Long-term recreational gymnastics, estrogen use, and selected risk factorsfor osteoporotic fractures

The purpose of this cross-sectional study was to examine whether long-term participation in recreational gymnastics or folk dancing or estrogen replac ement therapy (ERT) is associated with mechanically more competent bones an d improved muscular strength and body balance. One hundred and seventeen he althy, female postmenopausal recreational gymnasts (mean age 62.1 [SD 4.7] years) and 116 sedentary controls (mean age 61.5 [4.6] Sears) were enrolled in the study. Bone mineral content (BMC) of the distal radius, femoral nec k, and trochanter were measured with dual-energy X-ray absorptiometry. BMC of the midshaft and distal tibia and trabecular density (TrD) of the distal tibia were measured with peripheral computed quantitative tomography. Maxi mal isometric strength, muscular power, cardiorespiratory fitness, and body balance of the participants were also assessed. The cardiorespiratory fitn ess, muscular strength, and dynamic balance of the recreational gymnasts an d folk dancers combined were significantly better than those of the control s, the average group difference ranging from 7.5% (95% confidence interval 5.0-9.9%) in dynamic balance to 12.8% (6.6-19.4%) in dynamic muscular power . ERT was not associated with the fitness indicators, muscular power, or ba lance, but was significantly associated with the BMC at all the measured bo ne sites, the mean group difference between estrogen users and nonusers ran ging from 6.5% (3.7-9.3%) for the tibial shaft to 11.8% (6.4-17.0%) for the distal radius. Recreational gymnastics, in turn, was significantly associa ted with higher BMC at the tibia only, the mean group difference being 3.9% (0.9-6.9%) for the tibial shaft and 7.7% (3.7-11.9%) for the distal tibia. Recreational gymnastics was also associated with higher TrD at the distal tibia (5.2%; 1.2-9.2%), whereas estrogen usage did not show such associatio n. The results indicate that ERT seems especially effective in preventing p ostmenopausal bone loss, whereas recreational gymnastics and folk dancing i mprove muscular performance and body balance in addition to increased bone mass and bone size in the tibia. All these factors are essential in prevent ion of fall-related fractures of the elderly.