title: Comparison of age-related, site-specific muscle loss between young and old active and inactive Japanese women.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors: Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan. t12abe@gmail.com
authors: Takashi
authors: T
authors: Abe
authors: Yasuo
authors: Y
authors: Kawakami
authors: Michael G
authors: MG
authors: Bemben
authors: Tetsuo
authors: T
authors: Fukunaga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D015438:Health Behavior; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D009043:Motor Activity; D018482:Muscle, Skeletal / Q000502:physiology*; D012959:Socioeconomic Factors