Activity of Swallowing-related Muscles during Open-mouth Resistance Training in the Supine Position

Abstract

　It has been reported that the swallowing function of older people declines with age. In cases when aspiration pneumonia occurs, fasting and bed rest can lead to sarcopenia, which in turn can result in more severe swallowing disorders. The causes of sarcopenia such as age, activity, nutrition, or disease may be inter-related, and in all cases, both nutritional intervention and exercise intervention are necessary. Therefore, with the goal of preventing the decline in swallowing function, we considered strength training exercises for the swallowing muscles that can be performed even during bed rest. The subjects were 17 healthy adults（10 males and 7 females）with a mean age of 31.9±6.2 years.

　Muscle activities of the supraspinatus, infraspinatus, and sternocleidomastoid muscles were recorded with a surface electromyograph during open mouth resistance training in the sitting and supine positions. The maximum and average amplitude values of the opening resistance exercise were calculated, and the differences in the maximum and average amplitude values for each muscle（group）and posture condition were compared. In the supraspinatus muscle group, the maximum amplitude value was higher in the sitting position than in the supine position, but the mean amplitude value was higher in the supine position than in the sitting position. In the sternocleidomastoid muscle, both maximum and mean amplitude values were higher in the sitting position than in the supine position. Exercise in the supine position, which is a non-antigravity position, showed the same muscle activity of the supraspinatus muscle group compared to the sitting position, but the sternocleidomastoid muscle activity was reduced, suggesting that the supraspinatus muscle group may be strengthened in patients with decreased task completion rate due to weak swallawing and sarcopenia, or during bed rest in the acute phase.