Validity of the SenseWear Armband™ to assess energy expenditure in graded walking

Background: Accurate assessments of physical activity and energy expenditure (EE) are needed to advance research on positive and negative graded walking. Purpose: To evaluate the validity of two SenseWear™ Armband monitors (Pro3 and the recently released Mini) during graded walking. Methods: Twenty healthy adults wore both monitors during randomized walking activities on a motorized treadmill at seven grades (0%, ±5%, ±15% and ±25%). Estimates of total EE from the monitors were computed using different algorithms and compared to values derived from indirect calorimetry methodology using a 2-way mixed model ANOVA (Device x Condition), correlation analyses and Bland-Altman plots. Results: There was no significant difference in EE between the two armbands in any of the conditions examined. Significant main effects for device and condition as well as a consistent bias were observed during positive and negative graded walking, with a greater over- and under-estimation at higher slope. Conclusions: Both the armbands produced similar EE values and seem to be not accurate in estimation of EE during activities involving uphill and downhill walking. Additional work is needed to understand factors contributing to this discrepancy and to improve the ability of these monitors to accurately measure EE during graded walking.