Immediate effect of neuromuscular electrical stimulation on the abductor hallucis muscle: A randomized controlled trial

ABSTRACT

Hallux valgus (HV) is a foot deformity with deviation of the greater toe and the first metatarsal. There is little evidence on training the abductor hallucis muscle (AbdH) to treat HV because of the difficulty in implementing the necessary interventions. Although neuromuscular electrical stimulation (NMES) has been used to induce voluntary exercise, there is currently no study on NMES for AbdH. We aimed to verify the immediate effect of NMES on the AbdH muscle function. For the NMES group (n = 15), electrical stimulation was applied for 20 min. In the sham group (n = 15), the stimulating device was set but not turned on. Electromyogram, HV angle (HVA) at rest and during abduction of the big toe, and strength of the AbdH were evaluated. Analysis of covariance was used to investigate differences between groups using the baseline as the covariate. NMES significantly improved the maximal voluntary isometric contractions (%MVIC), HVA at exercise, and muscle strength (%MVIC: p = .00, HVA exercise: p = .00, AbdH strength: p = .00). HVA at rest showed no change (p = .12). Application of NMES on the AbdH muscle immediately improved its activity output, muscle strength, and HVA during exercise.

KEYWORDS:

• Neuromuscular electrical stimulation
• hallux valgus
• abductor hallucis muscle
• electromyogram

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Acknowledgments

The authors would like to thank the participants from Kyoto University for their help with the data collection. Furthermore, we would like to thank Editage™ (www.editage.jp) for the English language editing.

Declarations of interest statement

One co-author, Sachiko Abiko, is an employee of ITO CO., LTD, which is the manufacturer of the NMES device used. She did not participate in any data collection or data analysis. The other authors have no conflicts of interest to declare.