Jumping and other warm-up activities contribute to stronger bones

High-impact activities such as jumping and skipping that can easily be incorporated into warm-ups before sports and physical education classes have been shown to benefit bone health in adolescents.

In a recent Australian study, the 10-minute school-based intervention, which was provided twice a week for about 8 months, significantly improved bone and muscle strength in healthy teenagers compared to regular warm-ups.

In a press release, physiotherapist Benjamin K. Weeks, PhD, said the warm-up, which included tuck jumps, star jumps, side lunges and skipping with gradually increasing complexity and repetitions, was specifically designed to apply a bone-stimulating mechanical load on the skeleton. Students worked up to about 300 jumps per session by the end of the study.

“Eighty percent of bone mass is accrued in the first 20 years and especially around puberty due to the circulating hormones,” he said in the press release. “This study targets a window of opportunity in adolescence to maximize peak bone mass with high-intensity, weight-bearing activity.”

Findings from the study of 99 adolescents with a mean age of almost 14 years indicate that boys in the intervention group improved whole body bone mass while the girls? bone mass specifically improved at the hip and spine. Boys in the bone-friendly warm-up group also lost significantly more fat mass than the other boys, according to the press release.

A member of the Bone, Muscle and Movement Group at the Griffith Institute of Health and Medical Research in Gold Coast, Australia, Weeks said the gender-specific response to the exercise program may be related to the different rates of physical development, with girls reaching maturity at an earlier age than boys.

“Peak height velocity is at different ages in boys and girls. Most boys in the group were right at that stage while most girls in the study were past puberty,” he said in the press release.

Weeks said the improved bone strength recorded at the hip and spine in girls is promising because those are the typical sites for osteoporotic fractures in the elderly.

While the study showed that a simple, practical exercise intervention can result in worthwhile skeletal benefits in adolescents, Weeks said larger, longitudinal studies are required to determine whether the beneficial effects can persist into adulthood and reduce the risk of future bone fractures.

For more information:
Weeks BK, Young CM, Beck BR, Eight months of regular in-school jumping improves indices of bone strength in adolescent boys and girls: The POWER PE Study. J Bone Min Research. 2008;23(7):1002-11.