title: Tracking of Pedometer-Determined Physical Activity in Healthy Elderly Japanese People.
abstract: BACKGROUND
  Tracking refers to the tendency for an individual to maintain their rank within a group over time. This study longitudinally investigated the 8-year tracking of pedometer-determined physical activity among physically independent elderly Japanese people aged 72 to 80 years.
  
  
  METHODS
  Steps/day were measured when participants were aged 72 and assessed again after 2, 5, and 8 years. The number of participants with a 2-year follow-up (72 to 74 years) was 177 (101 males, 76 females), with a 5-year follow-up (72 to 77 years) was 183 people (110 males, 73 females), and with an 8-year follow-up (72 to 80 years) was 145 people (91 males, 54 females). Step counts were continuously measured for 1 week in January, April, July, and October during each year of assessment.
  
  
  RESULTS
  A high rank correlation coefficient for steps/day exceeding 0.60 was obtained at the 2-, 5- and 8-year follow-up examinations for both males and females.
  
  
  CONCLUSIONS
  This study suggests that the rank within a group of pedometer-determined steps/day remains stable over up to 8 years in healthy Japanese people aged between 72 to 80 years old.
authors.affiliation: Ehime University, Matsuyama, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Mieko
authors.initials: M
authors.lastname: Shimada
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakagawa
authors.forename: Susumu S
authors.initials: SS
authors.lastname: Sawada
authors.forename: Mamoru
authors.initials: M
authors.lastname: Nishimuta
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Kimura
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ohashi
authors.forename: Hidenori
authors.initials: H
authors.lastname: Asai
authors.forename: Hideo
authors.initials: H
authors.lastname: Miyazaki
authors.forename: I-Min
authors.initials: IM
authors.lastname: Lee
authors.forename: Steven N
authors.initials: SN
authors.lastname: Blair
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshitake
mesh_terms: D056044:Actigraphy / Q000379:methods*; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007564:Japan; D008137:Longitudinal Studies; D008297:Male; D016138:Walking / Q000502:physiology*