Bilateral effect of unilateral electroacupuncture on muscle strength

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 similar to 20 degrees 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.