The purpose of this study was to clarify the effect of cooling of proximal region of gastrocnemius muscle on electromyographic (EMG) activities during calf-raising exercise. Eight men and women performed calf-raising exercise every two seconds for twenty-five repetitions with or without cooling. Cooling was applied for the proximal region of the gastrocnemius. During the cooling, skin temperature was measured from the proximal and distal region of the lateral gastrocnemius muscle. Surface EMG activities were recorded from the proximal and distal lateral gastrocnemius (LGpro and LGdis, respectively), proximal and distal medial gastrocnemius (MGpro and MGdis, respectively) and soleus (Sol) muscles during the calf-raising exercise. Skin temperature of LGpro, i.e. cooling region, significantly decreased; however, no change was found in LGdis after 30 min cooling. In all tested regions, EMG activities in the cooling condition were significantly higher than those in the control condition. The relative EMG activity changes in cooling condition to the control condition were significantly higher in MGpro than MGdis; however, no significant difference were found between LGpro and LGdis. These results suggest that cooling of the proximal region of the gastrocnemius muscle induces significant changes in neuromuscular activities in cooled regions as well as noncooled region and that these changes would be strategy to avoid fatigue during required task.

DESCENTE SPORTS SCIENCE Vol.29/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE