title: Lower body site-specific sarcopenia and accelerometer-determined moderate and vigorous physical activity: the HIREGASAKI study.
abstract: OBJECTIVE
  It is unknown if the site-specific muscle loss of ageing muscle is associated with accelerometer-determined daily step count and/or intensity of physical activity. The purpose of this study was to examine the relationships between accelerometer- determined physical activity and lower body muscle size in women.
  
  
  METHODS
  Forty-eight women aged 52 to 76 years had their muscle thickness (MTH) measured by B-mode ultrasound at seven sites on the anterior and posterior aspects of their upper- and lower-leg. Daytime physical activity was measured using an accelerometer on 30 consecutive days and the total duration of each level of exercise intensity (light-PA, moderate-PA and vigorous-PA), average step count, and physical activity-related energy expenditure were calculated.
  
  
  RESULTS
  Age was inversely correlated with anterior 30% upper-leg MTH (r=-0.296, p<0.05), but not with other measured MTH sites. Light-PA was not significantly (p>0.05) correlated with measured lower body MTH. However, moderate-PA was correlated (p<0.05) with lower-leg MTH, while vigorous-PA was correlated (p<0.05) with lower-leg and anterior 30% upper- leg MTH. Following adjustment for confounding factors, the anterior and posterior lower-leg MTH was positively correlated (p<0.05) with duration of moderate- PA and vigorous-PA, as well as average step count.
  
  
  CONCLUSIONS
  Thus daily moderate and vigorous physical activity was associated with higher muscle mass in the lower leg, but not in the upper-leg muscle, suggesting that the site-specific upper-leg muscle loss may not be prevented or attenuated by daily physical activity.
authors.affiliation: Department of Health, Exercise Sciences, & Recreation Management, University of Mississippi, 215 Turner Center, Oxford, MS 38677, USA. t12abe@gmail.com
authors.forename: Takashi
authors.initials: T
authors.lastname: Abe
authors.forename: Naotoshi
authors.initials: N
authors.lastname: Mitsukawa
authors.forename: Robert S
authors.initials: RS
authors.lastname: Thiebaud
authors.forename: Jeremy P
authors.initials: JP
authors.lastname: Loenneke
authors.forename: Mark
authors.initials: M
authors.lastname: Loftin
authors.forename: Madoka
authors.initials: M
authors.lastname: Ogawa
mesh_terms: D061725:Accelerometry; D000368:Aged; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D001823:Body Composition; D005260:Female; D006801:Humans; D007866:Leg; D008875:Middle Aged; D009043:Motor Activity; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000473:pathology; D055948:Sarcopenia / Q000209:etiology* / Q000473:pathology / Q000517:prevention & control; D014463:Ultrasonography