Improvement of stance control and muscle performance induced by focal muscle vibration in youn- elderly women: A randomized controlled trial

OBJECTIVE: To determine the effect of a particular protocol of mechanical vibration, applied focally and repeatedly (repeated muscle vibration [rMV]) on the quadriceps muscles, on stance and lower-extremity muscle power of young-elderly women. DESIGN: Double-blind randomized controlled trial; 3-month follow-up after intervention. SETTING: Human Physiology Laboratories, University of Perugia, Italy. PARTICIPANTS: Sedentary women volunteers (N=60), randomized in 3 groups (mean age +/- SD, 65.3+/-4.2y; range, 60-72). INTERVENTION: rMV (100Hz, 300-500microm, in three 10-minute sessions a day for 3 consecutive days) was applied to voluntary contracted quadriceps (vibrated and contracted group) and relaxed quadriceps (vibrated and relaxed group). A third group received placebo stimulation (nonvibrated group). MAIN OUTCOME MEASURES: Area of sway of the center of pressure, vertical jump height, and leg power. RESULTS: Twenty-four hours after the end of the complete series of applications, the area of sway of the center of pressure decreased significantly by approximately 20%, vertical jump increased by approximately 55%, and leg power increased by approximately 35%. These effects were maintained for at least 90 days after treatment. CONCLUSIONS: rMV is a short-lasting and noninvasive protocol that can significantly and persistently improve muscle performance in sedentary young-elderly women.