RELATIONSHIP BETWEEN ENERGY DEFICITS AND BODY COMPOSITION IN ELITE FEMALE GYMNASTS AND RUNNERS

Abstract

1927 This study evaluated energy balance and body composition in 42 gymnasts([horizontal bar over]x age=15.5 yr.) and 20 runners ([horizontal bar over]x age=26.6 yr.), all of whom were on national teams or nationality ranked. Athletes were assessed for body composition using DEXA and skinfolds, and energy balance was determined with a Computerized Time-Line Energy Analysis(CTLEA) procedure. Results from the CTLEA were assessed as the number of within-day energy deficits (largest and frequency), and within-day energy surpluses (largest and frequency). The [horizontal bar over]x hourly energy deficits > 300 kcal was 9.45 (±6.00) for gymnasts, and 3.70(±5.34) for runners. The [horizontal bar over]x largest daily energy deficit was 743 (±392) kcal for gymnasts, and 435 (±340) kcal for runners. The [horizontal bar over]x number of hourly energy surpluses > 300 kcal was 1.40 (±3.04) for gymnasts, and 6.20 (± 5.50) for runners. The [horizontal bar over]x largest daily energy surplus was 239(±219) kcal for gymnasts, and 536 (±340) kcal for runners. There was a significant relationship between the number of daily energy deficits> 300 kcal and DEXA-derived body fat% in gymnasts (r=.508; p=.001) and for runners (r=.461; p<.041). There was also a negative relationship between the largest daily energy surplus and DEXA-derived body fat percentage for gymnasts (r=-.418; p<.003). Body weight and the number of hourly energy deficits > 300 kcal were the only variables to explain a significant amount of variance (p=.000) in body fat percentage using a forward stepwise regression procedure. These data suggest that within-day energy balance is a predictor of body fat percentage in anaerobic and aerobic elite athletes, and that the adaptive response to energy deficits may be greater than the response to energy surpluses in these groups of athletes.