Purpose There are important methodological considerations for translating wearable-based gait-monitoring data to field settings. This study investigated different devices` sampling rates, signal lengths, and testing frequencies for athlete monitoring using dynamical systems variables. Methods Secondary analysis of previous wearables data (N = 10 runners) from a 5-week intensive training intervention investigated impacts of sampling rate (100-2000 Hz) and signal length (100-300 strides) on detection of gait changes caused by intensive training. Primary analysis of data from 13 separate runners during 1 week of field-based testing determined day-to-day stability of outcomes using single-session data and mean data from 2 sessions. Stride-interval long-range correlation coefficient a from detrended fluctuation analysis was the gait outcome variable. Results Stride-interval a reduced at 100- and 200- versus 300- to 2000-Hz sampling rates (mean difference: -.02 to -.08; P = .045) and at 100- compared to 200- to 300-stride signal lengths (mean difference: -.05 to -.07; P < .010). Effects of intensive training were detected at 100, 200, and 400 to 2000 Hz (P = .043) but not 300 Hz (P = .069). Within-athlete a variability was lower using 2-session mean versus single-session data (smallest detectable change: .13 and .22, respectively). Conclusions Detecting altered gait following intensive training was possible using 200 to 300 strides and a 100-Hz sampling rate, although 100 and 200 Hz underestimated a compared to higher rates. Using 2-session mean data lowers smallest detectable change values by nearly half compared to single-session data. Coaches, runners, and researchers can use these findings to integrate wearable-device gait monitoring into practice using dynamic systems variables.
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