An objective method for measurement of sedentary behavior in 3-to 4-year olds

Objective: To test the ability of accelerometry to quantify sedentary behavior in 3- to 4-year-old children. Research Methods and Procedures: We developed a cutoff for accelerometry output (validation study) in 30 healthy 3 to 4 year olds, which provided highest sensitivity and specificity for the detection of sedentary behavior relative to a criterion method of measurement, direct observation using the children's physical activity form. We then cross-validated the cut-off in an independent sample of healthy 3 to 4 year olds (n = 52). Results: In the validation study, optimal sensitivity and specificity for the detection of sedentary behavior were obtained at an accelerometry output cut-off of <1100 counts/min. In the cross-validation, sensitivity was 83%: 438/528 inactive minutes were correctly classified. Specificity was 82%: 1251/1526 noninactive minutes were correctly classified using this cut-off. Discussion: Sedentary behavior can be quantified objectively in young children using accelerometry. This new technique could be considered for a wide variety of applications in the etiology, prevention, and treatment of childhood obesity.