The Measure of Success: Quantifying the Acute Effects of Whole Body Vibration on Hamstring Flexibility

Hamstring (HS) muscle strains are perhaps the most common muscle injuries in activities where sprinting is involved. An especially high rate of re-injury makes recovery a slow and frustrating process. Poor hamstring flexibility and strength imbalances are predisposing factors for hamstring muscle strains. Being flexible not only prevents injuries, but improves overall athletic performance. The purpose ofthis investigation was two-fold: To determine the acute effects of whole body vibration (WBV) on hamstring flexibility using the Active Knee Extension (AKE) Test as a measure of HS flexibility or Knee Range of Motion (ROM), and to design an apparatus to improve the accuracy of AKE measurement which would serve as a user-efficient device. Thirty female recreationally active athletes were randomly divided into 3 groups (n=lO WBV +stretch (WBV-S), n=lO WBV only (WBV), n=lO control (C). One-way Analysis of Variance (ANOV A) demonstrated notable increased in HS flexibility (9.83% WBV-S, 3.50%, WBV, and 1.56% C). Tukey Post-Hoc analysis indicated a sib’l1iiicant increase in HS flexibility for the WBV -S group which lasted 6 minutes. Based on the limitations from the AKE test employed in the study, design changes were made to the device to eliminate sources of error from body positioning and material flexibility to improve accuracy. The resulting device may have a profound influence on self-monitoring HS flexibility routines and test-retest accuracy.