Lisa A. Simpson, Janice J. Eng, Tara D. Klassen , Shannon B. Lim , Dennis R. Louie , Beena Parappilly, Brodie M. Sakakibara, Dominik Zbogar
Rehabilitation Science, University of British Columbia, Canada
DOI: 10.2340/16501977-1993

Objective: It is important for older adults to be physically active, but many older adults walk slowly. This study examined the accuracy of a commercially available step-count device (Fitbit One) at slow speeds and compared the accuracy of the device when worn at the ankle and waist in older adults.
Methods: The Fitbit One was placed at the ankle and waist of participants (n=42; mean age 73 years) while they performed walking trials at 7 different speeds (0. 3–0. 9 m/s). Step counts obtained from video recordings were used as the gold standard comparison to determine the accuracy of the device.
Results: The ankle-worn device had significantly less error than the waist-worn device at all speeds. The percentage error of the ankle-worn device was less than 10% at speeds of 0. 4–0. 9 m/s and did not record zero steps at any speed. The percentage error of the waist-worn device was below 10% at only the 2 fastest speeds (0. 8 and 0. 9 m/s) and recorded zero steps for numerous participants at speeds of 0. 3–0. 5 m/s.
Conclusion: The Fitbit One can accurately capture steps at slow speeds when placed at the ankle and thus may be appropriate for capturing physical activity in slow-walking older adults.