Assessment of Activity Monitor Placement During Free‐Living Conditions

Abstract

Despite the popularity of consumer‐based physical activity monitors (AMs), many of these AMs have little data examining their comparability when worn on different body locations.PURPOSEOur study's purpose was to determine placement‐related differences of a popularly available AM for estimating steps, Calories (kcals), distance traveled, active minutes, and sleep time in a free‐living setting.METHODSParticipants (n=48) aged 18–28 years completed an unstructured, free‐living protocol in which participants wore two identical AMs (the Fitbit Flex or Fitbit Flex2), one on the non‐dominant (ND) wrist and one on the dominant (D) wrist, for five days. Participants were given the AMs early Monday morning and then instructed to return them Friday afternoon. Participants were instructed to wear the AMs 24 hours per day during all of their regular daily activities excluding contact sports and water‐based activities. Data were averaged across the three full days (Tuesday‐Thursday) and compared between wrists using paired t‐tests for each of the five recorded variables (steps, kcals, distance traveled, active minutes, and sleep time). Additionally, mean absolute difference (MAD) and mean absolute percent difference (MAPD) were calculated to assess differences between wrists.RESULTSThe AMs had varied results in recording steps, kcals, distance traveled, active minutes, and sleep time in the comparison of the ND and D wrist locations. For all variables, estimates from the ND wrist were higher than the D wrist. AM step differences were significantly different with MAD of 664.7 steps/day (MAPD of 6.7%; p<0.001), kcals had an MAD of 53.4 kcals/day (MAPD of 2.1%; p<0.001), distance had MAD of 0.3 miles/day (MAPD of 6.8%; p<0.001), and active minutes had an MAD of 7.3 minutes/day (MAPD of 36.5%; p<0.001). Participant sleep duration trended toward statistical significance (p=0.22) with an MAD of 23.8 minutes/day (MAPD of 5.9%) between wrists.CONCLUSIONData collected from AMs placed on the ND and D wrists were not equivalent. While differences for some variables were relatively small, others were substantial. Caution is warranted when wearing AMs on different wrists despite the seemingly all purpose and multi‐locational nature of AMs. Future research should investigate other AM placements and optimum conditions for use.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.