Tuesday, December 6, 2011

Effect of whole-body vibration on subsequent sprint performance

Whole-body vibration (WBV) intervention is a common practice in training and before game in some clubs as a means to improve anaerobic performance. What is the evidence behind WBV use? Does this intervention improve performance?

Whole-body vibration before sprinting
In a recent study, Ronnestad and Ellefsen (2011) had their soccer players perform either 30sec half-squat with WBV at 30 Hz or half squat without WBV 1min before a 40-m run. Their results showed that performance was significantly improved by almost 1% after WBV. Interestingly, no change in performance was observed when WBV frequency was 50Hz.

What this study shows?
1.    Sprint performance might improve when combining half squat with WBV for 30sec.
2.    Optimal frequency for this intervention seems to be 30Hz.

Unanswered question
  • How long does this beneficial effect of WBV last? Ronnestad and Ellefsen (2011) had their soccer players sprint 1 min after the intervention so we do not know what would happen if the sprint was performed after 5, 10 or 20 min which is a more realistic scenario in football.

What is the ideal combination of WBV frequency and duration?
This was the research question set by Da Silva-Grigoletto and colleagues (2011) in a group of health but non well-trained volunteers. In their study, individuals performed half squat with WBV frequency at 30 Hz. Duration varied from 30 to 90 sec. Also number of sets was 3, 6 or 9. WBV with half squat were performed before countermovement and squat jump and power output test at half squat.

Main findings
  1. WBV for 60 sec produced the best results.
  2. Number of sets affected subsequent performance. Performing six 60-sec sets of WBV resulted in greater improvement in power output in subsequent testing.
It is important to keep in mind that these results were in non well-trained athletes. Thus, we do not know if they directly apply to well-trained football players. 

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