Vol 15, Issue 7

Measurement of Physical Activity with Wrist-Worn ActiGraph GT3X+ in Older Women

Authors

Michal T. SmithUniversity of South Carolina
Erin E. KishmanUniversity of South Carolina
Robert G. WeaverArnold School of Public Health, University of South Carolina
Jennifer R. O’NeillUniversity of South Carolina
Xuewen WangUniversity of South Carolina – Columbia
International Journal of Exercise Science 15(7): 1538-1553, 2022.
DOI: 10.70252/DJFQ6358

Abstract

Higher wear compliance has been seen with wrist placed accelerometers versus hip placed. Performance of wrist placed ActiGraph GT3X+ accelerometer (GT3X+, ActiGraph LLC, Pensacola, FL) in assessing physical activity (PA) remains unclear. PURPOSE: This study examined GT3X+’s performance in measuring PA energy expenditure (PAEE) and classifying PA intensity in older women. METHODS: Women [n = 89, age = 65.6 (4.3)] wore GT3X+ and SenseWear Armband Mini (SWAM, BodyMedia Inc. Pittsburgh, PA) for 2 weeks. Concurrently, doubly labeled water (DLW) determined total daily energy expenditure (TDEE). Resting energy expenditure (REE) was determined by Indirect Calorimetry. Data was processed using manufacturer-provided software. Bivariate correlations, Intra Class Correlations, and Bland-Altman plots were performed to evaluate agreement between GT3X+ and criterion measures for sedentary time, light and moderate-to-vigorous PA (determined by SWAM) and PAEE (determined by SWAM and by DLW and REE). Epoch-by-epoch analysis evaluated discrepancy and agreement of PA intensity classification between GT3X+ and SWAM. RESULTS: For PAEE, GT3X+ showed moderate correlations with criterion measures (= 0.413, 0.400 with SWAM; r = 0.564, 0.501 with DLW and REE), but Bland-Altman plots showed large variability. When estimating time spent in PA intensity, GT3X+ underestimated sedentary time and overestimated PA intensity compared to SWAM. During epoch-by-epoch analysis, GT3X+ misclassified light intensity PA as moderate-to-vigorous PA 72% of the time. Counts per minute showed strong correlations with criterion measures (r = 0.68, 0.625 for SWAM and DLW and REE respectively). CONCLUSION: Current equations and cut points do not provide accurate measures of PA with wrist-worn GT3X+ in older women.

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