Measuring Total Sitting Time in Working Adults

Introduction Much of the research about sitting measurement has focused on total sitting time [1] (Rosenberg et al) and leisure-time sedentary behaviours [2] (Clark et al 2009), with less attention given to other domains in which sitting and sedentary behaviours occur. This study aimed to assess the measurement properties of a measure of total and domain-specific sitting based on work and non-workdays for use in working adults.

Methods A convenience sample (N=95, 63% female) was recruited from two workplaces and by word-of-mouth in Sydney, Australia. Participants completed a study questionnaire on two occasions, seven days apart, and reported their domain-specific sitting time [i.e., a) while travelling to and from places; b) while at work; c) while watching TV; d) while using a computer at home; and e) while doing other leisure activities] on work and non-workdays. Participants also wore an Actigraph accelerometer for the seven days in between the test and retest, recording the times they wore the accelerometer, the days they worked, and their work times in a logbook. Analyses determined test-retest reliability with intraclass correlation coefficients (ICC) and assessed criterion validity against accelerometers using Spearman’s rho. Concurrent validity was assessed against the International Physical Activity Questionnaire (IPAQ) sitting measure.

Results Measuring total sitting based on a workday, non-workday and on average had fair to excellent test-retest reliability (ICC=0.46-0.90) and had sufficient criterion validity against accelerometry in women (r=0.22-0.46) and men (r=0.18-0.29). Measuring average total sitting time correlated well with average total sitting time assessed by IPAQ, indicating adequate concurrent validity in women (r=0.53) and men (0.69). Measuring domain-specific sitting at work on a workday was also reliable (ICC=0.63) and valid (r=0.45).

Discussion and Conclusion Measuring total sitting by specific domains provides a detailed assessment of sitting in working adults. Many working adults spend large amounts of time sitting each day. Therefore, we recommend that this measure of total sitting time based on specific domains on work and non-workdays be used in research investigating the relationships between sitting time and health in working populations.

References [1] Rosenberg DE, Bull FC, Marshall AL, Sallis JF, Bauman AE. Assessment of sedentary behavior with the International Physical Activity Questionnaire. J Phys Act Health. 2008;5(Supp 1):S30-S44.

[2] Clark BK, Sugiyama T, Healy GN, Salmon J, Dunstan DW, Owen N. Validity and reliability of measures of television viewing time and other non-occupational sedentary behaviour of adults: a review. Obes Rev. 2009 Jan;10(1):7-16.