Effect of electromyographic feedback and static stretching on artificially induced muscle soreness

Thirty-six male subjects aged 18 to 26 years were assigned at random to one of three treatment groups: biofeedback, static stretch, and control. Muscle soreness was produced in all subjects by an 80% maximal eccentric contraction of the biceps brachii. The subjects in the biofeedback group applied auditory electromyographic (EMG) feedback at 6, 25, 30, 49, and 54 hours after the exercise, and the stretch group applied static stretch to the exercised arm at the same time periods. Observations of EMG activity and perceived pain level were made immediately before and after exercise, and at 24, 48, and 72 hours following exercise. When compared with a control group, both auditory biofeedback and static stretching significantly reduced EMG muscle activity but had no significant effect on perceived pain. The EMG activity and perceived pain of the subjects in each treatment group significantly differed across observations.