title: Objectively-measured physical activity and body weight in Japanese pre-schoolers.
abstract: BACKGROUND
  The prevalence of thinness has increased among Japanese children.
  
  
  OBJECTIVE
  The purpose of this study was to examine the association between physical activity and body mass index (BMI) among Japanese pre-school children.
  
  
  METHODS
  Subjects were 425 4-6-year-old Japanese girls and boys. Their weights were classified as normal, overweight or thin, based on Cole's international cut-offs for BMI. Physical activity was assessed using a triaxial accelerometer (ActivTracer, GMS) for 6 consecutive days.
  
  
  RESULTS
  Physical activity in overweight children was comparable to that in normal-weight children after controlling for age and gender. However, thin children spent significantly greater time engaged in low-intensity activities (physical activity ratio < 2) and spent less time engaged in light-intensity physical activity (2 ≤ physical activity ratio < 3) and moderate-to-vigorous physical activity (physical activity ratio  ≥ 3) than normal-weight and overweight children, and less time engaged in higher-intensity physical activity (physical activity ratio ≥ 4) than normal-weight children. Moreover, thin children spent significantly less time engaged in locomotive physical activity than normal-weight or overweight children.
  
  
  CONCLUSIONS
  This study suggests that thinness, rather than excess weight, is associated with decreased light, moderate and high intensity physical activity in Japanese pre-school children.
authors.affiliation: Division of Integrated Sciences, J. F. Oberlin University, Machida , Tokyo , Japan and.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Tanaka
authors.forename: Shigeho
authors.initials: S
authors.lastname: Tanaka
mesh_terms: D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D009043:Motor Activity; D013851:Thinness / Q000453:epidemiology* / Q000209:etiology