Effects of Different Jumping Programs on Hip Bone Mineral Density in Premenopausal Women
STUDENT ONE (All caps indicates the presenting author)
Department of Physical Therapy
Briar Cliff University
Department of Exercise Sciences
Brigham Young University
This will be a 15-minute oral presentation. 5 minutes will be provided or questions and answers.
RESEARCH QUESTION: The purpose of this research was to determine the effects of two different jumping protocols on percent change in bone mineral density (BMD) at the hip compared to a control group. Secondary objectives were to determine if percent changes in hip BMD were independent of age, changes in body weight, calcium intake, ground reaction force, and activity compliance within the sample.
BACKGROUND: Every year over 300,000 hip fractures occur due to osteoporosis. As we age we all lose bone density (BMD). However, women, at the commencement of menopause, lose bone density at an accelerated rate. This increased loss further increases the risk for osteoporotic fractures.
METHODS: Sixty premenopausal women (age 25-50) finished a 16-week randomized controlled trial. Subjects were randomly assigned to a control group or one of two jumping groups. The Jump 10 group performed 10 jumps with 30 seconds of rest between jumps, twice daily, while the Jump 20 group performed the same protocol but with 20 jumps. All assigned activities were completed in the subjects’ homes.
RESULTS: At 8 weeks, BMD percent change at the hip was significantly different among groups when age, weight change, and subject compliance were simultaneously adjusted. In particular, the Jump 20 group had a greater percent change in hip BMD compared to controls. Following 16 weeks of jumping, BMD percent change at the hip was significantly different among groups after adjusting for all covariates. Specifically, at the hip, the Jump 10 and Jump 20 groups showed significantly greater percent change in BMD compared to controls. Within-group analyses revealed no significant changes from baseline to 16 weeks for the jumping groups, but controls lost significant BMD.
CONCLUSION: After 16 weeks of high-impact jump training, BMD at the hip can be improved by jumping 10 or 20 times, twice daily, with 30 seconds of rest between each jump, compared to controls.