Exercise‐induced training effects on bone mineral content: a 7‐year follow‐up study with adolescent female gymnasts and runners

The objective of this study was to assess differences in the effects of competitive gymnastics and running on bone mineral content (BMC) of the lumbar spine and femoral neck when compared with their non‐competing age‐matched controls. Caucasian healthy peri‐pubertal girls (52 competing gymnasts, 46 competing runners, 44 non‐athletic controls) were included. Weight, height, and type and amount of exercise (MET h/week) as well as BMC of the lumbar spine and femoral neck were measured repeatedly. Statistical comparisons between groups were made using ANOVA. Repeated measures were analyzed using generalized linear mixed models. The median MET value of gymnasts was significantly higher when compared with runners and controls at baseline, P=0.001. The weekly median MET hours decreased during the follow‐up. The mean (adjusted for height, weight, and years from menarche in the 7‐year follow‐up) BMC of the lumbar spine and femoral neck was significantly higher among gymnasts when compared with the other two groups. Group‐by‐time interaction was significant only at the femoral neck (P=0.048). The type of physical activity was a significant factor in BMC of the adolescent women. Gymnasts had greater BMC at lumbar spine and femoral neck during the total 7‐year follow‐up period when compared with runners and controls.