CHANGES IN MUSCLE THICKNESS, PENNATION ANGLE AND FASCILE LENGTH WITH AGING / 体力科学

ABSTRACT

The influences of age on muscle architectural characteristics, i. e., muscle thickness, pennation angle, fascicle length, were studied in 121 men and 229 women aged 17 to 85 yrs. The subjects were divided into three age groups (younger 17-39 yrs, middle-aged 40-59 yrs, elderly 60-85 yrs) for both genders. Muscle thickness and pennation angle of the vastus lateralis (VL), medial gastrocnemius (MG), and long head of triceps brachii (TB) muscles were measured using B-mode ultraso-nography, and fascicle length was estimated. In all age groups, men had significantly greater relative muscle thickness (to limb length) in VI, and TB than women, but not in MG. Relative muscle thickness of VL was significantly lower in elderly than in younger and middle-aged subjects. Ilowever, the corresponding differences in MG and TB were insignificant. The pennation angle of VL was significantly lower in elderly than in younger and middle-aged subjects, although there were no significant differences in pennation angles of MG and TB among the three groups. These results suggest that the decrease in thickness of vastus lateralis muscle with aging is significant, but not significant for medial gastrocnemius and triceps hrachii muscles.