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Gazzetta Medica Italiana Archivio per le Scienze Mediche 2018 September;177(9):417-24

DOI: 10.23736/S0393-3660.17.03648-8


lingua: Inglese

A preliminary comparison of physical activity intensity classification and step counts between the Fitbit Zip and Actical accelerometer during treadmill locomotion

Ling-Yin LIANG 1 , Nancy GETCHELL 2, 3

1 Department of Physical Therapy, University of Evansville, Evansville, IN, USA; 2 Biomechanics and Movement Science Program, University of Delaware, Newark, DE, USA; 3 Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, USA


BACKGROUND: The purpose of this study was to compare the FitBit Zip to the Actical accelerometer in both children and adults during treadmill walking and running at specific speeds.
METHODS: Fifteen healthy children and 20 healthy adults simultaneously wore an Actical accelerometer and FitBit Zip while performing 5 minutes of quiet sitting followed by 5-minute conditions of slow, medium, and fast physical activity on a treadmill. The classification of physical activity intensity (sedentary, light, moderate, vigorous) of each device was compared using Chi-Square Goodness of Fit analyses to determine if the devices classified conditions similarly. FitBit Zip step counts were also compared to manually counted steps derived from video analysis. Two-way repeated measures ANOVAs with correction adjustment were used to compare step counts for each activity level for children and adults.
RESULTS: The FitBit Zip had variable performance in intensity classification in slow and medium conditions whereas the Actical provided stable classifications within each condition (P<0.001 for adults, children). More specifically, the FitBit Zip indicated higher percent time spent in moderate and vigorous activity levels than the Actical in slow and medium conditions.
CONCLUSIONS: The FitBit Zip appears to be satisfactory in its ability to calculate step count in children and in adults, except during light activity. Consumers should not rely on the FitBit Zip when tracking activity intensity levels.

KEY WORDS: Child - Physical fitness - Technology

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