Effect of regular Tai Chi and jogging exercise on neuromuscular reaction in older people

Objectives: to investigate the effects of regular Tai Chi (TC) or jogging exercise on neuromuscular reaction in older people. Design: cross-sectional study. Setting: university biomechanics laboratory. Subjects: 21 long-term elderly TC practitioners were compared with 18 regular elderly joggers and 22 sedentary counterparts. Measurements: 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. Results: a one-way ANOVA revealed that there were significant differences in the latency of the rectus femoris (R) and anterior tibialis (T) muscles between the three groups, but that there were no differences in the latency of the semitendinosus (S) and gastrocnemius (G) muscles. Further tests indicated that 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. Conclusion: maintaining information processing speed during ageing is important, because of the role that it plays in many everyday events. The R and T muscles in the regular TC and jogging groups showed faster responses to unexpected ankle inversion perturbations, which is helpful for the timely correction of postural disturbances, than those in the sedentary control group.