Influence of peak strain on lumbar bone mineral density: An analysis of 15-year physical activity in young males and females

In 83 males and 99 females, the relation between peak strain physical activity (PSPA) from 13 to 27 years and lumbar bone mineral density (LBMD) at age 27 was studied. Physical activity was measured longitudinally by an interview six times between ages 13 and 27. Peak strain scores based on ground reaction forces were developed to quantify all registrated activities for peak strain. LBMD was determined once at age 27. Four PSPA periods were considered: the teenage period (13-17 years), the period between 13 and 21 years, the adult period (21-27 years), and the total period (13-27 years). In multiple linear regression analyses, with body weight and gender as covariates, PSPA appeared to be a significant positive predictor for LBMD at age 27 in both males and females for all analyzed periods. The explained variance of PSPA for LBMD was the highest (25%) for the total period and the lowest (8%) for the teenage period.