title: Concurrent validation of the Actigraph gt3x+, Polar Active accelerometer, Omron HJ-720 and Yamax Digiwalker SW-701 pedometer step counts in lab-based and free-living settings.
abstract: Activity monitors are frequently used to assess activity in many settings. But as technology advances, so do the mechanisms used to estimate activity causing a continuous need to validate newly developed monitors. The purpose of this study was to examine the step count validity of the Yamax Digiwalker SW-701 pedometer (YX), Omron HJ-720 T pedometer (OP), Polar Active accelerometer (PAC) and Actigraph gt3x+ accelerometer (AG) under controlled and free-living conditions. Participants completed five stages of treadmill walking (n = 43) and a subset of these completed a 3-day free-living wear period (n = 37). Manually counted (MC) steps provided a criterion measure for treadmill walking, whereas the comparative measure during free-living was the YX. During treadmill walking, the OP was the most accurate monitor across all speeds (±1.1% of MC steps), while the PAC underestimated steps by 6.7-16.0% per stage. During free-living, the OP and AG counted 97.5% and 98.5% of YX steps, respectively. The PAC overestimated steps by 44.0%, or 5,265 steps per day. The Omron pedometer seems to provide the most reliable and valid estimate of steps taken, as it was the best performer under lab-based conditions and provided comparable results to the YX in free-living. Future studies should consider these monitors in additional populations and settings.
authors.affiliation: a School of Kinesiology and Recreation, Illinois State University , Normal , IL , USA.
authors.forename: Joey A
authors.initials: JA
authors.lastname: Lee
authors.forename: Skip M
authors.initials: SM
authors.lastname: Williams
authors.forename: Dale D
authors.initials: DD
authors.lastname: Brown
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Laurson
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D015203:Reproducibility of Results; D016138:Walking; D055815:Young Adult
keywords: activity monitors; assessment; evaluation; measurement