Spotlight on Research 2008

November 2008 (historical)

Simple Exercise in Children Yields Long-Term Skeletal Benefit

Recent studies funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) have shown that jumping exercises for just one school year in early childhood can trigger increases in bone mineral density (BMD) that are sustained for several years. The studies demonstrate the value of even simple high impact activities - like jumping - on BMD, while providing added support for the notion that the bone mass attained in youth can be an important determinant of lifelong skeletal health.

NIAMS researcher Christine Snow, Ph.D., and her colleagues at Oregon State University tested the effects of a school-based exercise intervention on the BMD of pre-pubertal children. The studies focused on follow-up of children enrolled in the Building Growing Skeleton in Youth (BUGSY) program.

Children enrolled in the BUGSY program were assigned to one of two groups for a single school year. Children in the intervention group performed a series of 100 consecutive jumps off of a two-foot high box three days a week. Children in the control group participated in a standard physical education program without the jumping regimen.

Snow and her colleagues followed one set of 57 study participants for eight years after a single school year of jumping exercises. They found that children in the jumping group had sustained significant gains in BMD at the eight-year mark, although the differences between groups were not as great as immediately after the intervention. Another set of 100 children followed for four years demonstrated that those in the jumping intervention had 2 to 4 percent greater BMD than those in the standard physical education program.

It is well known that physical activities that load (stress) the skeleton are the most beneficial for bone density, especially those that place levels of loading on bone that are greater than those seen in everyday activities. The jumping regimen used in Snow's intervention produced a force of 3.5 times the child's body weight on the bones of each leg.

Assuming that such gains in BMD are sustained when bone mass peaks in early adulthood, Snow and her team may have identified a strategy in youth that could reduce the risk of osteoporosis and fractures later in life. Says Snow, "True to our hypothesis, low repetition, high impact exercise of only seven months applied prior to puberty stimulated a persistent bone response. Therefore, in the growing skeleton, we believe that there is both an optimal time and an optimal exercise program to promote skeletal strength." Moreover, a program continued throughout the school years may optimize and solidify the gains seen in these short term studies.

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases, a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov. Information on osteoporosis and other bone disorders is available from the NIH Osteoporosis and Related Bone Diseases~National Resource Center; phone toll-free 800-624-BONE (2663), or visit www.niams.nih.gov/bone.

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Gunter KB, Baxter-Jones AD, Mirwald RL, Almstedt H, Fuchs RK, Durski S, Snow C. Impact Exercise Increases BMC During Growth: An 8-Year Longitudinal Study. J Bone Miner Res. 2007 Dec 11. [Epub ahead of print]. PMID: 18072874.

Gunter K, Baxter-Jones AD, Mirwald RL, Almstedt H, Fuller A, Durski S, Snow C. Jump starting skeletal health: a 4-year longitudinal study assessing the effects of jumping on skeletal development in pre and circum pubertal children. Bone. 2008 Apr;42(4):710-18. Epub 2008 Jan 18. PMID: 18282755.