AGE AND SEX DIFFERENCES IN JAPANESE LIFE FITNESS / 体力科学

ABSTRACT

The purpose of the present study is to observe the effect of aging on life fitness in Japanese. Life fitness consists of such parameters as body composition, joint torque (JT), leg extension power (LP) and run power (RP) . Subjects were 719 males and 859 females, from 20 to 80yrs old. The “aged” groups (over 70 years) indicated a higher percentage of body fat, compared to the younger groups. The subcutaneous fat thickness at the arms and legs measured by ultrasonography, was independent of age, while that at the abdomen and back was higher among aged groups. It is therefore considered that the higher percentage body fat observed in the aged groups is due mainly to accumulated subcutaneous fat at the abdomen and back. Muscle volume (MV) at the upper extremity indicated no significant difference among age groups; while that at the lower extremity (especially knee extensor muscle) was significantly lower in the aged groups compared to the younger groups. The ratio of JT to MV, considered as the index of specific tension, was lower for the aged groups than younger groups. Mechanical power performed during ergometer running and leg extension power were significantly lower for the aged groups. It is concluded that aged peoples due to low muscle volume of the knee extensor, experience deterioration in leg extension power, resulting in lower mechanical power for runnine.