 2004;17:101-4.

17. Gioftsidou A, Malliou P. Preventing lower limb injuries in soccer players. Strength Cond J 2006;28:2-5.

18. Lin CH, Lien YH, Wang SF, Tsauo JY. Hip and knee proprioception in elite, amateur, and novice tennis players. Am J Phys Med Rehabil 2006;85(3):216-21.

19. Jerosch J, Th orwesten L, Teigelkotter T. Proprioception of the shoulder joint in young tennis players. Sportverletz Sportschaden 1997;11(1):1-9.

20. Elstein R, Bowden MC. Tennis kinetics. New York: Simon and Schuster; 1985.21. Bahr R, Lian O, Bahr IA. A twofold reduction in the incidence of acute ankle

sprains in volleyball after the introduction of an injury prevention program. A prospective cohort study. Scand J Med Sci Sports 1997;7(3):172-177.

22. Verhagen E, van der Beek A, Twisk J, Bouter L, Bahr R, van Mechelen W. Th e eff ect of a proprioceptive balance board training program for the prevention of ankle sprains: a prospective controlled trial. Am J Sports Med 2004;32(6):1385-93.

23. Zachazewski J, Magee D, Quillen W. Athletic injuries and rehabilitation. Phila-delphia: W.B. Saunders Company, 1996.

Summary:In conclusion, we recommend tennis coaches to include balance exercises in to their players’ daily tennis training programmes to improve proprioception and potentially reduce lower limb injuries. Th ese balance exercises should be combined with tennis drills in order to be more sport-specifi c and interesting. Th e programme is intended to enhance hand-eye coordination and subconscious reaction. Th e duration of the recommended balance exercise programme should be eight weeks with a daily training duration that increases from 6 to 14 minutes (Table 1).

University Professor Dr. Rudolf Schabus was born in Hermagor/Kärnten in1954 and studied medicine in Vienna (1973-1978). He went on to specialise in traumatology at the University Clinic for Traumatology, Vienna (1979-1985) and received certifi cation as a sports physician in 1990. He is currently the Head of the Dept. of Traumatology and Sports Injuries in the Wiener Privatklinik.

Elisabeth (Lisi) Bosina was born in Vienna in 1959 and, after qualifying as a physiotherapist, she went on to specialise in sports physiotherapy. From 1989, she worked in private practice in Vienna. Shortly after the completion of this book, in 2005, she was tragically killed in an avalanche accident.

Abou

t the

aut

hors

The Knee: Patient evaluation /

Imaging / Therapy and

Rehabilitation

This book about the knee joint is a manual for

physicians, physical therapists and patients. It is

written in a way patients can understand, but

of suffi cient medical interest to be useful to

physicians such as orthopaedic surgeons

and sports physicians. The book empha-

sizes the interaction between the physi-

cian, physical therapist and patient during the

rehabilitation process. It explains how to make

a successful return to sport and how to prevent

injuries from re-occurring.

“Th e knee” is divided into three main sections. Th e fi rst section includes general information in which the anatomy of the knee is explained and biomechanical information is provided for the diff erent knee components during movement. Th e second section of the book describes common knee injuries in detail, and explains trauma mechanism, physical examination and injury-specifi c imag-ing. It also outlines conservative treatment and operative treatment techniques. To help the reader understand the recommended con-servative treatment and specifi c rehabilitation phases, each chapter is supplied with drawings of the suggested exercises. Th e operative techniques are clarifi ed by images as well, to explain the diff erent phases of the operation. Schabus and Bosina particularly focus on the anterior cruciate ligament and gonarthrosis. Th ey also discuss other common problems such as posterior cruciate ligament lesions, meniscal lesions, cartilage damage and patellar instability. Th e third section of the book explains the various exercises, using appropriate images, for stretching and strengthening the diff er-ent muscles around the knee joint. Th ere is the added bonus of a DVD showing all the exercises in the book which is provided with each copy. In summary, this book provides an excellent overview of the anatomy, injuries and rehabilitation techniques of the knee. It would be particularly useful for patients and coaches, and health care professionals starting a career in sports medicine.

Maarten Moensports physician

B o o k r e v i e w

21

Rudolph Schabus and Elisabeth Bosina Med Sci Tennis 2008;13(2):21

The Knee: Patient evaluation /

Imaging / Therapy and

Rehabilitation

This book about the knee joint is a manual for

physicians, physical therapists and patients. It is

written in a way patients can understand, but

of suffi cient medical interest to be useful to

physicians such as orthopaedic surgeons

and sports physicians. The book empha-

sizes the interaction between the physi-

cian, physical therapist and patient during the

rehabilitation process. It explains how to make

a successful return to sport and how to prevent

Rudolph Schabus and Elisabeth Bosina Med Sci Tennis 2008;13(2):21

Das Knie Diagnostik-

Therapie- RehabilitationRudolph Schabus and Elisabeth Bosina

Vienna: Springer Verlag 2007, Pages: 164, Price: EUR 99,95ISBN: 978-3-211-29686-8

www.spinger.com

Loading and velocity generation in the high performance tennis serveTh e ‘why’Shoulder injuries rank among the most prevalent and debilitat-ing injuries sustained by professional tennis players. Th e loads endured by the tissues of the shoulder during stroke produc-tion, and more particularly the serve, are commonly implicated in shoulder joint injury.1-3 Indeed, past evidence points to these loads increasing along with serve velocity, as well as with varied segment use.4 Th e aim of this thesis was to therefore quantify how diff erent types of serves (i.e. the fl at serve and the kick serve) and how diff erent service techniques (i.e. the foot-up) aff ected shoulder joint loading among high performance able-bodied and wheelchair players. Exciting in that it represented an opportunity for three-dimensional (3D) stereophotogrammetry – the gold standard in motion analysis – to evaluate a tennis stroke, and, challenging as the shoulder represents something of a ‘Holy Grail’ in upper-limb biomechanics.

Th e ‘where’, ‘who’ and ‘how’Th e Vicon 612 (Oxford Metrics, Oxford, UK) system at the School of Sport Science, Exercise and Health was utilised to track retrorefl ective markers (UWA model) placed on twelve high performance able-bodied male tennis players and two top 30 professionally ranked male wheelchair tennis players executing serves of varying type (i.e. fl at serve and kick serve) and technique. Twelve cameras, operating at 250 Hertz, minimised the prospect of marker occlusion and optimised marker reconstruction during data collection. Upper limb kinetics were calculated through inverse dynamics, where segmental masses and moments of inertia were provided from the data of De Leva 5 and Clauser et al.6

Th e challenges along the way (establishing the methodology)In tennis, normative data describing the key mechanical char-acteristics of selected strokes is widespread, yet the number of strokes upon which these data should be based has rarely been documented.7-8 Consequently, verifi cation of the repeatability of the tennis serve, and the minimum number of executions upon which representative observations could be made, needed to be established. In some agreement with theoretical models of performance analysis,9 reliable evaluation of the serve appeared to require at least three successful service trials. Determination of appropriate methods of data treatment, including an apposite smoothing technique to best represent higher-order kinemat-ics both pre- and post-impact, saw a cubic spline interpolative procedure used.Accurate 3D representation of segments requires at least three non-collinear markers, or points. Additional markers are required to defi ne points of anatomical relevance. In the upper body, esti-mation of wrist and elbow movement is relatively simple as both joints can be represented by two degrees of freedom. However, biomechanical modelling of the shoulder is complicated by its three degrees of freedom as well as the high rotational veloci-ties and large ranges of motion that punctuate its involvement in functional tasks. Further, gimbal lock (where angles become ill-defi ned as axes coincide) is of real interpretive concern when shoulder joint motion is determined via the Euler angle fl exion-extension, abduction-adduction and internal-external rotation ZXY decomposition typically used to describe all other joint motion.10 Pilot work was thus undertaken to corroborate the ISB-recommended plane of elevation, elevation and internal-ex-ternal rotation decomposition,11 and its accompanying spherical reference system, as preferrable for computing more representa-tive shoulder joint kinematics. Also, with soft tissue artefact considered the largest source of error in 3D motion analysis, a case study was needed to compare the coupling of diff erent marker/triad positions (i.e. the technical coordinate systems) and the underlying humeral bone motion.

Th e analysesStudy 1: Similar shoulder joint kinetics developed dichotomous 3D racquet velocities in the high performance able-bodied fl at serve and kick serve. Where higher peak horizontal, vertical and absolute racquet velocities were generated during the fl at serve, higher lateral velocities characterised the kick serve. Th e compa-rable shoulder joint loading conditions nevertheless point to the repetitive, long-term performance of either serve as relevant in shoulder joint injury pathologies.

Study 2: Coordinative lower limb variation in the able-bodied serve, encapsulated by specifi c front and back lower limb joint kinematics was also shown to infl uence the development of fl at serve racquet velocity. Aided by a leg drive, high-performance players generated similar absolute pre-impact racquet velocities from both foot-up and foot-back service stances. Conversely,

P h D t h e s i s

Machar ReidMed Sci Tennis 2008;13(2):22-23

22

Loading and velocity generation in the high performance tennis serve

less dynamic engagement of their lower limbs (i.e. the ARM serve: fl at serves hit with minimal active ankle, knee and hip joint fl exion-extension) saw players unable to generate commensurate pre-impact absolute racquet velocities. Interestingly, comparable shoulder joint kinetics were inherent to the fl at serve, irrespective of the noted lower limb kinematic variation. So, with diff erential absolute racquet velocities produced via similar shoulder joint loads but divergent ‘leg drives’, other links in the ‘kinetic chain’ may be more aff ected by variable lower limb involvement.

Study 3: In contrast to able-bodied serve performance, similar peak pre-impact absolute racquet velocities were generated dur-ing the wheelchair fl at serve and kick serve. Wheelchair serve tactics still demanded the development of higher peak pre-impact horizontal and lateral racquet velocities during the fl at serve and kick serve, respectively. Shoulder joint kinetics were consistent across wheelchair serve type, but specifi c to the individual players; likely varying with their level and severity of spinal cord injury. When expressed relative to absolute racquet velocity, both the high-performance able-bodied and wheelchair players tolerated comparable pre- and post-impact shoulder joint loading profi les such that related shoulder joint injury risk appears analogous between populations.

Th e ‘where to from here’ at the University of Western Australia• Ongoing biomechanical examination to establish best marker

positions and processes of shoulder joint estimation as well as most meaningful shoulder joint representation, to further enhance the calculation and interpretation of shoulder joint motion in all overhead motions.

• Examination of shoulder mechanics (inclusive of electromyog-raphy) in the fl at, slice and kick serve performance of pre- and post-pubescent high performance male and female players.

• Derivation of ball spin rate and axis during the high perfor-mance serve of adult and junior players. Determination of the key kinematic characteristics that help produce ball rotation.

References1. Chandler TJ, Kibler WB, Stracener EC, Ziegler AK, Pace B. Shoulder strength,

power, and endurance in college tennis players. Am J Sports Med 1992;20:455-8.2. McCann PD, Bigliani LU. Shoulder pain in tennis players. Sports Med

1994;17:53-64.3. Kibler WB. Biomechanical analysis of the shoulder during tennis activities. Clin

Sports Med 1995;14:79-85.4. Elliott B, Fleisig G, Nicholls R, Escamilla R. Technique eff ects on upper limb

loading in the tennis serve. J Sci Med Sport 2003;6:76-87.5. de Leva P. Adjustments to zatsiorsky-seluyanov’s segment inertia parameters. J

Biomech 1996;29:1223-30.6. Clauser CE, McConville JT, Young JW. Weight, volume and centre of mass seg-

ments of the human body. In: AMRL Technical Report 69-10. Dayton: Wright-Patterson Air Force Base, 1969.

7. Knudson D. Intrasubject variability of upper extremity angular kinematics in the tennis forehand drive. Int J Sport Biomech 1990;6:415-21.

8. Knudson DV, Blackwell JR. Variability of impact kinematics and margin for error in the tennis forehand of advanced players. Sports Engineering 2005;8:75-80.

9. Mullineaux DR, Bartlett RM, Bennett S. Research design and statistics in biome-chanics and motor control. J Sports Sci 2001;19:739-60.

10. Grood ES, Suntay WJ. A joint coordinate system for the clinical descrip-tion of three-dimensional motions: Application to the knee. J Biomech Eng 1983;105:136-44.

11. Wu G, van der Helm FC, Veeger HE, et al. ISB recommendation on defi nitions of joint coordinate systems of various joints for the reporting of human joint motion--Part II: Shoulder, elbow, wrist and hand. J Biomech. 2005;38:981-92.

Machar is the Sport Science Manager for Tennis Australia. Previously, he worked as a Lecturer in Biomechanics at the University of Western Australia, where he continues to retain an Adjunct appointment.From 2000-2004, he was the Assistant Research Offi cer for the International Ten-nis Federation (ITF), based in Valencia, Spain. A Tennis Australia Level 3 Coach, Machar’s duties included coaching some of the world’s best juniors, conducting research on the game’s professional elite, creating and delivering the ITF Level 3 course, and co-authoring several ITF publications. During that period, Machar also fi lled the role of physical training advisor to former top 10 player, Greg Rusedski, and was contracted by the Chinese Tennis Association to work with and establish a strength and conditioning framework for the country’s female elite (Li Na and Jie Zheng). Academically, Machar has completed a B.App.Sc. (Hons) in Human Movement [RMIT], PG Dip in Elite Sport Coaching [Canberra], and in December 2006, a PhD in Biomechanics [UWA].

Address for correspondence: Mreid@tennis.com.au

Abou

t the

aut

hor

23

Introduction There is a range of published material on the use of match statis-tics/probabilities to increase serving performance. Gale1 used a simple mathematical model to determine an optimal strategy for serving in tennis. Norman2 used dynamic programming to de-termine an optimal strategy of whether to use a slow or fast serve on the first and second serve. George3 used a simple probabilistic model to determine a serving strategy in tennis and stated that the usual serving strategy may not be optimal. Professional tennis matches were used as examples to support the claim. Gillman4 developed a similar analysis to serving strategies. Hannan5 also analysed different serving strategies, with the added complexity of the opponent returning the serve in such a way that the server countered with a strong shot or was forced to hit a weak shot. Pollard6 determined a method for finding the optimal risks that should be taken by the server on the first and second serves. In the above papers the effect of the receiver’s receiving capacity on the probability that the server wins a point on the first serve and on the probability that he wins a point on the second serve, is typically handled implicitly. Nowadays, with the availability of substantial data on each player’s receiving capacity (as well as on each player’s serving capacity), it is possible to address the effect of the strength of the receiver on the server’s first and second serve probabilities explicitly rather than just implicitly. Thus, a player’s serving probabilities against one player can be different from his/her serving probabilities against another. Correspond-ingly, a player’s best serving strategy against one player can be different from the best serving strategy against another. Barnett and Clarke7 showed how to predict serving and receiving player statistics/probabilities prior to the start of a match. Their model can be used to evaluate the optimal serving strategy for a player against a particular opponent. Barnett and Pollard2 showed that players’ performances are affected by the court surface for both men and women. Thus, a player’s optimal serving strategy can vary from opponent to opponent and from surface to surface. In earlier studies, such variations were handled implicitly, and were not clearly identifiable to the reader.

Abstract

A large database of tennis statistics is used to

calculate player match statistics for each court

surface. Analysis is carried out to determine

serving strategies to increase performance. The

results of the analysis could be used by players

and coaches to possibly increase serving perfor-

mance.

O r i g i n a l r e s e a r c h

Tristan Barnett, Denny Meyer and Graham PollardMed Sci Tennis 2008;13(2):24-27

24

Applying match statistics to

increase serving

performance

As an example of a player’s optimal serving strategy varying from one opponent to another, we consider the following. Consider a typical professional man (player A) whose optimal serving strategy is typically a hard first serve and a softer second serve with spin. If this player’s opponent is equally as good at receiving a first serve as receiving a second serve, it is clear that player A may just as well serve a second serve as a first serve. On the other hand, if player A’s opponent is very much better at receiving a second serve than receiving a first serve, it may be better for player A to serve two first serves than to serve a fast first serve and a slower second serve. In this paper we see how the merits of this potential strategy of two fast serves can be assessed statistically by a player about to play a specific opponent.

This paper uses a large database as provided by KAN-soft (www.oncourt.info) to calculate player match statistics for each court surface. The methods of the analysis could be used by players and coaches to increase potential serving performance.

OnCourt database The OnCourt database provides some match statistics since the 2003 French Open. Not all the match statistics for the ATP and WTA events are given. However the number of matches and tournaments included in the database has increased in recent

25

years. The database is taken from the 6th August, 2007. The sur-faces are categorized as grass, hard, indoor hard, clay, carpet and acrylic. For simplicity hard and indoor hard are considered as one surface. It is noted that acrylic will be played at the Australian Open from 2008. At August 2007, there are no match statistics recorded by the OnCourt database for matches played on acrylic.

A program was written in SAS to calculate the average serving and receiving statistics for each player on each surface. The serving and receiving statistics averaged across all matches on each surface was also calculated. Tables 1 and 2 below give these overall averages for men and women. The results indicate that women serve a higher percentage of 1st serves in play compared to men for all four surfaces. However, the results indicate that men win a higher percentage of points on the first and second serve compared to the women for all four surfaces. Overall, the results indicate that men win a higher percentage of points on serve compared to women on all four surfaces. This agrees with the results of Barnett and Pollard.8 The difference between the percentage of wins on first serve for men and for women is 8.8%. The difference between the percentage of wins on second serve for men and women is 5.5%. As the former value is greater than the latter value, there is a suggestion or possibility that a fast first and fast second serve strategy is more likely to be a rea-sonable one in a men’s match than in a women’s match. >>

26

Serving Strategies The players’ serving and receiving statistics are defined as:

ais = percentage of first serves in play for player i on surface s, bis = percentage of points won on first serve given that first serve is in for player i on surface s, cis = percentage of points won on second serve for player i on surface s, dis = percentage of points won on return of first serve for player i on surface s, eis = percentage of points won on return of second serve for player i on surface s.

The surfaces are defined as: s=1 for grass, s=2 for carpet, s=3 for hard and s=4 for clay.

Combining player statistics is a common challenge in sport. While we would expect a good server to win a higher propor-tion of serves than average, this proportion would be reduced somewhat if his opponent is a good receiver. Using the method developed by Barnett and Clarke7 we can calculate the combined percentage a player wins on his/her first and second serve for each surface. The equations are given as follows:

fijs = bis – djs + davs (1)gijs = cis – ejs + eavs (2)

where:fijs = percentage of points won on first serve given that first serve is in when player i meets player j on surface s, gijs = percentage of points won on second serve when player i meets player j on surface s, davs represents the average percentage of points won on return of first serve on surface s,eavs represents the average percentage of points won on return of second serve on surface s.

A simple analysis can now be used to compare two serving strate-gies. The first strategy is where a player serves a fast serve on the first serve and a slow serve on the second serve. It is assumed that for the data collected, players have always used a fast first serve and a second slower serve. Even if this is not always the case, it would appear to be a reasonable assumption for the following analysis. Using this strategy, the percentage of points won on serve is given by:

ais * fijs + (1- ais) * gijs

The second strategy is where a player serves a fast serve on both the first and second serve. Using this strategy, the percentage of points won on serve is given by:

ais * fijs + (1- ais) * ais * fijs

Therefore, a player should use the second strategy if

(1-ais) * ais * fijs > (1-ais) * gijs

which simplifies to

ais * fijs > gijs

Example: Andy Roddick versus Rafael Nadal Serving and receiving statistics for Andy Roddick and Rafael Nadal are given in Table 3. Equations 1 and 2 are used to calculate fijs and gijs, where davs and eavs are obtained from Table 1. The lack of matches played on carpet by both players is noted. The results from Table 3 indicate that Roddick might be encouraged to serve fast on both the first and second serve when playing Nadal on grass. However he should use a fast first serve and slower second serve when playing Nadal on both hard court and clay. Nadal on the other hand should use a fast first serve and slower second serve when playing Roddick on grass, hard court and clay. This example illustrates the fact that it can be important for a player to identify the particular surface statistics for himself and his opponent.

The above analysis indicates that Roddick might do slightly bet-ter when playing Nadal on grass by using two first serves rather than using a first serve and a slower second serve. The effect how-ever is not statistically significant. Nevertheless, Roddick might do well to mix his first and second serve when serving a second serve to Nadal. He would appear to have little to gain or lose sta-

Statistic Grass Carpet Hard Clay

WinPercentage of 1st serves in play 61.9% 61.3% 60.0% 61.5%

Percentage of points won on first serve 74.1% 73.0% 71.0% 67.1%

Percentage of points won on second serve 51.8% 51.3% 50.9% 49.2%

Percentage of points won on serve 65.5% 64.6% 62.5% 60.2%

Percentage of points won on return on first serve 25.9% 27.0% 29.0% 32.9%

Percentage of points won on return on second serve 48.2% 48.7% 49.1% 50.8%

Percentage of points won on return of serve 34.5% 35.4% 37.5% 39.8%

Number of matches 928 304 4319 3331

Statistic Grass Carpet Hard Clay

Percentage of 1st serves in play 63.1% 63.4% 62.1% 63.4%

Percentage of points won on first serve 65.4% 63.1% 62.0% 59.6%

Percentage of points won on second serve 46.1% 46.4% 45.3% 43.6%

Percentage of points won on serve 58.1% 57.0% 55.5% 53.5%

Percentage of points won on return on first serve 34.6% 36.9% 38.0% 40.4%

Percentage of points won on return on second serve 53.9% 53.6% 54.7% 56.4%

Percentage of points won on return of serve 41.9% 43.0% 44.5% 46.5%

Number of matches 881 199 3432 2293

Table 1. Match statistics for men separated by court surface

Table 2. Match statistics for women separated by court surface

Dr. Denny Meyer is a Senior Lecturer in Statistics at the Swinburne University of Technology. She has co-authored two books and has published upward of 50 articles in refereed journals. She is an applied statistician, working in areas such as sport statistics, management, tourism, mineral processing, advertising, agriculture and social research.

Dr. Tristan Barnett is an Adjunct Research Fellow in sports statistics at Swin-burne University of Technology. He has written several published papers, given presentations at international conferences and has a PhD in tennis modelling. He has appeared on many occasions in the media including SEN sports radio and 3RRR sports segment “Run Like You Stole Something”. Tristan currently works as a gaming mathematician for Sportsbet21 Pty Ltd.

Emeritus Professor Graham Pollard is a former professor of applied statistics and pro-vice-chancellor of the University of Canberra, Australia. He is a former fi rst grade tennis player and state squash champion, has a PhD in statistics from the Australian National University, and has international research publications in tennis, squash, theoretical statistics, maths education and physics.

Address for correspondence:Dr. Tristan Barnett, Faculty of Life and Social Sciences, Swinburne University of Technology, John St, Hawthorn, VIC 3122 AustraliaWebsite: www.swin.edu.au/sportEmail: strategicgames@hotmail.com

Abou

t the

aut

hors

27

tistically by such a strategy, but he might gain a moderate amount from the ‘surprise’ factor in such a strategy. Similar analyses to test for signifi cance can be performed for the other surfaces. However, it is clear that two fi rst serves will not be such a good strategy for Roddick in the case of clay surfaces.

ConclusionsTh e results indicate that separating player match statistics into diff erent court surfaces can be useful (for some players against some other players on particular surfaces) in making decisions on serving strategies. An example where one player might benefi t by serving two fast serves has been given. Th e method of analysis could be used by any player or coach to see whether serving per-formance might be enhanced during a forthcoming match. Th us, this approach could be quite a valuable tool for some players.

Player match statistics could be used in other applications. For example, match statistics separated by court surface could be used by television broadcasters as a guide to likely match outcomes and comments on strategies.

AcknowledgementTh e authors would like to thank KAN-soft for providing the database for calculating serving and receiving statistics.

Andy Roddick Rafael Nadal

Statistic Grass Carpet Hard Clay Grass Carpet Hard Clay

ais 0.67 0.69 0.66 0.57 0.69 0.70 0.66 0.71

bis 0.82 0.78 0.82 0.73 0.76 0.63 0.75 0.72

cis 0.56 0.43 0.59 0.55 0.57 0.53 0.59 0.58

dis 0.28 0.23 0.29 0.28 0.28 0.26 0.31 0.42

eis 0.47 0.48 0.51 0.48 0.53 0.50 0.53 0.60

fijs 0.799 0.790 0.800 0.639 0.739 0.670 0.750 0.769

gijs 0.512 0.417 0.551 0.458 0.582 0.537 0.571 0.608

ais * fijs 0.535 0.545 0.528 0.364 0.510 0.469 0.495 0.546

Matches 37 3 99 17 24 4 72 72

Table 3. Serving and receiving statistics for Andy Roddick and Rafael Nadal

References1. Gale D. Optimal strategy for serving in tennis. Mathematics Magazine

1971;44:197-9.2. Norman JM. Dynamic programming in tennis-when to use a fast serve. J Oper

Res Soc 1985;36:75-7.3. George SL. Optimal strategy in tennis: a simple probabilistic model. Appl Stat

1973;22:97–104. 4. Gillman L. Missing more serves may win more points. Mathematics Magazine

1985;58(4):222-4.5. Hannan EL. An analysis of diff erent serving strategies in tennis. In: Management

Science in Sports. Ladany SP, Machol RE, Morrison DG (eds). Amsterdam: North–Holland Publishing Company, 1976:125–36.

6. Pollard GH, Pollard GN. Optimal risk taking on fi rst and second serves. In: Tennis Science & Technology 3. Miller S, Capel-Davies J (eds). London: Interna-tional Tennis Federation, 2007:273-80.

7. Barnett T, Clarke SR. Combining player statistics to predict outcomes of tennis matches. IMA J Management Math 2005;16:113-20.

8. Barnett T, Pollard G. How the tennis court surface aff ects player performance and injuries. Med Sci Tennis 2007;12(1):34-7.

Australian elite tennis

juniors’ perceptions

of the importance

of mental skills

Introduction In a recent publication, Weinberg1 suggests that the challenge for most tennis players is to identify, and adopt, key elements which facilitate playing at one’s best on a consistent basis. To this end, Weinberg2 suggests mental factors are paramount, citing: (a) Jimmy Connor’s contention that tennis is 95% mental at the professional level; and, (b) the results of a survey with coaches and players that found tennis success was considered at least 50% (and as high as 80- 90%) mental. In further survey findings, Weinberg2 reports that, although players generally attributed losses to mental factors, players devote no time, or very little time (a few minutes), preparing themselves mentally for matches.

Abstract

Elite junior tennis players’ perceptions of the

importance of mental skills were investigated in

a study commissioned by Tennis Victoria. Eight

junior boys aged 13 to 17 years and seven girls

aged 12 to16 years comprising an elite training

squad at Melbourne Park responded to a ques-

tionnaire. Reponses to ratings of the importance

of mental and physical factors, and key mental

skills for success were recorded, together with

the time devoted to mental preparation prior to

important matches and explanations for match

losses. While mental factors and skills were

strongly endorsed, no gender differences were

found in these endorsements or in the time

devoted to mental preparation. Losses in impor-

tant matches were generally attributed to mental

factors. Results were interpreted in terms of the

maturity of players and shared exposure to the

State coach’s training methods and program.

Future directions in tennis mental skills research

are highlighted.

O r i g i n a l r e s e a r c h

Janet A. Young Med Sci Tennis 2008;13(2):28-31

28

Key words: elite tennis juniors, mental skills, mental skills training

In terms of teaching mental skills to players, Gould et al.3 suggest that tennis coaches should play a key role (as a player’s access to a sport psychologist may be restricted and coaches are generally the first, and most accessible, contact point for players). According to these authors, this role for coaches is proving to be a challenging one, with many coaches lacking requisite training in, and knowl-edge of, mental skills training. As concluded by these authors, “little is known about helping coaches develop mental skills in their athletes” and more research on mental skills in tennis is war-ranted.

With few studies conducted to date to address mental skills development and training with children and young adoles-cents,4-6 the aim of this study was to examine elite tennis juniors’ perceptions of the importance of mental skills for success and, further, to examine for gender differences in these perceptions. As such, this study complements research with adult elite athletes and coaches as to their perceptions of the importance of mental skills.7-8 In these peak performance studies, a kaleidoscope of mental skills were found to be associated with success, with key skills embracing focused attention, feelings of confidence, ability to control nerves and anxiety, commitment and dedication.8

In this exploratory investigation of elite juniors’ perceptions of the importance of mental skills for success it was hypothesised that:1. Elite junior players would rate the importance of mental fac-

tors for success higher than the importance of physical factors and there would be no gender differences in these ratings;

2. Elite junior boys and girls would rate the same the importance of key mental skills for success;

3. Elite junior boys and girls would devote similar time to mental preparation prior to important matches, and, time devoted to mental preparation prior to matches would increase with a player’s age;

4. Elite junior players would attribute losses in important games to mental factors.

MethodParticipantsAn elite squad of eight boys aged 13 to 17 (mean 16.1) years and seven girls aged 12 to 16 (mean 14.8) years participated in the study. The juniors, who were the top two ranked players in their age groups in the State, trained twice weekly at Melbourne Park, Melbourne, Australia under the guidance of the State coach. The coaching program conducted by the State coach did not include any formal mental skills training sessions.

MaterialsParticipants completed a self-report instrument (questionnaire) that was developed for the purposes of this study and consisted of both quantitative (n = 7) and qualitative (n = 1) measures. The quantitative measures consisted of asking participants to rate the importance of the physical (e.g. fitness) and mental (mind, thinking) aspects of tennis for success on a 5-point Likert scale9 (anchored where 1 = not important at all to 5 = extremely im-portant). Using the same 5-point Likert scale, and adapting Wil-liams and Krane’s8 psychological profile of a sporting champion, participants were also asked to rate the importance for success of: (a) success of determination and commitment; (b) self-belief; (c)

ability to control one’s nerves and anxiety; (d) concentration; and, (e) love and interest in tennis. In addition, participants reported on how much time they devoted to mental preparation before an important match. The qualitative measure in the questionnaire consisted of asking participants to nominate reasons for their losses in important matches.

ProcedureAfter receiving informed consent from players’ parents, the inves-tigator met with participants prior to a training session at Mel-bourne Park. The investigator outlined the study’s purpose and advised participation in the study was voluntary, there was with no requirement for players to identify themselves in responding and there were no correct, or incorrect, answers. All participants completed the questionnaire within 20 to 30 minutes.

Data AnalysisTo analyse the quantitative data, a number of inferential statistics was conducted. Specifically, a series of seven Mann-Whitney U-tests were conducted to examine for differences in: (a) ratings of importance of physical and mental factors; and, (b) ratings of five key mental skills by gender. An independent t-test and a Pearson’s product moment correlation were also conducted to examine for gender differences in the amount of time devoted to mental factors prior to matches and the relationship between the amount of time devoted to mental preparation and age of participants respectively.

To analyse the qualitative data, an inductive content analysis of participants’ accounts for their losses in important games was conducted. In a popular procedure adopted by qualitative researchers,10 key words, phrases or statements (referred to as ‘raw data themes’) were identified in participants’ narratives. Raw data themes sharing explicitly similar meaning were subsequently grouped into higher order (general) dimensions. In a final pro-cedure, these general dimensions were classified as physical (e.g. physical fitness), mental (e.g. motivation) or other (e.g. weather, court conditions) factors in accord with Weinberg’s1,2 descrip-tions of these factors.

29

>>

Results Mental skills and successParticipants’ ratings of the importance of physical and mental factors for success are presented in Table 1.

DiscussionIn summary, the study found that elite junior players: 1. Considered physical and mental factors to be equally impor-

tant for success, with no gender differences in these percep-tions evident;

2. Strongly endorsed the importance of key mental skills and attributes - determination and commitment, self confidence, ability to control nerves and anxiety, concentration, love and interest in tennis – with no gender differences in these percep-tions evident;

3. Spent between 1-30 minutes mentally preparing prior to important matches, with no gender differences evident in the time devoted to mental preparation by players;

4. Nominated an array of factors (e.g. choking, attack of nerves, a lack of motivation and self confidence) to explain losses in important matches. The majority (78%) of nominated factors were mental ones, although a lack of physical skills was a shared general dimension of factors across elite junior boys and girls.

It was an aim of the study to examine for gender differences in elite juniors’ perceptions of mental skills, and it is noteworthy that no gender differences were found across a number of mea-sures. This finding suggests there may have been a comparable level of maturity shared by the elite junior boys and girls in this study. It is also possible that the finding of no gender differ-ences arises as a consequence of all players, as members of an elite training squad, sharing a common (or similar) training and coaching program conducted by the State coach.

As such, the study’s findings suggest that elite junior players possessed an acute awareness of the importance of mental skills and attributes for success. While this awareness of the impor-tance of mental factors did not differ significantly from players’ perceptions of the importance of physical factors, a set of five

30

Table 1. Mean ratings by elite juniors (by gender) of the im-portance of physical and mental factors for success in tennis on Likert scale

Factor Mean rating: Mean rating:

junior boys junior girlseach drill

Physical 4.75 4.71

Mental 4.88 4.71

Table 2. Mean ratings by elite juniors (by gender) of the impor-tance of key mental skills and attributes for success*

Mental skill Mean rating: Mean rating:

and attribute junior boy junior girl

Determination and

commitment 4.75 4.86

Self confidence 4.88 4.71

Ability to control

nerves and anxiety 4.50 4.57

Concentration 4.62 4.86

Love and interest in tennis 4.88 4.42

Table 3. General dimensions of factors cited by elite juniors (by gender) for losses in important matches

General dimension: General dimensions:

junior boys junior girls

• Loss / lack of concentration • Loss / lack of concentration

• Motivation problems • Lacked self-belief

• Inability to control nerves • Inability to control temper

• Lacked physical skills • Lacked physical skills

• Inappropriate tactics A Mann-Whitney U-test revealed no significant differences in participants’ ratings of the importance of physical and mental factors for success (Mann-Whitney U = 59.5, p>0.05).

Participants’ ratings of the importance of five mental skills and attributes for success are presented in Table 2.

The classification procedure on the nine general dimensions listed in Table 3 revealed the majority (78%) of dimensions were mental factors (with the one exception of the dimension of lacked physical skills).

* adapted from Williams and Krane8

A series of five Mann-Whitney U-tests revealed no significant differences between junior boys’ and junior girls’ ratings of the importance of each of the five skills and attributes listed in Table 2.

Mental preparation timeIn terms of time devoted to mental preparation before an important game, junior boys reported spending between 1 to 30 minutes (mean 12.5), compared with 10 to 20 minutes (mean 18.9) reported by junior girls. An independent t-test revealed no significant differences between junior boys and junior girls in terms of their mental preparation time (t (13) = -1.5, p>0.05) and a Pearson’s product moment correlation revealed no signifi-cant relationship between mental preparation time and age of player (Pearson’s product moment = -0.16, p>0.05).

Players’ attributions for lossesThe results of the content analysis of players’ explanations for losses in important matches are presented in Table 3.

key mental skills and attributes were strongly endorsed and match losses were, in the main, attributed to mental factors. Th e importance attributed to mental skills by elite junior players was further strengthened in the reporting by all players of a set period of time devoted to mentally preparing for important matches. As such, this study’s fi ndings are consistent with, and lend support to, fi ndings from studies on adult athletes and coaches’ percep-tions of the importance of mental skills7 and a mental skills profi le linked with successful performance.8

Th e implications of this study suggest it would be appropriate, and responsible, for coaches (qualifi ed/trained in sport psychol-ogy) to integrate mental skill training into elite juniors’ normal training schedules. Mental skills training need not be deferred to post-junior or open coaching programs but could be introduced at an earlier stage of development for aspiring players.1-3 Th e juniors in this study (who received no formal mental skills training in the State coaching program) clearly demonstrated an awareness of the importance of mental factors and skills and had already adopted a key guideline of such a mental skills training program in setting aside specifi c time to mentally prepare for matches.

Several factors limit the validity of this study’s fi ndings includ-ing the small sample size (albeit ‘an information rich’ group of participants11) and a restricted number of questions adopted in the questionnaire. Th is study’s fi ndings suggest much could be gained in adopting a qualitative approach in future research to further explore elite junior players’ perceptions on what it takes to be a champion and what suggestions they would off er for aspiring players to adopt to achieve excellence and enjoyment in competing.

As an exploratory investigation of elite juniors’ perception of mental skills, this study starts to address Gould et al.3 call for more knowledge about mental skills in junior tennis. If this were a tennis match, it would be appropriate for the umpire to now call the score at ‘advantage researcher’, being a time ripe for a fuller understanding of those elements underpinning success in junior tennis.

References1. Weinberg R. Sport psychology and tennis. In: Dosil J (ed). Th e sport psychologist’s

handbook. Chichester: John Wiley & Sons, 2006:285-301.2. Weinberg R. Th e mental advantage. Chicago: Leisure Press, 1988.3. Gould D, Damarjian N, Medbery R. An examination of mental skills training in

junior tennis coaches. Th e Sport Psychologist 1999;13:127-43. 4. Crespo M, Cooke K. What research tells us about junior tennis. ITF Coaching

Sport Sci Rev 1999:20:17-8.5. Vealey RS. Future directions in psychological skill training. Sport Psychol

1988;2:318-336. 6. Weiss MR. Psychological skill development in children and adolescents. Sport

Psychol 1991;5:335-54. 7. Orlick T, Partington J. Mental links to excellence. Th e Sport Psychologist

1988;1:105-30. 8. Williams JM, Krane V. Psychological characteristics of peak performance. In:

Williams JM (ed.). Applied sport psychology: Personal growth to peak perfor-mance (4th ed). Mountain View: Mayfi eld, 2001:162-178.

9. Lehman, RS. Statistics and research design in the behavioral sciences. Belmont: Wadsworth Publishing, 1991.

10. Jackson SA. Toward a conceptual understanding to the fl ow experience in elite athletes. Res Q Exerc Sport 1996;67(1):76-90.

11. Patton MQ. Qualitative evaluation methods (2nd ed.). Beverly Hills: Sage, 1990.

Dr Janet A Young, B.Com., BA (Hons), PhD, MAPS, is a lecturer in the School of Human Movement, Recreation and Performance at Victoria University and also conducts a sport psychology practice based in Melbourne, Australia. Her research interests include optimal performance and experiential states, talent development, mental toughness and retirement from sport. Dr Young has had a long involvement in tennis both at a National and Internati-onal level in roles including Head of Women’s Tennis at Tennis Australia, Tour Director for the Women’s Tennis Association, Australian Fed Cup Manager, Tournament Director of the Richard Luton Properties Canberra Women’s Classic and member of the ITF Women’s Pro Circuit Committee. As a former Australian representative, Dr Young was a member of two winning Fed Cup Teams. Tennis Australia and the International Hall of Fame recently honoured Dr Young for her contributions to Australian Tennis.

Address for correspondence: Dr Janet Young, Sport, Recreation and Fitness, School of Sport and Science, Victoria University, PO Box 14428, Melbourne Vic 8001, Australia.

Abou

t the

aut

hor

31

32

Meet the expert:

Dr. Gary Windler

Dr. Gary Windler is an orthopaedic surgeon spe-

cializing in sports medicine in Charleston, South

Carolina. Dr. Windler is a member of the ATP Medical

Services Committee, and has served as a tourna-

ment physician for ATP and WTA tournaments.

He is a team physician for professional soccer,

ice hockey, and baseball teams in Charleston as

well as Charleston Southern University.

Long Beach, California, and a second orthopaedic clinical and research fellowship at the Nuffield and John Radcliffe Hospitals in Oxford, England. Why did you do these fellowships and what did you learn from it?

I wanted to pursue a career in sports medicine. The fel-lowship in Long Beach prepared me most for developing my sports medicine practice. However, Dr. Jackson was a wonderful mentor who taught me much more than just orthopaedic sports medicine. The year I spent in

Oxford provided a tremendous cultural experience – my wife Rhicky and I lived with orthopaedic fellows and their

families from nine different countries. I gained an awareness of the similarities and differences in how medicine is practised in countries outside of the United States.

4. When did you first get involved in ‘tennis medicine’?

I attended a STMS meeting in Ponte Vedra Beach, Florida in the mid 90s. That is when I realised there were many talented people who shared an interest in tennis medicine and science.

5. You were an ATP Traveling Sports Medicine Fellow in 2000. How did that happen and what have you learned from it?

I was extremely fortunate to have been given the opportunity by Dr. David Altchek and Dr. Per Renström to step into that position. Most of the six months was spent travelling to tournaments in the U.S. and Europe as a representative of the ATP Medical Services. That experience helped me to better understand what the players go through on a physical and emotional level being on tour week in and week out for 11 months of the year. It also provided a unique insight into the challenges of providing medical care to professional tennis players on tour.

6. You have been a member of the ATP Medical Ser-vices Committee since 2000 and are currently one of the ATP Medical Directors. What is your main task?

1. What are your favourite sports and how did you become interested in tennis?

I played American football, basketball and lacrosse in high school and went on to play college lacrosse. I really didn’t play any ten-nis until college when I began playing recreationally. I’ve been hooked on it ever since. As I get older, and unfortunately a step slower, it’s still exciting to me to learn how to hit a new shot that I couldn’t hit before.

2. Why did you decide to pursue a career in orthopaedic surgery?

When we were going through our clinical rotations in medical school, I found that I related best to the orthopaedic residents. Also, since I was always involved in sports, orthopaedics seemed like a natural fit for me.

3. You did a fellowship in Knee and Sports Medicine under the direction of Dr. Douglas W. Jackson in

Med Sci Tennis 2008;13(2):32-33

33

The ATP Medical Services Committee is responsible for coordinat-ing all aspects of player medical care at ATP tournaments around the world. This can be somewhat of a daunting task. Unlike taking care of a sports “team”, the professional tennis “tour” functions more like a travelling circus. We have players from many different countries with a variety of injuries and illnesses to contend with. Fortunately, over the years, we have been able to put together a very talented group of ATP Sports Medicine Trainers and Tournament Physicians to take on the responsibility of providing medical care at these events.

7. You have done many ‘physicals’ on ATP players with Todd Ellenbecker. What is the purpose of these physicals and what have you learned from them?

Todd and I started doing musculoskeletal screenings on the players during the 2006 season. The primary aim of these screenings is to identify muscle weakness, joint and muscle inflexibilities and muscle imbalances that may contribute to an increased risk of injury. By pro-viding players with an individualised exercise programme to address any deficiencies that are found, we hope to be able to reduce the num-ber and severity of injuries and perhaps improve performance as well.

8. In which areas of tennis medicine is further research needed?

Unfortunately, injury prevention is an area that is poorly under-stood in tennis and sports medicine in general. We hope that the musculoskeletal screenings we are doing will help us develop a profile of what a healthy professional tennis player looks like. By implementing more refined screening methods, I believe that bet-ter strategies for injury prevention can become a reality.

9. Every two years, the ATP organizes a Tournament Physician Conference for all the doctors working at ATP Tournament. What are the goals of these meet-ings and are those goals accomplished?

The ATP, through its support of the Tournament Physician’s Conference, provides the opportunity for the many dedicated people involved in providing medical care at ATP and Grand Slam tournaments to come together. The goals of the conference are to discuss tournament medical issues, present some of the latest information in tennis medicine and science, and promote collegiality and a sense of team building among the ATP Tourna-ment Physicians. We have been very pleased with the feedback we have received from participants and so I think that our goals are being achieved.

10. You are currently involved in a joint project be-tween the ATP and WTA in the development of a comprehensive medical documentation system. How do you envision this new system impacting the ATP and WTA players?

This collaborative project has been in the works for a couple of years now. It has proved to be quite an undertaking. Once imple-mented, it will improve communication among the ATP Sports Medicine Therapists, WTA Primary Health Care Providers and Tournament Physicians. They will have access to a more com-plete medical record. This will help to improve the care that the players receive at tournaments around the world. In addition, the system will ultimately enhance our ability to collect and analyse meaningful injury data.

Dr Gary Windler (right) examines Max Mirnyi’s shoulder

What is the best serving

strategy?

AbstractA player can get a high percentage of fi rst serves into court by taking a low risk on fi rst service, or can get a lower percentage of fi rst serves into court (with a higher probability of winning the re-sultant point if the serve goes into court) by taking a higher risk on service. This characteristic also applies to second serves. In this paper the relationship between the risks taken (on fi rst and second serves) and the prob-ability of winning the point is considered. Using Wimbledon Championships Men’s Singles data, it is shown that the relationship between the risk taken on a serve and the probability of winning that point (if the serve goes into court), is typically not a linear one. It appears that for most players quadratic relationships are needed to model this type of data. Finally, some practical suggestions are made as to where the server might best focus his/her attention on how to increase the probability of winning a point on service.

IntroductionTh e problem outlined in this paper has been considered by sev-eral authors. Gale1 described a graphical method for identifying the best fi rst serve and the best second serve from a set of serves. Redington2 concluded that in the 1971 Wimbledon fi nal, John Newcombe would have done slightly better if he had repeated his fi rst serve instead of using a softer second serve, and that his op-timal second serve would have been somewhere between the two serves he used. George3 considered a typical player with a ‘strong’ and a ‘weak’ serve, and, under very general assumptions he identi-fi ed the circumstances in which the ‘strong followed by strong’ and the ‘weak followed by weak’ service strategies are better than the usual ‘strong-weak’ strategy. He also showed that, given his assumptions, the ‘weak-strong’ option is always suboptimal. His limited data set for men’s singles supported the common practice that the ‘strong-weak’ option is typically best, and it indicated that the ‘weak-weak’ option is worst. King and Baker4 carried out the same analysis as George for a larger data set of women’s singles. For one player in their data set, the ‘weak-weak’ strategy was preferable, whilst for another the ‘strong-strong’ strategy was best, but for the remaining ten players in the analysis it appeared that the ‘strong-weak’ strategy was best. A rather similar approach to the above ‘two-service (strong/weak) problem’ was given by Han-nan5 who also proposed a (rather impractical) game theory ap-

O r i g i n a l r e s e a r c h

Geoff PollardMed Sci Tennis 2008;13(2):34-38

34

Keywords: Query, statistics, quadratic relationship, percentage, probability

proach. More recently, McMahon and de Mestre6 addressed this ‘two-service’ problem by analyzing 414 women’s and 444 men’s grand slam matches in the year 2000. They concluded that in a surprising number of matches, one or both players would have benefited from a departure from the ‘strong-weak’ strategy. The most common beneficial change for women was to a ‘slow-slow’ strategy, and for men it was to a ‘fast-fast’ strategy (in spite of the additional double faults).

It is clear that the server in tennis is faced with challenging deci-sions. On the first serve for example the server can serve a rela-tively safe serve which has a high probability of going into court, but the receiver is quite likely to be able to receive such a serve satisfactorily. Alternatively, the server can elect to play a faster ser-vice aimed closer to the corners of the service area, with a higher probability of winning the point if the serve goes into court. However, such a serve is more likely to be a fault. There is clearly a ‘balance’ between taking too small a risk and taking too large a risk on the first service. There is also such a ‘balance’ on the sec-ond service, although the penalty for not getting the second serve into play is typically considerable (the server loses the point). Pollard and Pollard7 considered this ‘balance’ and concluded that ‘for a wide range of players, the optimal [serving] strategy is such that the first service should go into play between about 50% and about 60% of the time’, and, ‘the optimal strategy for the second serve is such that it should go into play typically between about 85-90% and 100% of the time.’ Further, they concluded that ‘a player who often gets (say) 70% of first services into play may not be serving optimally, and possibly should aim to take greater risks on the first serve. Correspondingly, a player who gets only (say) 30% of first services into play should aim to take fewer risks on the first serve. Also, a player who gets almost 100% of second serves into play may benefit from doing a few more double faults provided he/she has a sufficient increase in the probability of winning the point when the ball goes into play.’ They also studied the price paid by the server for not serving optimally.

In this paper the relationship between the risks taken (on first and second serves) and the probability of winning the point is considered. Linear and quadratic relationships are considered, and it appears that for the typical male professional player a quadratic relationship is necessary to model this situation. Finally in this paper, some practical suggestions are made as to where the server might best focus his/her attention on how to increase the probability of winning a point on service.

MethodsPollard and Pollard7 assumed that the probability of a service going into the service court, P(i), decreased as the server took greater risk with his/her service. They denoted the risk by x on a scale from 0 to 10, and P(i/x) was assumed to equal 1-0.1x. Thus, x=1 was used to represent the situation in which the server has a probability of 0.9 of putting serves into play, x=2 was used to represent the situation in which the server has a probability of 0.8 of putting services into play,….They noted that when the server takes maximum risk (x=10), he/she typically serves a very fast service aimed at the corner of the service court, and it has very little (assumed zero) chance of going into the service court. Also, when the server takes minimal risk (x=0), they noted that

he/she serves a very ‘safe’ and slowish service often with spin and not directed to a corner of the service court, and it has a very high (assumed 1) probability of going into the service court.They assumed that the probability the server wins the point given the service goes into the service court, increases as the level of risk, x, increases, and that this relationship was linear, and given by

€

P(w /i and x) = a + bx where a + bx was assumed to take values between 0 and 1 (for the relevant values of x), a > 0 and b > 0.Firstly analyzing the second service, they noted that the prob-ability the server wins the point given a second serve with risk x2 was used, is given by

€

P2(x2) = (1− 0.1x2)(a + bx2) and that the associated optimal value of x2, x2*, is given by

€

x2* =5 − 0.5r if r ≤100 if r ≥10

where r =a/b. The probability that the server wins the point given a first service with risk x1 is used and a second service with risk x2 is used (if required), is given by

€

P1(x1,x2) = (1− 0.1x1)(a + bx1) + (0.1x1)(1− 0.1x2)(a + bx2) and the associated optimal value of x1, x1*, is given by

€

x1* =6.25 − 0.25r + 0.0125r 2 if r ≤105 if r ≥10

For example, for a player who wins about 50% of points when x = 0 and the service goes into play, and about 80% of points when x = 6 and the service goes into play, a = 0.5 and b = 0.05.Thus, given a straight line relationship between the risk and the probability of winning the point if the serve goes in, the optimal risk on the first serve is 5 when r is greater or equal to 10 and is slightly greater than 5 when r is less than 10. Thus, the optimal risk on first service can never be less than 5 when the above relationship is linear. The optimal risk on first service can however be less than 5 when the above relationship is quadratic rather than linear.The average risk taken by the players in the Wimbledon Men’s Singles Championships 1992-1995 on first service was 4.06.8 Thus, it would appear that for many men or even for most men the optimal risk on first service is less than 5, and a quadratic relationship can be used to model this situation.

Using the quadratic relationship a+bx+cx2 (rather than the lin-ear one above) for P(w/i and x), it can be shown that the optimal value of x for the second serve is given by

€

x2* = (c − 0.1b+ c 2 + 0.1bc+ 0.01(b2 − 3ac) ) /0.3c

if this expression is positive, and zero otherwise. The associated value of P2(x2*) is given by

€

P2 * (x2*) = (1− 0.1x2*)(a + bx2 *+cx2 *2)

and the optimal value for the first service is given by

€

x1* = (c − 0.1b+ c 2 + 0.1bc+ 0.01(b2 − 3ac + 3cP2 * (x2*)

if this expression is positive, and zero otherwise.The probability, P, that the server wins a point is given by

€

P = P1iP (w1 /i) + (1− P1i )P2iP (w2 /i)

35

>>

/0.3c

36

where P1i is the probability that the first service is not a fault (i.e. is ‘in court’), P(w1/i) is the probability that the server wins the point given the first serve is in court, P2i is the probability that the second service is not a fault, and P(w2/i) is the prob-

ability that the server wins the point given the second service is not a fault. For the data on the 1992-1995 Wimbledon singles in the paper by Magnus and Klaassen,8 these probabilities have estimates of 0.594, 0.733, 0.864 and 0.594 respectively for men, and 0.608, 0.622, 0.860 and 0.541 respectively for women. For these men’s singles statistics the estimated probability of winning the point on the first serve is 0.733 when the estimated risk taken is 10*(1-0.594) = 4.06, and the estimated probability of winning the point on the second serve is 0.594 when the estimated risk taken is 10*(1-0.864) = 1.36. The overall probability of winning a point is 0.644. Norton and Clarke9 added service data from men’s and women’s singles at Wimbledon 2001, the French Open 2001, the Australian Open 2000-2002 plus doubles data from Australian Open 2001 to the 1992-1995 Wimbledon data uti-lized here. They noted the ‘expected’ slight differences in service statistics between the three tournaments (surfaces).

We consider now an ‘average’ professional male tennis player with the above average statistical characteristics. Further, we assume that these five statistics (0.594, 0.733, 0.864, 0.594 and 0.644) are not far from their ‘optimal’ values for this ‘average’ player. This would appear to be a reasonable assumption as it seems unlikely that, for such an ‘average’ professional player, any one of the statistics is a long way from optimal for him. The fact that the risk taken on first service is substantially less than 5 indicates that the above linear model is inappropriate, and that a quadratic one could be appropriate. Thus, fitting the above quadratic model, the estimates of a, b and c for professional male players are (to 3 significant figures) 0.491, 0.0837 and -0.00591 respectively. This fitted quadratic relationship is shown in figure 1. For professional female players, the corresponding estimates for a, b and c are (to 3 significant figures) 0.479, 0.0487 and -0.00310 respectively. In the remainder of this paper, for simplicity, the discussion is presented in terms of the data for male professional players. However, all of that discussion is directly relevant to female professional players as well.

37

It can be concluded that, for a player with the above ‘average’ statistical characteristics, it is not possible to use a straight line to explain the relationship between the risk taken on serve and the probability of winning the point if the serve goes in. A quadratic expression, however, has been used above successfully. This conclusion is not to say that a (possibly small) percentage of players does in fact have a linear relationship rather than a quadratic one. Each player could experiment with his serve with the view to identifying the nature (linear or quadratic) of their own particular risk/winning relationship. Given the quality and sample size of the above Wimbledon data however, it would seem reasonable to believe that the relationship is a quadratic one for the majority of players.

As can be seen from the previous equation, there are four options for doing this. Increase P1i, P(w1/i), P2i and/or P(w2/i). One or two of these options may be preferable to the others. To look at this, we consider the ‘average’ professional considered above. We consider firstly, and simply as an example, the above ‘average’ player improving ( just) his second serve by increasing P2i from 0.864 to (say) 1.0, whilst leaving the other three probability val-ues unchanged. If this player can increase P2i from 0.864 to 1.0, whilst leaving the other three probabilities unchanged, his overall probability of winning the point increases from 0.644 to 0.677. The curve C2 in figure 2 is a curve with various (P2i, P(w2/i)) values for the second serve such that the player’s overall probabil-ity of winning the point is always 0.677, whilst leaving P1i and P(w1/i) unchanged at 0.594 and 0.733 respectively. For compara-tive purposes, the curve C1 in figure 2 is the curve of various (P2i, P(w2/i)) values such that the player’s overall probability of winning the point remains constant at the original 0.644, whilst leaving P1i and P(w1/i) unchanged at 0.594 and 0.733 respectively.

We secondly consider increasing P1i whilst leaving the other probabilities P(w1/i), P2i and P(w2/i) unchanged at 0.733, 0.864 and 0.594, so that the overall probability of winning the point increases from 0.644 to the above value of 0.677. This value of P1i is 0.743, a considerable increase from 0.594. The curve

C4 in figure 2 is the curve of (P1i, P(w1/i)) values such that the player’s overall probability of winning the point is 0.677, whilst leaving P2i and P(w2/i) unchanged at 0.864 and 0.594 respec-tively. Also, for comparative purposes, the curve C3 is the curve of (P1i, P(w1/i)) values such that the player’s overall probability of winning the point remains at the original 0.644, whilst leav-ing P2i and P(w2/i) unchanged at 0.864 and 0.594 respectively. Thus, it can be seen that the above player can lift his probability of winning a point from 0.644 to 0.677 by lifting P1i by 0.149 from 0.594 to 0.743, or by lifting P2i by 0.136 from 0.864 to 1.0, or by lifting P(w2/i) by 0.094 from 0.594 to 0.688, or by lifting P(w1/i) by 0.055 from 0.733 to 0.788. Thus, the above player with ‘average’ characteristics gets the greatest return by increas-ing P(w1/i) by (say) one percentage point, then the next biggest return by increasing P(w2/i) by (say) one percentage point, then the next biggest by increasing P2i by (say) one percentage point, and finally the smallest by increasing P1i by (say) one percent-age point. Of course, it may be more difficult to increase P(w1/i)by one percentage point than to increase (say) P1i by the same amount, but it can still be useful to know the relative sizes of the various benefits achieved by such improvements in play. Thus, for the above player, increasing P(w1/i) by one percentage point has a benefit approximately 2.7 times greater than the benefit obtained by increasing P1i by the same amount ( note 0.149/0.0.055 = 2.7 approximately). Also, if the above player increased P(w1/i) by one percentage point and decreased P1i by one percentage point, his overall increase in the probability of winning the point would be about 1.65 ( a little less than 1.7 due to a negative interaction be-tween the two actions) times the increase he would have achieved by increasing just P1i by one percentage point. (Note that these factors of 2.7 and 1.65, and the general nature of the conclusion here, are not sensitive to the assumption that this player is an ‘av-erage’ player rather than any player at all.) In practice this ‘average’ player would probably try to increase more than just one of these probabilities at a time, and in doing so try to move from a curve such as C1 to one such as C2 for the second serve, and/or from one such as C3 to one such as C4 for the first serve. The graphs in Figure 2 indicate that, for the ‘average’ professional player, there >>

Geoff Pollard is the President of Tennis Australia, Vice President of the ITF and Chairman of the Technical Commission and Rules of Tennis Committee of the ITF. Prior to being elected President of Tennis Australia in 1989, he was Senior Lecturer in Statistics, Demography and Actuarial Studies at Macquarie University, Sydney. He is now undertaking a PhD at Swinburne University of Technology, Melbourne.

Address for correspondence: Geoff Pollard, Swinburne University of Technology, School of Life and Social Sciences, Melbourne, Australia

Abou

t the

aut

hor

38

References1. Gale D. Optimal strategy for serving in tennis. Mathematics Magazine

1971;44(4):197-199.2. Redington F. Usurpers. J the Institute of Actuaries Students Society

1972;20:353-4.3. George SL. Optimal strategy in tennis: a simple probabilistic model. Applied

Statistics 1973;22:97-104.4. King HA, Baker J. Statistical analysis of service and match-play strategies in ten-

nis. Can J Appl Sports Sci 1979;4(4):298-301.5. Hannan E L. An analysis of diff erent serving strategies in tennis. In: Management

Science in Sports. Ladany SP, Machol RE, Morrison DG. Amsterdam: North-Holland Publishing Company, 1976:125-136.

6. McMahon G, de Mestre N. Tennis serving strategies. In: Proceedings of the Sixth Australian Conference on Mathematics and Computers in Sport. Cohen G, Langry T (eds). University of Technology, Sydney, 2002:177-81.

7. Pollard G, Pollard G. Optimal risk taking on fi rst and second serves. Tennis science & technology 3. S Miller, J. Capel-Davies (eds). International Tennis Federation, London, 2007:273-80.

8. Magnus JR, Klaassen FJGM. On the advantage of serving fi rst in a tennis set: four years at Wimbledon. Th e Statistician 1999;48(2):247-256.

9. Norton P, Clarke SR. Serving up some grand slam tennis statistics. In: Proceed-ings of the Sixth Australian Conference on Mathematics and Computers in Sport. Cohen G, Langtry T, (eds). University of Technology, Sydney, 2002:202-9.

would appear to be greater scope for increasing the probability of winning a point by focusing (initially at least) on improving the fi rst serve outcome (i.e. P(w1/i), and possibly P1i simultaneously) rather than on improving the second serve outcome. One aspect of there being greater scope on the fi rst serve is that there is a greater (probability serve goes in) range for possible improve-ments in the fi rst serve than there is for improvements in the second serve. Another aspect (as noted above) is that there is a greater overall return on the fi rst serve (the curves C3 and C4 are closer together than are the curves C1 and C2 in fi gure 2).

DiscussionIt would appear that for many or most professional men tennis players the relationship between the probability of winning the point and the risk taken on the serve is a quadratic one, and that it is best to serve more than 50% of fi rst serves into court. For some players the relationship might be linear in the range (say) x = 3.5 to x = 5.5, in which case it can be optimal to serve only about 50% of serves into play. Th us, a player should acquire at least an approximate understanding of his/her own P(i/x) and P(w/i and x) relationships, particularly in the domain of x near 4 and 5 for the fi rst service, and correspondingly in the domain of x near 0 and 1 for the second service. Th is might be achievable over time by keeping some match statistics (even some match experimentation), as well as doing some service experiments on a practice court (possibly against an opponent).For a player with an underlying quadratic relationship, it can be seen that the slope of this quadratic relationship near x = 5 is important/critical for the fi rst serve, and the slope near x = 0 and x = 1 is important/critical for the second serve. As this slope near x = 5 decreases, x1* decreases, implying that the server should aim to get nearer 60% or even a higher percentage of fi rst serves into play. Correspondingly, as the slope near x = 0.5 increases, it can be optimal to serve a higher percentage of double faults.

ConclusionsData from the Wimbledon Men’s singles 1992-1995 Champion-ships indicates that for many men the relationship between the probability of winning the point (if the serve goes in) and the risk taken on that serve is a quadratic one rather than a linear one. Th is is important as it indicates that for such players it is typically optimal to serve greater than 50% of fi rst serves into play, and to serve a reasonably strong second serve even if it results in (say) 0-15% double faults. Th is is not to say that the relationship is not linear for some men, and if the relationship is linear for a player, it is optimal for that player to serve only 50% or even slightly less a percentage of fi rst services into play.In order to serve (close to) optimally it is useful for a player to know (at least approximately) the shape of the above relationship for his/her own services. Th rough experimentation and data col-lection this should be possible for a player.In order to improve the probability of winning a point on service, it would appear that the server might focus fi rstly on improving his/her fi rst serve outcome rather than his/her second serve outcome. In particular, he/she might focus attention on increasing the prob-ability of winning the point when the fi rst serve goes in, rather than on increasing the probability of the fi rst serve going in.

Acknowledgement Th e author would like to thank Graham Pollard for early discussions on this work, and for comments on an early draft of this paper.

Th e DVD’s sell for $ 23.95 CAD each 4 DVD set (includes Core Stability 1, 2, 3 and the Agility DVD) for $ 80.00 CAD. Information and order forms on this Fit to Play & Perform™ DVD series can be found at www.citysportsphysio.com or www.mapp-coaching.com or by contacting e-mail carl@citysportsphysio.com

Carl Petersen is a Partner and Director of High Performance Training at City Sports & Physiotherapy Clinic’s in Vancouver. He works with athletes ranging from club level to those on the WTA / ATP tennis and World Cup ski tour. He travelled fulltime with the Canadian Alpine Ski Team for 15 years. His physiothe-rapy and fi tness coaching roles have given him the opportunity to work with, coach and design training programs for Olympic Gold, World Championship Gold and World Cup medallists. Petersen has worked and lectured to physicians, therapists and coaches on 5 continents most recently in Australia, England, Ireland, Paraguay, Argentina, Turkey, Switzerland and the USA. He has published over 250 articles in a variety of publications for both the Scientifi c and lay community which have been translated into 6 languages. He has also written or co-authored 3 books including Fit to Play Tennis-High Performance Training Tips and Fit to Ski. Info at wwww.citysportsphysio.com

Nina Nittinger is the founder and manager of MAPP-Coaching. Nina is a former professional tennis player who spent over six years full time on the tour. She is a certifi ed tennis and fi tness coach of the German and Swiss Tennis Federation and she is also a mental trainer in sport psychology for professional athletes. After fi nishing her Masters in sports management she has published numerous articles and co-authored 3 books about fi tness and mental training in tennis which have received wide acclaim in the International tennis and ski community. She coaches tennis full time in Davos, Switzerland. Info at www.mapp-coaching.com

Core Stability Training on DVD

Core stability is increasing in popularity as a conditioning tool for athletes. Th e relevance of trunk muscles for optimal performance in tennis has been well established. Dr. Ben Kibler (Past-President of the STMS) has stated that “core stability is the ability to control the position and motion of the trunk over the pelvis and leg to allow optimum production, transfer and control of force and motion to the terminal limbs in integrated kinetic chain activities.”Carl Petersen and Nina Nittinger have launched a series of Fit to Play™ & Perform DVDs which demonstrates innovative and practi-cal exercises for core stability training. Th e fi rst DVD Core Stability 1 focuses on “Basework & bridging” providing versatile exercises to enhance training of the core in three dimensions (3D) and multiple planes of movement. It delivers a va-riety of exercises in lying, supine, prone, quadruped and seated bridge positions. Th e authors show expert utilisation of balance equipment, elastic resistance and ´physio-balls´.Th e second DVD Core Stability 2, “Lower core & leg training”, shows how to improve 3D core stability by connecting the lower core and legs with functional exercises that work the muscle slings in closed and partially closed kinetic chain movements. Th e extended hip position for squatting as well as optimal recruitment, balance, timing and deceleration control are also emphasized.Th e third DVD Core Stability 3 , “Upper core & arm training”, is of particular importance for tennis players given the high demands that their strokes place on the dominant upper limb. Th e authors present multiple exercises for scapular stabilisation, and deceleration of pos-terior shoulder muscles using practical and portable equipment.

All the DVDs have an introductory “warm-up” and fi nish with a “cool-down” section. Th ey also include information that the authors have edited from a video on “Agility, balance and coordination drills”. In my opinion these DVDs are of great value to doctors, therapists and coaches in their eff orts to optimise athletic function and reduce injury in tennis players. I would like to congratulate Carl and Nina for their original and practical contribution to Tennis Science!

Javier Maquirriain, MD, PhD

Core stability is increasing in popularity as a conditioning tool for athletes. Th e relevance of trunk muscles for optimal performance

Th e DVD’s sell for $ 23.95 CAD each Core stability is increasing in popularity as a conditioning tool for Core stability is increasing in popularity as a conditioning tool for Th e DVD’s sell for $ 23.95 CAD each 4 DVD set (includes Core Stability 1, 2, 3 and the Agility DVD) Th e DVD’s sell for $ 23.95 CAD each

D V D r e v i e w

Carl Petersen and Nina NittingerMed Sci Tennis 2008;13(2):39

39

Abou

t the

aut

hors

10th STMS World CongressOctober 2 – 4, 2008 Tokyo, Japan

Welcome to Japan!On the occasion of Japan being host to the 10th World Congress of the Society for Tennis Medicine and Science and on behalf of the Japan Tennis Association, I would like to extend a sincere welcome to everyone. Tennis is one of the most popular sports in Japan. Even the Emperor and Empress have enjoyed playing tennis since the days of their youth. Tennis in Japan has a long history, and already over 100 years have passed since Japan started participating in international tournaments, attaining many achievements during this time. Recently, though, it seems Japan has been left behind by Europe, the US, and other countries. The Japan Tennis As-sociation is doing all it can to improve our players, and I think everyone is well aware of the great efforts that our young players have made at international tournaments since the start of the New Year. Moreover, the Japanese National Training Center was completed this January. Now I think we will have further oppor-tunities to strengthen our players and popularize tennis. In improving players and preventing injuries, medical and scientific support is crucial. So this is an opportune time for the 10th World Congress of the Society for Tennis Medicine and Science to be held in Tokyo. The Japan Tennis Association offers its warmest appreciation for those participating in this congress, which is being held in Asia for the first time. Autumn in Japan is a truly beautiful and breathtaking season. I hope that along with the meetings and the AIG Japan Open, you will have a chance to experience some of the beauty of Japan and the depth of its traditional culture.

I look forward to your participation.

Masaaki Morita, President, Japan Tennis Association

The Organizing Committee for the 10th World Congress of STMS Congress Organizer: Moroe BeppuVice Congress Organizer: Kaoru Umebayashi, Yoshihiro MurakiSecretary-General: Takayuki Sukegawa, Shoji IshiiTreasurer: Shigemichi Kyuno

Deadline for abstract submission June 30, 2008Abstract notification information July 31, 2008Deadline for hotel accommodation August 31, 2008Deadline for early registration August 31, 2008

Organizing committee

Key information

Scientific program

Social program

Hotel Accommodations

Friday, October 3Morning Instructional lecture Symposium: injuries of the wrist Symposium: Injuries of the elbow Workshop: ultrasonography of the elbow Workshop: ultrasonography of the shoulder

Tennis playing, followed by welcome reception Date: 6.00-8.00 pm, Thursday October 2Venue: Takanawa tennis centerPrice: included in registration fee

Gala dinnerDate: Friday evening, October 3Venue: Sheraton Miyako Hotel TokyoPrice: 10.000 Yen/12.000 Yen* Gala dinner is limited to 100 persons by order of application

AIG Japan Open TennisDate: Saturday afternoon, October 4Venu: Ariake ColosseumPrice: included in registration fee* Tickets are limited to 100 persons

ChairMoroe BEPPU, MDCongress OrganizerChairman & ProfessorDepartment of Orthopedic SurgerySt. Marianna University School of MedicineKawasaki, Japan

Congress Secretariat c/o His Brains, Inc., 1013 Otokikiyama, Tempaku-ku, Nagoya 468-0063, JAPANTel: +81-52-836-3511 Fax: +81-52-836-3510 E-mail:office@icstms2008.jp

JTB Global Marketing and Travel Inc. ( JTB GMT) has reserved rooms at the following hotels for Congress participants at special discount rates. Those persons who wish to apply for hotel res-ervation are requested to complete the application form no later than September 5th, 2008 by Online. Hotel assignment will be made on a first-come, first-served basis.

Sheraton Miyako Hotel Tokyo – Adjacent to the venueGrand Prince Hotel Takawana – 10 min by taxiHotel Princess Garden - 5 min. by free shuttle bus from Meguro Station

C o n f e r e n c e a n n o u n c e m e n t

Afternoon Symposium: injury prevention Symposium: injuries of the shoulder Symposium: medical care Symposium: strengthening and conditioning for tennis Symposium: wheelchair tennis Debate

Saturday, October 4Morning Instructional lecture Symposium: injuries of the knee Symposium: Injuries of the foot and ankle Workshop: arthroscopy of the elbow Workshop: arthroscopy of the shoulder Debate

40