Relationships between physical activity and physical capacity in adolescent females and bone mass in adulthood

This study investigates whether physical activity and physical performance in adolescence are positively related to adult bone mineral density (BMD). In 1974, physical activity, endurance, and muscular strength were measured in 204 randomly selected female students, age 16.1 +/- 0.3 year (range 15-17 years). Twenty years later, 36 of the women volunteered to undergo a measurement of their BNID. Women who were members in a sports club in adolescence had significantly higher adult BNID (mean differences of 5% to 17% depending on site) compared with subjects who were not engaged in a sports club. Furthermore, women with persistent weight-bearing activity in adulthood had significantly higher BMD compared with women who had stopped being active or had never been active. The differences ranged between 5% and 19% with the highest difference found in trochanter BNID. Stepwise regression analyses showed that membership in a sports club at baseline was a significant independent predictor of BNID in the total body, lumbar spine, legs, trochanter, and femoral neck, explaining 17-26% of the variation in BNID. Change in body weight was a strong independent predictor of BMD of the total body and arms, explaining 8% of the variation in both sites. In addition, running performance at baseline was an independent predictor of total body BNID, whereas the two-hand lift performance significantly predicted BMD of the total body, legs and trochanter. The hanging leg-lift and handgrip were both significant predictors of arm BNID. In conclusion, membership in a sports club and site-specific physical performance in adolescence together with the change in body weight were significantly associated with adult BMD in premenopausal women.