Garmin wearable device offers reliable alternative for on-water stroke rate and velocity measurement in rowing

Performance tracking devices in the form of wrist-worn watches are common in rowing; however, the accuracy of relevant output variables (i.e. stroke rate [SR] and velocity) during on-water training is unknown. To assess the quality of wrist-watch data output, 16 rowing athletes recorded 118 on-water rowing sessions using a Garmin Forerunner 735XT, which was compared to a Catapult Optimeye R4 tracking device. Garmin recording function was set to ‘Every Second’ (N = 68 sessions) or ‘Smart’ (N = 50 sessions). Catapult velocity was calculated as the average velocity per stroke, while a 15 s velocity moving average was determined for Garmin data. Catapult and Garmin were filtered for training-specific data (SR = 14–50 strokes per minute [spm]; velocity = 2.1–7.0 m/s⁻¹). Efficacy and reliability of the Garmin was assessed via the difference between devices (% error), intra-class correlation coefficient (ICC ± 95% confidence interval (CI)) and coefficient of variation (CV%). Error in 15 s smoothed velocity was 3.8% (‘Every Second’) and 8.2% (‘Smart’). Both recording functions demonstrated ‘good’ reliability (ICC = 0.75–0.9, CV < 10%) for SR and velocity; the exception was SR using ‘Smart’ recording. Our data suggests that when using the ‘Every Second’ recording function, data is filtered and velocity is smoothed over 15 s, the Garmin device can be reliable for SR and velocity measurement within 1 spm and <0.20 m/s⁻¹ respectively.