The Effects of Whole Body Vibration on the Limits of Stability in Adults With Subacute Ankle Injury

Abstract

Background Limited research exists on the effects of both high and low frequency whole body vibration (WBV) on individuals with subacute lateral ankle sprains. Hypothesis/Purpose To examine the difference in the effects of high and low frequency WBV on limits of stability (LOS) in adults with a subacute ankle sprain. It was hypothesized that WBV would improve effects on outcome variables for LOS as a component of dynamic balance. Study Design Quasi-experimental, pretest-posttest design. Methods Fifteen participants ages 19-27 years (Mean age 22±2.36) with either a Grade I or Grade II lateral ankle sprain received WBV in bilateral stance under three randomized conditions (high frequency-25 Hz, low frequency-6 Hz, and control, which consisted of bilateral stance with machine off) for six minutes over three sessions (one time per week). The LOS test, consisting of 5 variables, were assessed using the NeuroCom® Balance Manager-SMART EquiTest® (Natus Medical Incorporated, Pleasanton, CA) at baseline and after the intervention period. The participants completed a practice LOS test and then had a six-minute standing rest break. After the rest break, they completed the pre-LOS (baseline) test. Intervention was administered using the Galileo® Med L Chip Research (Novotec Medical GmbH, Pforzheim, Germany) for six minutes for the appropriate condition of either high or low frequency WBV or control. Data analysis was performed using 2-Way (2x3) Repeated Measures ANOVAs with additional post hoc testing as needed. Results Significant interactions were found for reaction time (RT), movement velocity (MVL), and maximal excursion (MXE) composite scores with a decrease in RT of 0.117 seconds (p=0.022) between control and high frequency conditions during the post LOS. For composite MVL, an increase of 0.547 degrees/second (p=0.002) between pre- and post-high frequency WBV occurred. For composite MXE, an increase of 2.13% p=0.031 (when comparing pre- and post-high frequency WBV. Conclusion Findings suggest that a single session of high frequency WBV in individuals with a subacute lateral ankle sprain may result in improvement in several components of postural stability. WBV is a quick intervention that could be implemented in physical therapy clinics, athletic training rooms, and workout facilities to improve an individual’s LOS as a component of dynamic balance one to eight weeks post lateral ankle sprain. Level of Evidence 2b