This study explored definitions of sedentary behavior and examined the relationship between sitting time and physical inactivity using the sitting items from the International Physical Activity Questionnaire (IPAQ).
Participants (N = 289, 44.6% male, mean age = 35.93) from 3 countries completed self-administered long- and short-IPAQ sitting items. Participants wore accelero-meters; were classified as inactive (no leisure-time activity), insufficiently active, or meeting recommendations; and were classified into tertiles of sitting behavior.
Reliability of sitting time was acceptable for men and women. Correlations between total sitting and accelerometer counts/min <100 were significant for both long (r = .33) and short (r = .34) forms. There was no agreement between tertiles of sitting and the inactivity category (kappa = .02, P = .68).
Sedentary behavior should be explicitly measured in population surveillance and research instead of being defined by lack of physical activity.
Rosenberg is with the Joint Doctoral Program in Clinical Psychology, San Diego State University and University of California, San Diego, CA 92103. Bull is with the School of Sport and Exercise Sciences, Loughborough University, Leicesteshire, LE11 3TU, U.K. Marshall is with the School of Public Health, Queensland Institute of Technology, Kelvin Grove, QLD 4059, Australia. Sallis is with the Psychology Dept, San Diego State University, San Diego, CA 92182. Bauman is with the School of Public Health, University of Sydney, NSW 2006, Australia.