Bilateral Effect of Unilateral Electroacupuncture on Muscle Strength

Abstract

Objectives:

This study aimed to examine the bilateral effect of 4 weeks of unilateral electroacupuncture on leg muscle strength.

Design:

The effect of unilateral electroacupuncture at two selected acupoints, Zusanli (ST-36) and Xiajuxu (ST-39), which are located on the anterior tibialis muscle, on dorsiflexion strength was evaluated by statistical analyses of the interactions between the muscle strength pre and post 4 weeks of intervention, between the two legs, and between an experimental and a control group.

Settings/location:

The trial was carried out in the exercise rehabilitation laboratory at Tianjin University of Sport.

Subjects:

Thirty (30) healthy men with an average age of 20.9 ± 2.98 (SD) years were randomly allocated into an electroacupuncture group (EG) and a control group (CG). They were physically active, but without specific strength training or previous experience of acupuncture.

Interventions:

Participants in the EG were given 3 sessions of electroacupuncture per week. In each session, the electroacupuncture was applied to the right leg at the acupoints with 8 duty cycles of 1 minute on and 1 minute off, pulse width of 1 millisecond, frequency of 40 Hz, and intensity of 30–40 V. Participants in the CG group kept their normal daily activities without additional intervention.

Outcome measures:

The maximum strength in dorsiflexion of each leg was examined by having participants lift weights in the range of motion of ∼20° at the ankle joint.

Results:

Repeated-measures analysis of variance with Bonferroni adjustment detected significant increase in strength of both legs (right 21.3%, left 15.2%) in the EG (p < 0.05) and the increase was significantly higher than that of the CG (p < 0.05). The CG showed no significant change (right 3.0%, left 4.8%), post-treatment.

Conclusions:

Unilateral electroacupuncture at the selected acupoints improved muscle strength of both limbs. These findings may have implications in physical therapy and rehabilitation settings.