To compare the effect of habitual recreational sports and exercise activity on age-related, site-specific muscle loss in young and old women in Japan.
Participants included 152 young (aged 20–35 years) and 157 old (aged 60–85 years) women who were classified into 4 subgroups on the basis of their habitual (more than once a week) sports and exercise activity: young active (n = 86), young inactive (n = 66), old active (n = 43), and old inactive (n [SUPERSCRIPT EQUALS SIGN] 114). Muscle thickness (MTH) and fat thickness (FTH) were measured by ultrasonography at 8 sites, with MTH expressed in terms relative to limb length (MTH/L) or height (MTH/Ht). Percent fat was estimated from FTH, and fat-free mass was calculated.
Fat-free mass was similar between younger and older women and between active and inactive women. MTH/L in the quadriceps (P < .001), abdomen (P < .001), and triceps surae (P < .05) was lower in the older women than in the younger women. In contrast, MTH/L in the hamstrings, subscapula, and biceps was higher (P < .01) in the older women than in the younger women. Compared with the MTH of the young inactive women, the MTH of the young active women was greater (P < .05) in 5 sites. Similarly, MTH/L in the quadriceps and triceps was higher (P < .05) in the old active women than in the old inactive women. However, quadriceps MTH/L and abdomen MTH/Ht were still lower (P < .001) in the old active women than in the young inactive women.
Age-related muscle loss remains site-specific in both active and inactive young and old women, even when habitual physical activity has an effect on muscle size.
1Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan.
2Department of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan.
3Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma.
4National Institute of Fitness and Sports in Kanoya, Kanoya, Kagoshima, Japan.
Address correspondence to: Takashi Abe, PhD, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277–8653, Japan (email@example.com).
The authors declare no conflict of interest.