Effects of Neuromuscular Joint Facilitation on Electromechanical Reaction Times of the Teres Major

[Purpose] The aim of the study was to investigate the changes of electromechanical (EMG) reaction times (RT) of the human teres major after neuromuscular joint facilitation (NJF) treatment. [Subjects] The subjects were 17 healthy males who were divided into two groups: a NJF group and a control group. The NJF group consisted of 10 subjects, and the control group consisted of 7 subjects. [Methods] Participants in the NJF group received NJF treatment. The EMG-RT, the premotor time (PMT) and the motor time (MT) during shoulder internal rotation movement were measured before exercise, right after exercise, and at 10, 20 and 30 minutes after exercise. [Results] There were no significant differences among the results of the control group. For the NJF group, there were significant differences in EMG-RT and MT between pre- and post- exercise, and 10-20 minutes after exercise, and there were significant differences in PMT between pre- and post- intervention, and 10 minutes after the intervention. [Conclusion] NJF intervention shortens not only PMT but also MT, which implies that NJF is effective for both premotor and motor processes.