BIOMECHANICAL ANALYSIS OF FOOTBALL PLAY.

MUNESH KUMARMPT sports medicineDirector and HOD

EON SPORT PHYSICAL THERAPY EON HEALTH CARE

NEW DELHI

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INTRODUCTION

Soccer (or football in Europe) is the most popular sport in the world, at both grass roots and international level.

It is a sport requiring high-intensity, intermittent, noncontiguous exercise that includes many sprints of different durations, rapid acceleration, jumping, agility, and so on.8

Due to the very physical, fast paced and semi-contact nature of the sport, injuries are at regular occurrence.

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Introduction cont..

This presentation considers the biomechanical factors that are relevant to success in the game of soccer.

Two broad areas are covered: (1) the technical performance of soccer

skills; (2) the causative mechanisms of specific

soccer injuries.

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The technical performance of soccer skills

Kicking Heading throwing-in passing and trapping the ball, tackling the ball falling behavior, jumping, running and

sprinting starting, stopping and changing direction

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KICKING 1-11

Kicking is a series of rotational movements. The Aim of the player is to produce the higher

angular velocity to the foot through the kinematic chain of body segments in order to exert enough force for the ball to move.

The direction of the ball is determined by the position of the planted foot and the hip position at impact.

The length of time of the kick depends on the approach distance.

The intensity of the kick is determined by the desired distance and speed.

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Athletic Application of Kicking The standing “place-kick” can

be applied to soccer and point scoring in both rugby and football.

This kick action can be broken down into 6 stages:

- the approach - plant-foot forces - swing-limb loading - hip flexion and knee

extension - foot contact - follow-through

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Kicking Application cont.

The Approach: Angle to which the ball is about to be hit by

the player A 45-degree angle produces the greatest

peak ball velocity. Based on the approach the type of kicking is

decide. The straight kick The sweep kick In step kick Side step kick

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Kicking Application cont.

Plant-foot Forces: The ground reaction force on the plant

foot directly affects the ball speed. There is also a direct relationship between

the direction of the plant foot and the direction the ball travels. The most accurate direction of the ball can be accomplished when the foot plant position is perpendicular to a line through the center of the ball.

The optimal anterior-posterior (A-P) position of the plant foot is adjacent to the ball. This A-P position determines the flight path of the kicked ball.

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Kicking Application cont.

Swing-limb loading:

Prepares for the descending motion towards the ball.

opposite arm is raised to counter balance the rotating body.

Both arms help keep the center of gravity over the support foot and increases the moment of inertia of the trunk.

The kicking hip is extended and the knee is flexed to store elastic energy and allow a greater transfer of force to the ball.

At the end of this phase there is maximal eccentric activity in the knee extensors.

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Kicking Application cont.

Hip flexion and knee extension: In this phase the thigh is swung

forward and downward with a forward rotation of the lower leg.

The leg then begins to accelerate due to the combined effect of the transfer of momentum and release of stored elastic energy in the knee extensors.

The knee extensors then powerfully contract to swing the leg and foot towards the ball. After the kicking leg makes contact with the ball the knee is extended and the foot is plantarflexed.

this time the hamstrings are maximally active to slow the leg’s eccentric movement.

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Kicking Application cont.

Foot contact with the ball: When the foot makes contact with the

ball 15 % of the kinetic energy of the swinging limb is transferred to the ball and the rest of the energy is used by the eccentric activity of the hamstring muscle group to slow the limb down.

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Kicking Application cont.

Follow –Through: This serves to keep the

foot in contact with the ball to maximize the transfer of momentum and therefore increase speed.

This also serves to guard against injury by gradually dissipating the kinetic and elastic forces.

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Straight Kick

Approaching the ball straight on

Mostly a flexion/extension action

Minimal abduction/adduction

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Sweep Kick

Approaching the ball at an angle

Substantial abduction/adduction components

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Axis of Rotation of the HipSaggital, Frontal and Horizontal Plane

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Axis of Rotation of the Knee

Horizontal Plane

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Axis of Rotation of the AnkleESPT India

Major Muscles Contractors

Adductor Magnus

• Pelvic on femoral adduction

• Support body weight

Pectineus, Adductor Breves & Longus

• Femoral on pelvic adduction torque

• Accelerate the ball

•Hamstrings & Quadriceps

• Flexion &Extension

• Creates force

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Muscle Action during kicking preparation (right-footed kick)

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Muscle action during approach & kicking (right-footed kick)

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Muscle action during follow-through (right-footed kick)

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Torques and Center of Mass Torque: exerted by the muscles

to rotate the lower leg around the knee joint in order to move the lower leg in position to kick the ball

Torque due to gravity: knowing the line of action of the weight (perpendicular distance to the line of action of the weight of the leg)

Note: When you try to kick the ball, kick it at the center of mass- force from the foot should hit it in the center of mass to achieve total translational energy so the ball can reach farther, yet if not achieved it will be more stable

Figure 8. Torque of hip, knee and ankle in a maximal instep kick (Luhtanen 1988)

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The Role of the Arms The role of the arms in kicking is

primarily to maintain the balance of the body.

The arms are usually extended out to the sides of the body during the forward motion of the kicking leg, to help to keep the center of gravity over the support foot, and to increase the moment of inertia of the trunk and increase resistance to rotation around the spine, or the long axis of the body.

As the kicking foot contacts the ball, the opposite arm moves forward and upward across the body to help keep the trunk down and the body in balance.

http://students.umf.maine.edu/~pullenam/soccer.jpg

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Heading 12

Biomechanical analysis of heading techniques provide valuable insight into the causes and factors contributing to head loading.

It form the basis for preventive measures for reducing head loading and the related potential for injury.

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Heading methods

three phases in heading include: pre-impact, ball contact, and follow through

These can be executed during different approaches, the commonest being standing, running, and jumping.

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Pre-impact The pre-impact phase allows

the player to prepare to forcefully impact and direct the ball at the target intended

The phase has following component – feet placed in a split stance – knees bent – torso extended rearwards about

the hips – shoulders squared – eyes fixed on the ball

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Ball contact

Ball contact with the forehead is recommended, not with the top of the head.

This phase has following component torso flexed forwards to meet

the ball head and shoulders move in

unison with the torso head contacts ball at hairline

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Follow through

Follow through is not widely discussed but is generally recommended to be in the direction of the target in some cases, the head is thrust towards the target.

torso and head motion continues immediately after contact and then decelerates to regain balance

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Soccer throwing-in 13 14

Only twice in the game of soccer is a player, other than the goalkeeper, allowed to touch the ball with their hands. One is during dead-ball situations to set a free kick; the other is a throw-in.

Since a throw-in is the time when a player is actually able to propel the ball with his hands, it is key that they are able to throw the ball with velocity and accuracy, since the greater the velocity the greater the chance to achieve maximum range.

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Types of throwing in

There are two types of throw-ins that a player can perform legally since both feet must touch the ground.

standing throw-in. running throw-in. The running throw-in and standing

throw-in are very contrasting. They do have the same arm movements, but are very different in which the trunk and lower extremvities move.

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The standing throw-in

The standing throw-in starts with both feet on the ground, and never leaving the ground.

The knees then flex as the arms bring the ball back overhead. When the ball starts to go behind the head, the hips start to hyperextend.

When the ball reaches as far back as it can go, the arms extend, bringing the ball overhead, while the trunk flexes and the knees extend.

The movement ends when the ball is released from the hands.

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The standing throw-in cont..

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The running throw-in

The running throw-in actually starts about a meter and a half from the line.

The player runs to the line and while running brings the ball behind the head. When the dominant leg reaches the line and plants, the arms then extend bringing the ball back overhead and releasing the ball when it is at the highest point.

The feet are not next to each other, one is posterior to the other.

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Running throw-in cont..ESPT India

 Angular Kinematics

Segment Angle. The forearm segment angles fairly similar in

both the running (-108 deg.) and standing (-111 deg.) throw-ins.

The range of motion in the running throw-in (85 deg.) is less than the standing throw-in (115 deg.).

The point of release the standing throw-in had a point of release of

4 deg., the running throw-in had a point of release of

–23 deg. .

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Joint angle

Joint Angle 1.- The knee joint angles were remarkably similar in each of the movements. The ranges of motion for the knee = 9 degrees. the maximum flexion and extension angles differed.

The running throw-in produced a maximum extension angle of 147 deg., and a maximum flexion angle of 138 deg.

The standing throw-in produced a maximum extension angle of 160 deg., and a maximum flexion angle of 151 deg.

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Joint angle cont..

Joint Angle 2. The hip joint angles were distinctively different .

The range of motion differed by 34 degrees (running = 7deg.; standing = 41 deg.).

This difference in range of motion resulted in variations between the maximum flexion and extension angles.

The maximum flexion angle for the running throw-in was 228 deg and had a maximum extension angle of 221 deg.

While the standing throw-in produced a maximum flexion angle of 196 deg, and a maximum extension angle of 155 deg.

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Joint Velocity

The velocity patterns for the running throw-in and standing throw-in are almost similar .

Despite the similarity, the maximum flexion and extension angular velocities of the hand are different.

The maximum flexion angular velocity of the hand in the running throw-in was –217deg/sec, and the maximum extension angular velocity was 2333 deg/sec.

The standing throw-in produced a maximum flexion angular velocity of –433 deg/sec, and a maximum extension angular velocity of 2267 deg/sec..

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To Pass To Shoot To Chip

Where to Approach the Ball

Slightly off straight on

45 degree angle

45 degree angle

Where to Keep Your Eyes Find your Target…then.. EYES ON THE BALL

Where to Plant Your Foot, etc

Plant Foot Next to Ball. Don’t reach for the ball.

Hips and Shoulders square to the target.

Where Planted Foot Should Point Pointing at the Target…knee slightly bent

How Your Ankle Should be Locked Locked Up,

Rigid

Locked Down …Toes Pointed

Down… Rigid

Short Chip – Locked Up

Long Chip – Locked Down

Where Your Knee Should Be

Equal with the Ball

Over the Ball Slightly Behind the ball

Passing, shooting and chipping 13

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Passing ,shooting and chipping

To Pass To Shoot To Chip

Which part of Foot Should Kick the

Ball

Side of Foot,(between toe and

heel)

Instep Instep

Where to Strike the Ball

Above the Equator

At the Equator

Short Chip – Under the

Ball.Long Chip-

Below the Equator.

How You Should Follow Through

Square Finish…

body weight over the ball

Aggressively Through the Ball –Transfer Weight

Minimal Follow

Through..Hold back on the

follow thru

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The causative mechanisms of specific soccer injuries

Footballer’s ankle Ankle sprains ACL injury Shin splints and anterior tibial

compartment syndrome Hamstring strain The groin injury and adductor

strain

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Footballer's Ankle

The condition is a chronic periostitis or peritendinitis with calcification which may occur on the anterior margin of the lower end of the tibia

It is owing to the way in which the player ordinarily kicks the ball with the foot in plantar-flexion with slight inversion. The ball making contact with the dorsal and medial aspect of the foot.

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Ankle sprains

Ankle sprains are the most common injury amongst all levels of soccer player and account for a massive 36% of all injuries.

This injury is most commonly sustained when running and changing direction quickly, or when tackling or being tackled.

An inversion (lateral) sprain of the ankle occurs when the ankle is rolled over so that the sole of the foot faces inwards.

Eversion (medial) sprains are far less common

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ACL INJURY

The ACL is the anterior cruciate ligament which is one of the most frequently damaged ligaments in the game of soccer.

The majority of these injuries occur in a non-contact situation at a point where the player lands or decelerates with a twisting motion.

The player usually experiences an audible “popping” sound, or a feeling of the knee “giving way” or swelling.

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Mechanism of injury to the ACL

The typical mechanism of injury for the ACL during soccer is where the athlete’s leg is in a forced valgus position (often in a contact tackle situation) during which the knee is axed and there is a degree of internal rotation of the femur on an externally rotated tibia, which is axed to the ground by the soccer boot.

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Mechanism of acl injury cont..

In addition, the ACL can easily be torn when the leg is positioned in severe hyperextension and the force of another player causes the hyperextension to go beyond that normally allowed by the knee joint (i.e., causing excessive anterior translation of the tibia with respect to the femur).

Combine these positions with sudden deceleration and any degree of internal or external rotation on a axed foot (usually because of the studs or bars in the soccer boot) and the ligament is susceptible to partial or complete rupture.

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Shin splint and anterior tibial compartment syndrome.

Pain along the medial half distal border of tibia is some time encounter.

It is usually a periostitis Pain swelling and limping are main symptoms Shin splints may occur due to hit on the shin by

other player and by prolonged running Anterior tibia compartment syndrome has been

reported in soccer player which may also be produced by the kick from another player or results from running.

It may be one of the complication of shin splints.

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Hamstring strain

The hamstrings are the most commonly torn muscles in soccer

A tear to one of the hamstring muscles most often occurs during a burst of speed especially in muscles which are either fatigued or have been inadequately warmed-up

One of the mechanism hamstring got torn is sudden powerful kick with hip in full flexion and knee in full extension.

Prolonged running and fatigue might another cause of hamstring stain in soccer player.

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Groin injury

Since soccer player manipulate the ball with their legs, groin injuries are fairly common

These are caused by sudden powerful overstretching of the leg and thigh in abduction and external rotation especially if there is an opposing force such as wet heavy ball, an opponent foot at full speed and in full swing, or the ground.

These forces may overstretch the fiber of muscle or tendon, the bony tissue of the pelvic ring and the pubic symphysis.

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Groin injury cont…

Adolescent soccer player may sustain avulsion fracture of the pelvic apophysis.

groin pain also occur as an overuse syndrome that begins with adductor strain, leading first to tendinitis followed by chondritis, ostitis and formation of necrotic foci in pubis or as attached muscle appearing as a calcifying tendinitis.

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References

1. Barfield, B (1998), The biomechanics of kicking in soccer. Clinics in Sports Medicine. 17(4): 711-728.

2. Phillips, S (1985), Invariance between segments during a kicking motion. In Matsui, H, and Kobayashi, K (eds), Biomechanics. Human Kinetics: Illinois. pp 688-694.

3. Isokawa, M, and Lees, A (1988), A biomechanical analysis of the in-step kick motion in soccer. In Reilly, T, and Williams, M, (2003), Science and Soccer (2nd ed). Routledge: London. pp. 449-455.

4. Abo-Abdo, H (1981), unpublished doctoral dissertation. In Barfield, B (1998), The biomechanics of kicking in soccer. Clinics in Sports Medicine. 17(4): 711-728.

5. Hay, J (1996), Biomechanics of Sport Techniques. Prentice Hall: New Jersey.

6. Ben-Sira, D (1980), A comparison of the instep kick between novices and elites. In Barfield, B (1998), The biomechanics of kicking in soccer. Clinics in Sports Medicine. 17(4): 711-728.

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7wych, W. (1979), The Official Soccer Book of the United States Soccer Federation. In Barfield, B (1998), The biomechanics of kicking in soccer. Clinics in Sports Medicine. 17(4): 711-728

8Wahrenburg, H, Lindbeck, J, aChysond Ekholm, J (1978), Knee muscular moment, tendon tension force and EMG during a vigorous movement in man. Scand J RehabMed. 10:99-106.

9De Proft, E, Cabri, J, and Dufour, W (1988), Strength training and kick performance in soccer players. In Reilly, T, and Williams, M. 2003), Science and Soccer (2nd ed). Routledge: Londo.

10 Plagenhoff, S. (1971), Patterns of Human Motion. A Cinematographic Analysis. Prentice-Hall: New Jersey.

11Gainor, B, Pitrowski, G, and Puhl, J (1978), The kick. Biomechanics and collision injury. Am J Sports Med.6:185-193

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Question…….?

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Thank you

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