Acute Effects of Whole-Body Vibration on Lower Extremity Muscle Performance in Persons With Multiple Sclerosis

Background and Purpose: Whole-body vibration (WBV) is a relatively new form of exercise training that may influence muscle performance. This study investigated the acute effects of high (26 Hz) and low (2 Hz) frequency WBV on isometric muscle torque of the quadriceps and hamstrings in persons with multiple sclerosis (MS). Participants and Method: Fifteen individuals (mean age = 54.6 years, SD = 9.6) with MS and Expanded Disability Status Scale (EDSS) scores ranging from 0-6.5 (mean = 4.2, SD = 2.3) participated in this randomized cross-over study. Following baseline measures of isometric quadricep and hamstring torque, subjects were exposed to 30 seconds of WBV at either 2 or 26 Hz. Torque values were measured again at 1, 10 and 20 minutes post vibration. Subjects returned one week later to repeat the same protocol at the alternate vibration frequency. Results: There were no significant differences in isometric torque production between the 2 and 26Hz WBV conditions. There was also no significant difference between baseline torque values and those measured at 1, 10 and 20 minutes following either vibration exposure. However, there was a consistent trend of higher torque values following the 26 Hz WBV when compared to the 2 Hz condition for both quadriceps and hamstrings. Discussion and Conclusion: Although not statistically significant, peak torque values for both quadriceps and hamstrings were consistently higher following 30 seconds of WBV at 26 vs. 2 Hz. Whether or not WBV presents a viable treatment option as either a warm-up activity or a long-term exercise intervention is yet to be determined. Future studies should include a wider variety of WBV parameters and the use of functional outcome measures