Pocket Carried and Waist-Mounted Accelerometry

Abstract

Purpose: Evaluate differences in counts/min, physical activity intensity estimates, and perceived protocol compliance between wearing an accelerometer in the traditional waist attachment site versus worn in the thigh pocket. Methods: Ten participants wore 2 accelerometers concurrently while engaging in 3 treadmill-based laboratory test conditions, including a 4.8 km/h athletic short, 4.8 km/h blue jeans, and 9.6 km/h athletic shorts and one free-living test condition. Accelerometer 1 was attached in the traditional method (belt-worn at the waist) while accelerometer 2 was placed in the front thigh pocket. Questionnaire reported compliance beliefs pertaining to a 7-day wear time protocol were also obtained. Results: All participants self-reported that the pocket option would increase the convenience of study compliance. In laboratory testing, small mean differences were observed for condition 1, 2, and 3, respectively. Larger incongruity in central tendency was identified for vector magnitude and step counts for all laboratory based testing. High agreement was observed for all Bland-Altman analyses. Of practical importance, free-living assessment provided high agreement (≥ 90%) and correlation (r≥.758) between monitors at the two locations, with estimates of time spent in MVPA (r=.962). Conclusion: Results from free living evaluation are promising. Due to the mixed findings across the evaluated metrics for laboratory tests, future research is needed to determine the suitability of utilizing the pocket as a potential site for accelerometer monitoring.