title: Association between habitual light-intensity physical activity and lower-extremity performance: a cross-sectional study of community-dwelling older Japanese adults.
abstract: OBJECTIVE
  Habitual moderate vigorous-intensity physical activity (MVPA) positively affects lower-extremity performance. It is unclear whether habitual light-intensity physical activity (LPA), such as leisurely walking, has similar effects on lower-extremity performance. The aim of the present study was to identify the associations between habitual LPA and lower-extremity performance in older adults.
  
  
  METHODS
  This cross-sectional study included 802 community-dwelling Japanese older adults, 187 men and 615 women, aged 60-96 years. A uniaxial accelerometer measured physical activity intensity for over 10 h/day continuously for 7 days. Lower-extremity performance was assessed by repeated chair stands (RCS), single-leg stance (SLS) and Timed Up & Go (TUG). Multiple regression analysis was used to identify whether LPA was associated with lower-extremity performance, independent of potential confounders.
  
  
  RESULTS
  The multiple regression analysis showed that longer LPA was significantly associated with better performance of RCS and TUG. In the results of stratified analyses, LPA was significantly associated with RCS in participants aged ≥75 years and in those with at least one medical condition or joint pain. LPA was also associated with TUG in participants aged ≥75 years, in those with at least one medical condition or joint pain and in those with low MVPA (<13.9 min/day).
  
  
  CONCLUSIONS
  These results suggest that habitual LPA is a useful lifestyle indicator of better performance in lower-extremity strength and gait with dynamic balance. Maintaining a higher level of LPA could be a recommended approach for preserving lower-extremity performance, especially among physically frail older adults.
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan; The Japan Society for the Promotion of Science, Tokyo, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Osuka
authors.forename: Noriko
authors.initials: N
authors.lastname: Yabushita
authors.forename: Miji
authors.initials: M
authors.lastname: Kim
authors.forename: Satoshi
authors.initials: S
authors.lastname: Seino
authors.forename: Miyuki
authors.initials: M
authors.lastname: Nemoto
authors.forename: Songee
authors.initials: S
authors.lastname: Jung
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Okubo
authors.forename: Rafael
authors.initials: R
authors.lastname: Figueroa
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D015577:Geriatric Assessment / Q000379:methods*; D006184:Habits; D006801:Humans; D007564:Japan; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*
keywords: lower-extremity performance; objectively measured light-intensity physical activity; older adults