Augmented trochanteric bone mineral density after modified physical education classes: A randomized school-based exercise intervention study in prepubescent and early pubescent children

Background: Of the few exercise intervention studies focusing on pediatric populations, none have confined the intervention to the scheduled physical education curriculum. Objective: To examine the effect of an 8-month school-based jumping program on the change in areal bone mineral density (aBMD), in grams per square ce ntimeter, of healthy third- and fourth-grade children. Study design: Ten elementary schools were randomized to exercise (n = 63) a nd control groups (n = 81). Exercise groups did 10 tuck jumps 3 times weekl y and incorporated jumping, hopping, and skipping unto twice weekly physica l education classes. Control groups did regular physical education classes. At baseline and after 8 months of intervention, we measured aBMD and lean and fat mass by dual-energy x-ray absorptiometry (Hologic QDR-4500). Calciu m intake, physical activity, and maturity were estimated by questionnaire. Results: The exercise group showed significantly greater change in femoral trochanteric aBMD (4.4% vs 3.2%; P < .05). There were no group differences at other sites. Results were similar after controlling for covariates (base line aBMD change in height, change in lean, calcium, physical activity, sex , and ethnicity) in hierarchical regression. Conclusions: An easily implemented school-based jumping intervention augmen ts aBMD at the trochanteric region in the prepubertal and early pubertal sk eleton.