Evaluation of methods to assess physical activity in free-living conditions

Med Sci Sports Exerc. 2001 Jul;33(7):1233-40. doi: 10.1097/00005768-200107000-00024.

Abstract

Purpose: The purpose of this study was to compare different methods of measuring physical activity (PA) in women by the doubly labeled water method (DLW).

Methods: Thirteen subjects participated in a 7-d protocol during which total daily energy expenditure (TDEE) was measured with DLW. Body composition, basal metabolic rate (BMR), and peak oxygen consumption were also measured. Physical activity-related energy expenditure (PAEE) was then calculated by subtracting measured BMR and the estimated thermic effect of food from TDEE. Simultaneously, over the 7 d, PA was assessed via a 7-d Physical Activity Recall questionnaire (PAR), and subjects wore secured at the waist, a Tritrac-R3D (Madison, WI), a Computer Science Application Inc. activity monitor (CSA; Shalimar, FL), and a Yamax Digi Walker-500 (Tokyo, Japan). Pearson-product moment correlations were calculated to determine the relationships among the different methods for estimating PAEE. Paired t-tests with appropriate adjustments were used to compare the different methods with DLW-PAEE.

Results: There was no significant difference between PAEE determined from PAR and DLW. The differences between the two methods ranged from -633 to 280 kcal.d(-1). Compared with DLW, PAEE determined from CSA, Tritrac, and Yamax was significantly underestimated by 59% (-495 kcal.d(-1)), 35% (-320 kcal.d(-1)) and 59% (-497 kcal.d(-1)), respectively. VO2peak explained 43% of the variation in DLW-PAEE.

Conclusion: Although the group average for PAR-PAEE agreed with DLW-PAEE, there were differences in the methods among the subjects. PAEE determined by Tritrac, CSA, and Yamax significantly underestimate free-living PAEE in women.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Activities of Daily Living*
  • Adult
  • Basal Metabolism
  • Body Composition
  • Body Mass Index
  • Energy Metabolism / physiology*
  • Ergometry / instrumentation
  • Ergometry / methods*
  • Female
  • Humans
  • Monitoring, Ambulatory / instrumentation
  • Monitoring, Ambulatory / methods*
  • Oxygen Consumption
  • Reference Values
  • Regression Analysis
  • Statistics as Topic