Estimates of Energy Expenditure During Swimming Utilizing an

Omnidirectional Accelerometer

Jeanne D. Johnston and Joel M. Stager, FACSMCounsilman Center for the Science of Swimming

Human Performance LaboratoryDepartment of Kinesiology, Indiana University,

Bloomington, IN

Liljestrand & Stenstrom, 1920

Current Methods to Estimate the Energy Expenditure of Swimming Published tables

Regression equations developed using oxygen consumption and swimming velocity

Indirect calorimetry

Energy Balance of Swimmers

Primarily collegiate swimmers High intensity, long distance, interval, taper Swimming energy expenditure

4300-8,970 meters/day 732-2293 kcal per training session

Total Daily Expenditure Methods: Caloric intake, Doubly labeled water

(Jones and Leitch, 1993;Trappe, et al., 1997) 6,000-17,500 meters/day; 2,622-5593 kcals/day

Accelerometry

Based on the assumption that limb movement and body acceleration are proportional to the muscular forces responsible for the accelerations (Bouten, et al., 1996).

Actical (Mini-Mitter Corporation) is an omnidirectional accelerometer measuring 37x29x9 mm and weighing 17 grams

Dependent on the orientation of the accelerometer

Does not measure acceleration perpendicular to the primary axis

Purpose

Evaluate the efficacy of an omnidirectional accelerometer (ODA) to quantify swimming energy expenditure (SWE) and assess overall swim training dosage.

Phase I: Generation of an algorithm for SWE from ODA output

Phase II: Monitor collegiate practice to quantify training dosage.

Methods

Eight men (26.5 years, +/-8.8) and 10 women (27.1 years, +/-9.8)

400 yard front crawl swims (light, moderate, and hard intensity)

Swimming velocity .82-1.51 m·sec-1 An ODA was worn on the right wrist, waist, and

right leg Expired gases were collected for 20 seconds at

the completion of each swim Multiple regression techniques were utilized to

develop the algorithm for SWE (kcalkg-1min-1)

Results

There were significant correlations between the linear acceleration of limbs (ODA counts) and oxygen uptake.

Degree of correlation depends on sex of subject

Arm Leg Waist

Male .345 .820** .431*

Female .741** .421* .231

Correlation Significant at .01**, .05* (2-tailed)

Figure 1: Average ODA Output for Males at Light, Moderate, and Hard Intensity

0

2000

4000

6000

8000

10000

12000

Light Moderate Hard

Intensity of 400 Yard Swim

Av

era

ge

O

DA

Ou

tpu

t (C

ou

nts

/Min

ute

)

Arm

Leg

Waist

Figure 2: Average ODA Output for Females at Light, Moderate, and Hard Intensity

0

2000

4000

6000

8000

10000

12000

Light Moderate Hard

Intensity of 400 Yard Swim

Av

era

ge

OD

A O

utp

ut

(Co

un

ts/M

inu

te)

Arm

Leg

Waist

Figure 3. SWE Predicted from ODA Leg Counts, Age and Height (Males)

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 0.02 0.04 0.06 0.08 0.1 0.12

Measured Energy Expenditure (kcal/kg/min)

Pre

dic

ted

En

erg

y E

xpen

dit

ure

(kc

al/k

g/m

in)

Figure 4. SWE Predicted from ODA Counts, Age, and Height (Females)

0

0.05

0.1

0.15

0.2

0.25

0.3

0 0.05 0.1 0.15 0.2 0.25 0.3

Measured Energy Expenditure (kcal/kg/min)

Pre

dic

ted

En

erg

y

Ex

pe

nd

itu

re (

kc

al/k

g/m

in)

R2 = 0.72, SEE = .0333 kcalkg-1min-1

R2= 0.62, SEE = .0432 kcalkg-1min-1

Phase II: Training Dose

Purpose: Utilize the accelerometer output to quantify “physiological load” of a workout set, workout, and or weekly training plan.

Methods Two female collegiate Monitored 3 days of swim practice Accelerometers were worn on their wrist and ankle Heart rate was recorded throughout practice

Practices varied in time, distance swam, and intensity

Leg Acceleromter Counts (Day2/Subject1)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Acc

eler

om

eter

Co

un

ts/1

5 S

eco

nd

s)

2X400FS 2X200 Pull 5X50/10X50 Rest 18X100 Kick Cool

2X300BK 2x100 IM Fly, Back, Breast, FS on 45 Down

Arm Acceleromter Counts (Day2/Subject1)

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Acc

eler

om

eter

Co

un

ts/1

5 S

ec

2X400FS 2X200 Pull 5X50/10X50 Rest 18X100 Kick Cool2X300BK 2x100 IM Fly, Back, Breast, FS on 45 Down

Day 1

0

1000

2000

3000

4000

5000

6000

7000

Time (minutes)

Co

un

ts/1

5 S

eco

nd

sDay 2

0

1000

2000

3000

4000

5000

6000

7000

0:00

0:10

0:20

0:30

0:40

0:50

1:00

1:10

1:20

1:30

1:40

1:50

2:00

Time (minutes)

Co

un

ts/1

5 se

c

Day 3

0

1000

2000

3000

4000

5000

6000

7000

Time (minutes)

Co

un

ts/1

5 se

c

Breakdown of Day 2 Swim Practice

58%27%

5%

10%

Sw im

Kick

Pull

Rest

Conclusions

ODA may provide a means to quantify daily or weekly energy expenditure allowing for the examination of energy balance of the athlete.

ODA may provide a means of quantifying a workout or series of workouts

ODA may allow for evaluation of the relative “load” that a segment or cumulative training plan might represent.

Provides insight into the intensity, repetition and time of a workout.

Potential Applications

Evaluation of the contribution of leg and arm separately

Quantification of total swim effort and rest time.

Monitor stroke technique based on observed insufficient arm or leg counts

Assessment of inter-individual practice effort.

Future Applications

• Kcals/minute or total kcals per session

• Establish cut-off points based on total counts/session for light, moderate and hard training session

ArmCts/min

LegCts/min

Arm& Leg

Cts/min

Arm & Leg

Cts/Meter

TotalCounts

Distance Description

Day 1

4984 9339 14383 506 1226146 2,424 ShortIntense

Day 2

5676 9129 14805 253 1821043 7,200 LongIntense

Day 3

3687 8225 11912 229 1372858 5,990 ModerateModerate

Acknowledgements

United States Master Swimming Mini-Mitter Corporation, Bend, Oregon Indiana University Women’s Swimming Graduate Students

Jeff Web Colleen McCracken Franny Benay