Validity and reliability of STRAVA segments: Influence of running distance and velocity

This study aimed to assess the reliability of Strava measurements when manipulating segment distance and running velocity. The tests were carried out on a flat and straight segment. Ten male regular runners were equipped with a Garmin® Forerunner 945 watch and ran over a distance of 1 km of four increasing speeds: 1.39, 2.78, 4.17 and 5 m/s. Different reference positions were accurately determined in order to calculate time at 100 m, 200 m, 500 m, 700 m, and 1000 m. A bike with a wide angle camera was used to standardize the run pace and to record the entire run for reference measurements. Results show a high level of reliability with nearly perfect intra-class correlation (from .997 to 1) when data is analysed accordingly to the distance of the segment or to the running velocity. The validity is also very good with a small average bias (-0.25 s), a standard deviation of differences of 1.84 sec and the limit of agreement range from-3.86 to 3.35 sec. Regardless of the length of the segment, the actual performance of the runner is normally within +/-2 seconds of the results given by the Strava application. In 95% of cases, the measurement error will be less than four seconds. The relative error is proportionally larger for short segments done at a fast pace. Further studies are needed to explore Strava segments reliability in other specific contexts.