To investigate the effect of a single-session manual needle acupuncture procedure on peak isometric muscle torque and resistance to muscle fatigue.
Healthy participants (mean age 27.8 ± 9.8 years) were assigned to an acupuncture or control group. Each participant was required to perform a peak isometric muscle torque and 1-min isometric muscle fatigue task of the right knee extensors. Following 20-min of needle acupuncture (acupuncture group, N = 17) or 20-min rest (control group, N = 8), participants were required to repeat the peak isometric muscle torque and 1-min isometric muscle fatigue tasks. The acupoints included LV3, LI4, and GV20. ANOVA was performed for peak isometric muscle torque, muscle fatigue, muscle fatigue coefficient of variation (CV%), blood lactate, and heart rate.
There was a group by time interaction for the peak isometric torque (F = 5.9, P = 0.02, partial eta squared = 0.21). The control group revealed a 6.4% decline and the acupuncture group showed a 1.6% increase and in the repeat performance of the peak isometric muscle torque. No main effects were observed for isometric muscle fatigue, CV%, blood lactate, or heart rate.
Repeat performance of the peak isometric muscle torque was sustained following a 20-min acupuncture procedure compared to a decline in the control group following a 20-min rest procedure. Differences between groups might be associated with acute acupuncture procedure and acquired performance bias.