Validation of a novel, objective measure of occupational sitting.
OBJECTIVE
To test the validity of a sitting pad (SP) to measure desk based sitting time and transitions, against camera derived direct observation; and to compare the data with those from inclinometers in the ActivPAL(3) (AP) and ActiGraph GT3X+ (AG).


METHODS
Australian employees (n=13; 9 women; mean age 30 ± 6.5 years) were provided with a SP, AG and AP in 2011. A camera recorded chair based transitions during a prescribed and a free living protocol. Mean sitting time and transitions were calculated for each device and intra-class correlations (ICCs) and mean differences between (a) the SP and the camera and (b) the AP, AG and camera, were compared.


RESULTS
During the prescribed protocol, the smallest mean differences compared with the camera were for the SP; sitting time 0.30 ± 0.21 minutes, transitions -0.46 ± 0.78. During free living, both the SP and AP (set to record events greater than 3 seconds) showed excellent levels of agreement with the camera for sitting time (0.999 and 0.990 respectively) and transitions (0.997 and 0.928 respectively). Agreement between the camera and the AG was poor for both sitting time and transitions (0.257 and 0.033 respectively).


CONCLUSIONS
The SP is a highly accurate measure of desk based sitting time and transitions and provides novel measurement and intervention opportunities for research into occupational sitting.
St Lucia Campus, School of Human Movement Studies, The University of Queensland, Australia. g.ryde@uq.edu.au
Gemma C
GC
Ryde
Nicholas D
ND
Gilson
Alessandro
A
Suppini
Wendy J
WJ
Brown
D000288:Administrative Personnel; D000328:Adult; D056228:Feedback, Sensory; D005260:Female; D006801:Humans; D007374:Interior Design and Furnishings; D008297:Male; D016273:Occupational Exposure / Q000032:analysis*; D011187:Posture; D011793:Queensland; D015203:Reproducibility of Results; D057185:Sedentary Behavior; D013997:Time Factors; D014741:Video Recording; D017132:Workplace; D055815:Young Adult