ABSTRACT

　The purpose of this study was to examine the 5-year longitudinal change in the quantity and quality of trunk skeletal muscle of the elderly. In this report, we indicated the results of changes within 1 year for 23 elder males and females (age: 71.7±4.3 years, body mass index: 22.1±2.6 kg/m²). Height, body weight, body fat and physical functions were measured. B-mode ultrasound transverse images from the rectus abdominal muscle at lower side of 2 to 3 cm beside the umbilicus and multifidus muscle at the intervertebral disc level of the fourth and fifth lumbar vertebra were acquired. As quantitative and qualitative indices, the muscle thickness and echo intensity of the two muscles are calculated. The subcutaneous fat thickness at the same position was also measured. As a result, the echo intensity corrected by the subcutaneous fat thickness tended to increase in the rectus abdominis muscle. Result of a stepwise multiple regression analysis with the absolute change in all measurement items as independent variables indicated the change of echo intensity in rectus abdominis muscle related only to the muscle thickness of the same muscle. Although there was no significant change in muscle thickness, these results might suggest that at least in the rectus abdominis muscle, loss of skeletal muscle with aging relates to fat infiltration within skeletal muscle.

DESCENTE SPORTS SCIENCE Vol.39/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE