The effects of acupuncture needle stimulation on skeletal muscle activity and exercise performance were studied in 17 healthy men. Each subject underwent maximal strength and muscular endurance force-generation tests of the nondominant hand and leg with EMG activity simultaneously recorded using a hand dynamometer and the Cybex II dynamometer. After a pretest evaluation of exercise performance and EMG activity, an acupuncture needle was inserted in the semitendinosus m. and either the flexor digitorum superficialis m. or flexor digitorum profundus m.; posttest evaluation was conducted following needle insertion. Results indicated no significant difference in exercise performance. However, there was a significant difference in EMG responses during maximum knee flexion on stimulated muscle and during endurance knee flexion on nonstimulated muscle (p = 0.044 and 0.05, respectively, in repeated measures ANOVA). No significant difference was noted in EMG for maximal hand grip. It may be concluded that single acupuncture stimulation affects neuromuscular function.