Changes In Body Composition And Energy Balance In Collegiate Female Gymnasts Over Multiple Competitive Seasons

Abstract

The maintenance of energy status is an important dietary goal for competing athletes to properly fuel efforts, promote recovery, and prevent onset of illness or decrements in performance. Recent work in competing male athletes has reported on energy balance using body-composition derived parameters, but limited data is available highlighting changes in female athletes, and in particular female athletes who participate in physique sports. PURPOSE: To assess the changes in body composition and energy balance in female collegiate gymnasts over multiple competitive seasons. METHODS: 19 NCAA Division II collegiate female gymnasts (Mean ± SD; 18.4 ± 0.68 yr, 59.4 ± 4.5 kg, 160.9 ± 5.4 cm, 22.6 ± 2.2 % fat, 18.0±1.2 kg/m2 fat free mass index) underwent dual-energy x-ray absorptiometry (DEXA) scans at the start of each season. Data was collected on all 19 subjects over three years with nine subjects being extended to a fourth year. Energy balance (EB) was calculated using a previously validated equation (EB= 1.0(Δ FFM/Δ Time) + 9.5(Δ FM/Δ Time) using fat free mass (FFM), time (days between scans) and fat mass (FM). A factorial ANOVA with repeated measures on time was conducted for changes in FFMI and Δ EB. Individual paired samples T-Tests were conducted when significance was found. RESULTS: Significant differences (p<0.05) between EB at year 1 (26.1 ± 46.7 kcals/day) and year 2 (-20.3 ± 57.9 kcals/day). Differences were also found (p<0.05) between years 2 (-20.3 ± 57.9 kcals/day) and year 3 (48.9±59.7) among the 9 subjects whose data extended to a fourth scan. No statistical significance was found (p > 0.05) between FFMI levels between year 1 (18.0 ± 1.2 kg/m2), year 2 (18.1 ± 0.8 kg/m2), and year 3 (18.3 ± 1.3 kg/m2). CONCLUSION: Changes in energy balance were largely stable in competitive female gymnasts across three years periods of time. Additionally and in concert, FFMI levels were also found to be stable across the measurement period. While statistically significant differences were present, the practical significance of these differences is not deemed to be relevant. Additional research is needed in all female athlete population to help identify and understand what dietary changes may be needed to best promote health, performance, and recovery.