Estimates of Energy Expenditure During Swimming Utilizing an Omnidirectional Accelerometer

1. Estimates of Energy Expenditure During Swimming Utilizing an Omnidirectional Accelerometer Jeanne D. Johnston and Joel M. Stager, FACSM Counsilman Center for the Science of Swimming Human Performance Laboratory Department of Kinesiology, Indiana University, Bloomington, IN

2. Liljestrand & Stenstrom, 1920

3. Current Methods to Estimate the Energy Expenditure of Swimming • Published tables • Regression equations developed using oxygen consumption and swimming velocity • Indirect calorimetry

4. 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

5. 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

6. 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.

7. 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 (kcalkg-1min-1)

8. Results • There were significant correlations between the linear acceleration of limbs (ODA counts) and oxygen uptake. • Degree of correlation depends on sex of subject Correlation Significant at .01**, .05* (2-tailed)

10. R2 = 0.72, SEE = .0333 kcalkg-1min-1 R2= 0.62, SEE = .0432 kcalkg-1min-1

11. 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

12. 2X400FS 2X200 Pull 5X50/10X50 Rest 18X100 Kick Cool 2X300BK 2x100 IMFly, Back, Breast, FS on 45 Down

13. 2X400FS 2X200 Pull 5X50/10X50 Rest 18X100 Kick Cool 2X300BK 2x100 IM Fly, Back, Breast, FS on 45 Down

15. 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.

16. 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.

17. 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

18. Acknowledgements • United States Master Swimming • Mini-Mitter Corporation, Bend, Oregon • Indiana University Women’s Swimming • Graduate Students • Jeff Web • Colleen McCracken • Franny Benay