HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 101/5/1328    most recent 00336.2006v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Macfarlane, D. J. Articles by Chan, D. Search for Related Content PubMed PubMed Citation Articles by Macfarlane, D. J. Articles by Chan, D.

Convergent validity of six methods to assess physical activity in daily life

Institute of Human Performance, The University of Hong Kong, Pokfulam, Hong Kong

Submitted 21 March 2006 ; accepted in final form 15 June 2006

The purpose was to examine the agreement (convergent validity) between six common measures of habitual physical activity to estimate durations of light, moderate, vigorous, and total activity in a range of free-living individuals. Over 7 consecutive days, 49 ethnic Chinese (30 men, 19 women), aged 15–55 yr, wore a Polar heart rate monitor, a uniaxial MTI, and triaxial Tritrac accelerometer, plus a Yamax pedometer for 600 min/day. They also completed a daily physical activity log and on day 8 a Chinese version of the 7-day International Physical Activity Questionnaire. At each level of activity, there was good agreement between the two questionnaire-derived instruments and the two accelerometry-derived instruments, but wide variation across different instruments, with two- to fourfold differences in mean durations often seen. The heart rate monitor overestimated light activity and underestimated moderate activity compared with all other measures. Spearman correlation coefficients were low to moderate (0.2–0.5) across most measures of activity, with the pedometer showing correlations with total activity that were often superior to the other movement sensors. We conclude that, with the use of commonly accepted cut points for defining light, moderate, vigorous, and total activity, little convergent validity across the instruments was evident, suggesting these measures are sampling different levels of habitual physical activity and care is needed when comparing their results. To provide a more stable comparison of activity among different people, across studies, or against accepted physical activity promotion guidelines, further work is needed to fine tune the different cut points across a range of common activity monitors to provide more consistent results during free-living conditions.

accelerometer; International Physical Activity Questionnaire; logbook; heart rate; pedometer

This article has been cited by other articles:

				K. Corder, U. Ekelund, R. M. Steele, N. J. Wareham, and S. Brage Assessment of physical activity in youth J Appl Physiol, September 1, 2008; 105(3): 977 - 987. [Abstract] [Full Text] [PDF]

				L. Klassen, C. Schachter, and R. Scudds An exploratory study of two measures of free-living physical activity for people with multiple sclerosis Clinical Rehabilitation, March 1, 2008; 22(3): 260 - 271. [Abstract] [PDF]