High-frequency vibration training increases muscle power in postmenopausal women

Objective: To test whether training on a high-frequency (28Hz) vibrating platform improves muscle power and bone characteristics in postmenopausal women. Design: Randomized controlled trial with 6-month follow-up. Setting: Outpatient clinic in a general hospital in Italy. Participants: Twenty-nine postmenopausal women (intervention group, n = 14; matched controls, n = 15). Intervention: Participants stood on a ground-based oscillating platform for three 2-minute sessions for a total of 6 minutes per training session, twice weekly for 6 months. The controls did not receive any training. Both groups were evaluated at baseline and after 6 months. Main Outcome Measure: Muscle power, calculated from ground reaction forces produced by landing after jumping as high as possible on a forceplate, cortical bone density, and biomarkers of bone turnover. Results: Over 6 months, muscle power improved by about 5% in women who received the intervention, and it remained unchanged in controls (P=.004). Muscle force remained stable in both the intervention and control groups. No significant changes were observed in bone characteristics. Conclusion: Reflex muscular contractions induced by vibration training improve muscle power in postmenopausal women.