The Change of the Electromyogram and the Heart Rate during the Dynamic Muscle Work by Wearing the Pressure Suit

Abstract

The purpose of this study is to investigate the change of the electromyogram (EMG) and the heart rate (HR) during the dynamic work on the different pressure or pressure area by wearing the pressure suit which can apply pressure to the human body surface by the region individually. The EMG of the m, flexor carpi ulnaris and the m. biceps brachii during the upper extremities work (UEW) and the m. vastus lateralis during the lower extremities work (LEW) were measured. The subjects flexed their arms (UEW) or legs (LEW) at the elbow or knee joints angle 90-180 degrees with the load of 8%MVC of the m. biceps brachii or m. vastus lateralis respectively. The pressure applied was 10mmHg in the both works and 30mmHg (UEW) or 40mmHg (LEW). The pressure time before the work was 3min. or 40min.. In the UEW, upper extremities, upper+lower extremities, or whole body was pressured. In the LEW, lower extremities, lower+upper extremities, or whole body was pressured. The EMG of the working muscle in the both works was increased when the pressure applied to the region containing the working muscle or to the upper and lower extremities in the same time. The pressure was applied to the whole body, however, the increase of the EMG was not significant compared with that of the control value (non-pressure). The EMG of the m, biceps brachii during the UEW was large compared with that of the m. vastus lateralis. during the LEW against the same pressure. The HR was only increased when the pressure applied to the region containing the working muscle. The results suggest that 1) the effects of the pressure on the dynamic work is weak when the whole body is pressured by the present pressure suit, 2) attention should be given to the load of muscles in the upper extremity when the pressure suit is inflated, 3) the effects of the pressure on the HR is weak in the range of this work intensity.