MUSCLE WORK CAPACITY IN ELDERLY PEOPLE / 体力科学

ABSTRACT

This review describes age-related changes in muscle work capacity and muscle blood flow as an indicator of oxygen transport capacity. Maximal endurance time, measured using a given relative load, did not differ between younger and older people ; and the strength decline ratio, as a percent of maximal voluntary contraction, remained constant across the middle- and old age groups, or slightly increased with age. A likely explanation would be the agerelated modification of muscle fiber composition. In contrast, the recently proposed submaximal test indicated that the breaking point of blood pressure regulation (BP<SUB>critical</SUB>), during progressively increasing exercise, significantly decreased in the elderly in their 70 s. Concerning muscle blood flow in the elderly, the results are inconsistent. Some studies indicated the muscle blood flow during leg or handgrip exercise can be preserved in the elderly ; other studies reported it decreases in older people both at baseline and during exercise. Longitudinal studies on elderly people show that training can reverse age-related peripheral circulatory changes in healthy older people. In addition, daily physical activity is related to muscle work capacity and gradually decreases with age. Thus, further studies are needed concerning whether the decline of muscle work capacity or the reduction of muscle blood flow with age is due to aging or inactivity in older people.