PURPOSE: The purpose of this study was investigate the changes of gastrocnemius (GCM) muscle activity by applying different hot and cold therapeutic modalities.
METHODS: A total of 20 healthy subjects were enrolled into the study. We selected transfer modalities that are frequently used in clinical settings: conduction, radiation, and convection. We performed hot pack, ice pack, and infrared therapy for 10, 20, and 30 minutes. After each application, a break was taken between each day. In addition, we performed cryotherapy for 3 min (airflow rate = -6～-20℃). We measured muscle activity changes in the GCM muscle.
RESULTS: For the conduction method, muscle activity significantly increased after ice pack therapy for 10 min and 20 min but decreased after hot pack therapy for 10 min and 20 min. For the radiation method, muscle activity significantly decreased after infrared therapy for 10 min and 20 min. For the convection method, muscle activity significantly increased after cryotherapy for 3 min and 10 min. There were no differences in the change of muscle activity in the conduction and radiation transfer method using heat. However, there were differences in the change of muscle activity in the conduction and convection transfer method with cold application.
CONCLUSION: For a reduction in muscle activity, regardless of the transfer type, thermal application for 20 min would be effective. For an increase in muscle activity, cold pack application or cryotherapy for 20 min would be effective. This study could contribute toward therapeutic modality application in changing muscle activity.