Abstract
CATEGORY: Basic Sciences/Biologics; Other INTRODUCTION/PURPOSE: Foot drop is a debilitating condition which may be caused by peripheral nerve pathology. Focused vibration therapy (FVT) is a novel treatment in this setting which aims to improve the response of muscle motor units to nervous stimuli, improving muscle function and rehabilitation potential. This study investigates the effect of FVT on tibialis anterior (TA) function in normal subjects to determine the optimal timing of application. METHODS: Fifteen normal subjects with mean age 25.47±3.27 years and BMI of 21.93±1.54kg/m(2) were recruited. Using surface electromyography (EMG), a rotary potentiometer, video analysis (KINOVEA software), and force gauges, the activity of TA, ankle range of movement (ROM), and force at maximal isometric voluntary contraction (MVC) in dorsiflexion were measured. Baseline TA strength was recorded, and participants then performed a series of dorsiflexion exercises to induce fatigue. Strength measurements were repeated after a 5-minute rest period (control). This process was repeated with FVT applied before exercise (FVBE) and after exercise (during the rest period, FVAE). FVT was delivered over the TA muscle belly at 75Hz / 0.4mm amplitude. Data was analysed using ANOVA. RESULTS: There was no significant change in EMG readings or dorsiflexion ROM between baseline, control and FVBE/FVAE measurements. Compared to baseline, MVC increased by 10.87N (6.6%) after FVBE (p=0.034) and 13.87N (8.4%) after FVAE (p=0.034). Compared to control, MVC did not increase significantly with FVBE, but did increase by 7.70N (4.3%) following FVAE (p=0.049). CONCLUSION: FVT improved the MVC of TA - this was most pronounced when FVT was applied during the recovery phase, after exercise. The lack of EMG / ROM improvement is expected in normal subjects. Our results suggest that FVT is more effective than passive rest and may enhance muscle strength recovery. Further work will investigate the optimal dose of FVT and response in patients with pathology.