Related Experiment Video
Updated: May 29, 2026
Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
Effects of local muscle vibration on plantarflexor strength and activation in individuals with chronic ankle
Raed Alamri1,2,3, Joshua Mohess4, Troy Blackburn4
1MOTION Science Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA - Raalamri@unc.edu.
Background:
Chronic ankle instability (CAI) is associated with neuromuscular impairments that increase reinjury risk. Although vibration can enhance neuromuscular function, the effects of local muscle vibration (LMV) in individuals with CAI are unknown. This study examined the immediate effects of LMV on plantarflexor strength and activation and whether stance position influences these responses.
Methods:
Twenty individuals with CAI (age, 21±2 years; 3±1 lifetime ankle sprains) participated. All participants met the inclusion criteria for CAI established by the International Ankle Consortium. Participants completed two separate sessions, each involving Pre Control, Post Control/Pre LMV, and Post LMV assessments. Maximal voluntary isometric contraction of the plantarflexor muscles during each assessment was used to calculate peak torque (PT), rate of torque development (RTD), and EMG amplitude. LMV was applied to the plantarflexor muscles in 1 of 2 randomized stance positions: 1) a mini-squat, or 2) a mini-squat with heels raised. LMV (2 g acceleration, 30 Hz frequency) was delivered in 6 sets of 60 seconds each, with 2 minutes of rest between sets. Paired t-tests evaluated pre-to-post changes in primary (PT and RTD) and secondary outcomes (EMG amplitude) following the control and LMV conditions. A two-way ANOVA compared changes between stance conditions.
Results:
LMV improved PT (P=0.035) and RTD (P=0.029) compared to the control condition. No significant changes were found for EMG amplitude or between stance conditions (P>0.05).
Conclusions:
LMV acutely improves PT and enhances RTD across both stances, suggesting its potential as a targeted neuromuscular intervention for individuals with CAI.
