Cross-education Effects of Muscle Strength and Balance on Unilateral Isokinetic Exercise in Ankle

Abstract

Purpose: Unilateral strength training effects on contralateral sides have been demonstrated in previous studies for lower extremity exercise, upper extremity exercise, and unilateral surface electrical stimulation. This study was performed to investigate the effects of unilateral ankle training on muscle strength and the balance of contralateral lower extremity in healthy adults.Methods: Thirty healthy subjects were randomized equally to a training or a control group. Those in the training group received unilateral ankle isokinetic strengthening training of the dominant leg (right side) for 4 weeks. Contralateral single-limb balance, including Anterio-Posterior Stability Index (APSI), Medio-Lateral Stability Index (MLSI) and Overall Stability Index (OSI), was assessed before and after intervention.Results: Comparison of pre- and post-test data revealed significant improvements in ipsi- and contralateral ankle strengths, and significant improvement in contralateral single limb balance.Conclusion: These results have practical implications because they demonstrate that unilateral ankle isokinetic exercise improves ankle muscle strength and balance ability of contralateral lower extremity.