摘要：Energy expenditure (EE) and step count (SC) was measured with a Fitbit Flex wrist-worn activity tracker (FWAT) during a two-day walking protocol. Forty-nine volunteers participated on day 1, 46 on day 2, 31 were used for reliability. Participants walked for 3 min at 1.5, 2.5, and 3.5 mph at 0% grade on both days. An Applied Electrochemistry MOXUS Metabolic System (MX) with steps counted was the baseline comparison. Data was analyzed using dependent t-tests (P<0.05) and Cronbach’s α (≥0.70). For EE; (1.5 mph; P<0.01, Standard Error(SE): FWAT 19.43 ± 0.73; MX 11.9 ± 0.32, α=0.56. 2.5 mph; P<0.01, SE: FWAT 25.0 ± 0.75; MX 14.43 ± 0.38, α=0.72. 3.5 mph; P<0.01, SE: FWAT 27.2 ± 0.77; MX 19.43 ± .049, α=0.67). For SC; (1.5 mph; P<0.01, SE: FWAT 231 ± 6.02; MC 269 ± 2.58, α=0.55. 2.5 mph; P=0.03, SE: FWAT 323 ± 4.39; MC 332 ± 2.18, α=0.50. 3.5 mph; P<0.01, SE: FWAT 366 ± 3.22; MC 380 ± 2.21, α=0.66). The FWAT significantly overestimated EE with reliability at 2.5 mph and significantly underestimated SC without reliability at any speed.
