Relationship between indicators of fitness and bone density in adolescent Brazilian children.

The purpose of the current study was to investigate the relationship between health-related physical fitness and bone mineral density (BMD) in adolescents. One hundred forty-four adolescents (65 boys and 79 girls) between 15 and 18 years of age were recruited to this cross-sectional study. Subjects were evaluated in aerobic fitness, muscular fitness, flexibility, body composition, and maturation. BMD of the lumbar spine, total body, and proximal femur were measured by a dual-energy X-ray absorptionmeter. Pearson's correlation and stepwise multiple regression analyses were used (p < .05). Lean body mass (LBM) and abdominal muscular fitness explained 35-40% of proximal femur BMD in whole group and boys' total body BMD (43%); however, VO2max and LBM predicted girls' total body BMD (23%). Lumbar spine BMD was predicted only by LBM for both genders (18% boys, 15% girls). In summary, lean body mass is the main predictor of bone mass during the end of adolescence, regardless of gender, whereas muscular fitness contributes more to bone mass among males than among females.