Jessica A. Insogna

Validity and reliability of Fitbit activity monitors compared to ActiGraph GT3X+ with female adults in a free-living environment

OBJECTIVES Inexpensive activity monitors have recently gained popularity with the general public. Researchers have evaluated these consumer-based monitors in laboratory-conditions. Given the current wide-spread consumer use of these devices, it is important to ensure users are attaining accurate information compared to previously validated measures. This study investigates the accuracy of Fitbit One and Flex activity monitors in measuring steps, sedentary time, and time spent in light, moderate, and vigorous intensity activities with ActiGraph GT3X+ with female adults in free-living conditions. DESIGN Cross-sectional study. METHODS Twenty-two women, 21.23±1.63 years, BMI: 22.35±2.34kg/m2 wore two Fitbit Ones (bra and waist), one Fitbit Flex on the wrist, and one ActiGraph GT3X+ on the waist for seven-consecutive days. Repeated measures ANOVA was used to explore differences in steps, sedentary time, and time spent in light, moderate and vigorous intensity activities among the four devices. RESULTS No differences were found in number of steps recorded across the four devices. Fitbit One, waist and bra, overestimated time spent in light intensity activities. Fitbit One (waist) and Fitbit Flex overestimated time spent in moderate intensity activities. Fitbit One, waist and bra, and Fitbit Flex overestimated time spent in vigorous intensity activities. All Fitbit activity monitors overestimated MVPA and underestimated sedentary time compared to the ActiGraph. CONCLUSIONS Regardless of wear-location all Fitbit devices provide similar activity monitoring and users can wear the devices wherever best accommodates their lifestyle or needs. Users should not rely solely on these monitors when tracking vigorous and MVPA activities.

Transfer of Off-Ice Agility to On-Ice Performance in Elite Canadian Collegiate Hockey Players: 3014 Board #79 June 3, 3: 30 PM - 5: 00 PM.

METHODS: Wingate test results from the summer training periods and 1500m performances during the subsequent winter were analyzed over a 3-year period, in 5 female and 8 male elite speed skaters. Regression analyses using generalized estimating equations (GEE) were used to estimate the relation between Wingate test variables and 1500m performance. Wingate peak power (PP), mean power (MP) and fatigue index (FI) were used to predict 1500m time, split times and lap times. RESULTS: The results indicate that an improvement of 1 W/kg on PP and MP in women predict an improvement of -0.75s and -2.05s, respectively, on 1500m time (World Record 111.79s). In men, PP and MP were also associated with performance, predicting improvements of -0.2s and -2.33s on 1500m time per 1 W/kg (World Record 101.04s). Split times on the 1500m in women were also associated with Wingate PP and MP. CONCLUSION: These data indicate that Wingate tests performed during the summer training period are a good predictor of 1500m speed skating performance in the subsequent winter. Relative to the World Records on 1500m, a 1 W/kg improvement in MP predicts a 2% improvement in performance.