Bone, growth, and dietary intake in premenarcheal female gymnasts

Uncertainty exists as to if child gymnasts possess higher bone mineral density (BMD), have stunted growth and restricted diets compared to age-, height-, and weight-matched nongymnast controls and if gymnastics training impacts BMD, growth, and dietary intake in young girls. Thus, BMD, growth, and dietary intake variables were investigated in premenarcheal gymnasts compared to matched nongymnast controls. Additionally, body composition, physical activity, energy expenditure, and biochemical markers of bone tumover were examined. Gymnasts possessed significantly higher BMD at the total proximal femur (TPF), femoral neck (FN), trochanter (Troch). Ward's triangle, and lumbar spine (LS), but not whole body (WB). Gymnasts possessed significantly lower fat mass (FM) and percent body fat (% BF) compared to controls and engaged in significantly more hours of very hard activity, thus, expending significantly more energy than controls. Mean daily dietary intakes of kilocalories, protein, carbohydrate, and fat were not significantly different in gymnasts versus controls. Over one year, female child gymnasts continued to possess significantly higher BMD at all body sites and had moderate gains in FN, Troch, LS, and WB BMD in gymnasts compared to controls despite a significant decrease in the % Adequate Intake of dietary calcium consumed. Significantly lower % BF in gymnasts versus controls was observed at all time points, and gymnasts continued to engage in significantly more hours of very hard activity. A significant decrease in urinary pyridinium cross-links was observed in a subset of both gymnasts and controls from baseline to 6-months. Lastly, both gymnasts and controls had significant increases in height, weight, body mass index, % target height, growth velocity, fat-free soft tissue mass, FM, and bone area at the TPF, FN, LS, and WB during one year of study. Gymnasts did not differ in their pattern of growth when compared to controls. Participation in artistic gymnastics activity contributes to attainment of peak BMD in young females. Importantly, participation in artistic gymnastics at a competitive but nonelite level of bone from age 10 to 11 years.