A meta-analysis of brief high-impact exercises for enhancing bone health in premenopausal women

Exercise is considered an important means of improving bone health and preventing osteoporosis. Brief bouts of simple exercises may be useful for aiding lifestyle compliance to physical activity. The aim of this study was to review the evidence on the effect of brief, high-impact exercise on bone health among premenopausal women. Methods: A structured and comprehensive search of databases was undertaken along with hand-searching of key journals and reference lists to locate relevant studies published and unpublished up to January 2011. Six randomised controlled trials met predetermined inclusion criteria. Brief high-impact exercises (<30min) were examined for their effect on bone mineral density (BMD) among premenopausal women. Trial quality was assessed using the Effective Public Health Practice Project quality assessment tool. Study outcomes for analysis, absolute change (g/cm2) or relative change (%) in BMD at femoral neck, trochanter and lumbar spine were compared by calculating standardised mean difference (SMD) using fixed and random-effects models. Results: Quality scores of included trials varied from medium to high on a scale of one to three. Brief bouts of exercise led to significant increases in femoral neck BMD (SMD=0.64, 95% CI=0.38, 0.90, overall effect Z-value=4.84, p=0.001); a modest increase in trochanteric BMD (SMD=0.36, 95% CI=0.10, 0.61, Z-value=2.08, p=0.04); and no increase in spinal BMD (SMD=0.04, 95% CI=-0.23, 0.31, Z-value=0.26, p=0.79). Conclusion: Based on the meta-analysis, brief high-impact exercise improves BMD at the hip but not at the lumbar spine. Effectiveness of this form of exercise as a lifestyle physical activity for prevention of osteoporosis should be explored further in larger populations.