We studied 91 healthy premenopausal women aged 20-39 years old to investigate the effect of teenage physical activities on their current bone mineral densities (BMD). Whole body BMD (WBMD), lumbar BMD (LBMD) and radial BMD (RBMD) were measured with Dual energy X-ray absorptiometry (DEXA). Physical activities during junior high school, senior high school, at present ; and food consumption were surveyed using a questionnaire. After adjusting for age, BMI, current calcium intakes, and teenage milk intake ; subjects who exercised one or more hours per week as extracurricular activities at junior or senior high school had significantly higher BMD at all sites (p<0.01) than those who exercised less. Subjects who played high impact sports at all periods had significantly higher WBMD (p<0.01) than subjects who played lowimpact sports. Subjects who played high impact sports at junior high school had significantly higher LBMD than their low-impact sports counterparts (p<0.01). Subjects with continuous exercise from teenage years to the present had significantly higher BMD at all sites than other subjects after adjusting for potential confounders (p<0.001 in WBMD, P<0.01 in LBMD and p<0.05 in RBMD). In the stepwise multiple linear regression analysis, BMI and high-impact sports at senior high school were independent predictors of WBMD, and BMI and high-impact sports at junior high school were independent predictors of LBMD. Our data suggests that continuous high-impact exercise from junior high school may maintain a positive effect on current bone mass.

DESCENTE SPORTS SCIENCE Vol.21/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE