Definitions of sedentary in physical-activity-intervention trials: a summary of the literature.

This review describes the definitions of sedentary used to screen community-dwelling adults in physical-activity-intervention trials published from 2000 to 2005. Results of 42 trials showed that definitions of sedentary varied from <20 to <150 min/week of physical activity, and few reported the type (work, household, or leisure) or intensity of activity that was used to screen participants. The range of "sedentary" samples makes it difficult to compare trial results or generalize findings. Published reports of exercise trials would be more useful to practitioners and researchers if they included an explicit description of the cut point used to define sedentary adults in the sample, in terms of maximum minutes or days per week of activity and the wording of the screening measure in terms of type and intensity of activity.