A prophylactic effect of local vibration on quadriceps muscle fatigue in non-athletic males: a randomized controlled trial study.
Khadijeh Otadi, Mehri Ghasemi, Shohreh Jalaie and 5 others
PMID 30936635WHAT IT FOUND
Local vibration applied to the quadriceps before fatigue testing allowed young men to sustain maximal contraction longer than sham vibration.
However, it did not significantly change muscle electrical activity or median frequency. The effect was small, so do not expect this to prevent fatigue in clinical populations.
Key findings
01Time to reach fatigue was significantly longer in the local vibration group compared to the sham group.
02There were no significant differences between groups in muscle electrical activity (RMS) or median frequency (MF).
03The study had low statistical power (0.12) and a small effect size (0.35) for the difference in maximal voluntary contraction changes.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only healthy young males, so results cannot be generalized to older adults, females, or patients with neuromuscular or cardiovascular conditions. The statistical power was very low (0.12), meaning the study was likely underpowered to detect small but clinically relevant differences. The effect size for the difference in MVC changes was small (0.35). The study did not report blinding of participants to the sham condition beyond the device being turned off, which may introduce bias.
Declared interests
The study was supported by Tehran University of Medical Sciences, and the authors declared no conflicts of interest.
The easy way to misread this
Do not interpret the significant increase in MVC within the vibration group as evidence of superiority over sham. The between-group difference in MVC changes had a small effect size and low statistical power, and the primary measure of muscle fatigue resistance (time to fatigue) was the only robust finding.