An international team of researchers investigated the effects of regular tai chi (TC) or jogging exercise on neuromuscular reaction in older people. Twenty-one long-term elderly TC practitioners were compared with 18 regular elderly joggers and 22 sedentary counterparts. Electromyography (EMG) was used to detect the neuromuscular reaction of the leg muscles to an unexpected ankle inversion perturbation. The latency of the muscles, which was defined as the time that the moment of perturbation began to the onset of the EMG response, was evaluated. There were significant differences in the latency of the rectus femoris (R) and anterior tibialis (T) muscles between the three groups, but there were no differences in the latency of the semitendinosus and gastrocnemius muscles. The R and T muscles in the TC and jogging groups were activated significantly faster than those in the control group. No significant difference was found for the muscle onset latencies between the TC and jogging groups.