Therapeutics
Chen-Li Chang, BS
PhD Student
Physical Therapist
Tainan, Tainan, Taiwan (Republic of China)
Yi-Fen Shih, PhD
Professor
Department of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University
Taipei, Taipei, Taiwan (Republic of China)
Lateral ankle sprains are common musculoskeletal injuries, with around 40% of cases progressing to chronic ankle instability (CAI). While traditional rehabilitation emphasizes muscle function and proprioception, emerging evidence suggests that sensory-based interventions may benefit CAI, although the mechanisms remain unclear. This study explores the impact of peripheral sensory-level electrical stimulation (ES) on sensorimotor function and performance in individuals with CAI. We hypothesize that ES enhances muscle activation and functional ability compared to sham stimulation.
Design:
ES was delivered to the tibial nerve near the popliteal fossa using biphasic current (100 Hz, 0.1 ms phase duration) at the highest tolerable sensory level without visible muscle contraction. The ES group received 40 minutes of stimulation; the sham group received only brief stimulation at the beginning and end. Pre- and post-intervention tests were conducted on the same day, with the post-tests performed immediately after the intervention. Outcome measures included the Y-balance test for anterior, posterior-lateral, and posterior-medial directions, along with surface EMG recordings from the tibialis anterior, peroneus longus, and soleus during the Y-balance test to assess functional ability and muscle activation.
Results:
Twelve participants with CAI were recruited. Preliminary results showed ES improved posterolateral Y-balance (106.78 ± 9.50 vs. 110.37 ± 8.18 cm, Z = 2.10, p = .036) and increased tibialis anterior activity in the anterior direction (31.75 ± 19.96% vs. 41.21 ± 24.07%, Z = 2.38, p = .017). Between-group analysis (Mann–Whitney U) indicated greater tibialis anterior activation in the posterolateral direction for ES (13.48 ± 18.62%) vs. sham (–15.31 ± 14.01%), U = 1.00, p = .011.
Conclusion:
These findings suggest sensory-level ES may enhance neural integration and functional outcomes in CAI, supporting its role as a promising adjunct to conventional rehabilitation. Further research with larger samples is warranted.
