Level of agreement between physical activity levels measured by ActiHeart and the International Physical Activity Questionnaire in persons with intellectual disability

Purpose: The purpose of this study was to determine the level of agreement between objective physical activity (PA) (ActiHeart (R)) and subjective proxy-respondent International Physical Activity Questionnaire-short version (IPAQ-S) data in adults with intellectual disabilities (IDs). Method: Fifty-eight participants wore ActiHeart (R) monitors for seven consecutive days. Caregivers of each participant completed the IPAQ-S on behalf of the participant. Total PA, time spent in light, moderate, and vigorous activity as well as time spent being sedentary were assessed by the IPAQ-S and the ActiHeart (R). Results were compared by means of correlation analyses. The level of agreement was presented with Bland-Altman plots. Results: Objective PA (ActiHeart (R)) was higher (225.57 +/- 91.96 min/week) than IPAQ-S PA reported by care-givers (177.06 +/- 309.17 min/week). Weak significant correlations were observed between the ActiHeart (R) and IPAQ-S instruments for sedentary behavior (r = 0.31; p = 0.04); no significant correlations for light (r = -0.04; p = 0.8), moderate (r = -0.07; p = 0.63), or vigorous PA (r = -0.2; p = 0.18) were found. Limited agreement between objectively determine PA (ActiHeart (R)) and IPAQ-S was found. Conclusion: IPAQ-S is inaccurate when determining PA in persons with ID as it significantly underestimates the true levels of PA in this cohort.