Intra-individual variation and estimates of usual physical activity.

  title={Intra-individual variation and estimates of usual physical activity.},
  author={Sarah Levin and David R. Jacobs and Barbara E. Ainsworth and Mark T. Richardson and Arthur S. Leon},
  journal={Annals of epidemiology},
  volume={9 8},
PURPOSE The magnitude of intra-individual variation, as determined by three methods of physical activity (PA) assessment, was estimated to determine the optimal number of repeated measures needed to reliably measure an individual's usual PA habits. METHODS Data were obtained from 77 healthy adults enrolled in the Survey of Activity, Fitness, and Exercise (SAFE). PA was measured by: 1) Caltrac accelerometers worn 48-hours every 26 days for one year; 2) concurrent 48-hour PA records (PARs); and… CONTINUE READING