Effects of whole-body vibrations on neuromuscular fatigue: a study with sets of different durations

Background Whole body vibrations have been used as an exercise modality or as a tool to study neuromuscular integration. There is increasing evidence that longer WBV exposures (up to 10 minutes) induce an acute impairment in neuromuscular function. However, the magnitude and origin of WBV induced fatigue is poorly understood. Purpose The study aimed to investigate the magnitude and origin of neuromuscular fatigue induced by half-squat long-exposure whole-body vibration intervention (WBV) with sets of different duration and compare it to non-vibration (SHAM) conditions. Methods Ten young, recreationally trained adults participated in six fatiguing trials, each consisting of maintaining a squatting position for several sets of the duration of 30, 60 or 180 seconds. The static squatting was superimposed with vibrations (WBV 30 , WBV 60 , WBV 180 ) or without vibrations (SHAM 30 , SHAM 60 , SHAM 180 ) for a total exercise exposure of 9-minutes in each trial. Maximum voluntary contraction (MVC), level of voluntary activation (%VA), low- (T 20 ) and high-frequency (T 100 ) doublets, low-to-high-frequency fatigue ratio (T 20/100 ) and single twitch peak torque (TW PT ) were assessed before, immediately after, then 15 and 30 minutes after each fatiguing protocol. Result Inferential statistics using RM ANOVA and post hoc tests revealed statistically significant declines from baseline values in MVC, T 20 , T 100 , T 20/100 and TW PT in all trials, but not in %VA. No significant differences were found between WBV and SHAM conditions. Conclusion Our findings suggest that the origin of fatigue induced by WBV is not significantly different compared to control conditions without vibrations. The lack of significant differences in %VA and the significant decline in other assessed parameters suggest that fatiguing protocols used in this study induced peripheral fatigue of a similar magnitude in all trials.