title: Validation of Consumer-Based Hip and Wrist Activity Monitors in Older Adults With Varied Ambulatory Abilities.
abstract: The accuracy of step detection in consumer-based wearable activity monitors in older adults with varied ambulatory abilities is not known.
  
  
  
  We assessed the validity of two hip-worn (Fitbit One and Omron HJ-112) and two wrist-worn (Fitbit Flex and Jawbone UP) activity monitors in 99 older adults of varying ambulatory abilities and also included the validity results from the ankle-worn StepWatch as a comparison device. Nonimpaired, impaired (Short Physical Performance Battery Score < 9), cane-using, or walker-using older adults (62 and older) ambulated at a self-selected pace for 100 m wearing all activity monitors simultaneously. The criterion measure was directly observed steps. Intraclass correlation coefficients (ICC), mean percent error and mean absolute percent error, equivalency, and Bland-Altman plots were used to assess accuracy.
  
  
  
  Nonimpaired adults steps were underestimated by 4.4% for StepWatch (ICC = 0.87), 2.6% for Fitbit One (ICC = 0.80), 4.5% for Omron HJ-112 (ICC = 0.72), 26.9% for Fitbit Flex (ICC = 0.15), and 2.9% for Jawbone UP (ICC = 0.55). Impaired adults steps were underestimated by 3.5% for StepWatch (ICC = 0.91), 1.7% for Fitbit One (ICC = 0.96), 3.2% for Omron HJ-112 (ICC = 0.89), 16.3% for Fitbit Flex (ICC = 0.25), and 8.4% for Jawbone UP (ICC = 0.50). Cane-user and walker-user steps were underestimated by StepWatch by 1.8% (ICC = 0.98) and 1.3% (ICC = 0.99), respectively, where all other monitors underestimated steps by >11.5% (ICCs < 0.05).
  
  
  
  StepWatch, Omron HJ-112, Fitbit One, and Jawbone UP appeared accurate at measuring steps in older adults with nonimpaired and impaired ambulation during a self-paced walking test. StepWatch also appeared accurate at measuring steps in cane-users.
authors.affiliation: School of Nursing, University of North Carolina-Chapel Hill.|School of Nutrition and Health Promotion, Arizona State University, Phoenix.
authors.forename: Theresa A
authors.initials: TA
authors.lastname: Floegel
authors.affiliation: School of Nutrition and Health Promotion, Arizona State University, Phoenix.|Departamento de Formación, Pontificia Universidad Javeriana, Bogota, Colombia.
authors.forename: Alberto
authors.initials: A
authors.lastname: Florez-Pregonero
authors.affiliation: School of Nutrition and Health Promotion, Arizona State University, Phoenix.
authors.forename: Eric B
authors.initials: EB
authors.lastname: Hekler
authors.affiliation: School of Nutrition and Health Promotion, Arizona State University, Phoenix. matthew.buman@asu.edu.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Buman
mesh_terms: D061725:Accelerometry; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D014953:Wrist / Q000502:physiology*
keywords: Accelerometer; Accuracy; Exercise; Pedometer; Physical activity