Running power meters and theoretical models based on laws of physics: Effects of environments and running conditions

Abstract

Training prescription and load monitoring in running activities have benefited from power output (PW) data offered by new technologies. Nevertheless, to date, the sensitivity of PW data provided by these tools is still not completely clear. The aim of this study was to analyze the level of agreement between the P_W estimated by five commercial technologies and the two main internationally theoretical models based on laws of physics, in different environments and running conditions. Ten endurance-trained male athletes performed three submaximal running protocols on a treadmill (indoor) and an athletic track (outdoor), with changes in speed, body weight, and slope. P_W was simultaneously registered by the commercial technologies Stryd (Stryd_App and Stryd_Watch), RunScribe, Garmin_RP and Polar_V, whereas theoretical power output (TP_W) was calculated by the two mathematical models (TP_W1 and TP_W2). Statistics included, among others, the Pearson's correlation coefficient (r) and standard error of measurement (SEM). The Polar_V, and above all Stryd, showed the closest agreement with the TP_W1 (Stryd: r ≥ 0.947, SEM ≤ 11 W; PolarV: r ≥ 0.931, SEM ≤ 64 W) and TP_W2 (Stryd: r ≥ 0.933, SEM ≤ 60 W; Polar_V: r ≥ 0.932, SEM ≤ 24 W), both indoors and outdoors. On the other hand, the devices Garmin_RP (r ≤ 0.765, SEM ≥ 59 W) and RunScribe_. (r ≤ 0.508, SEM ≥ 125 W) showed the lowest agreement with the TP_W1 and TP_W2 models for all conditions and environments analyzed. The closest agreement of the Stryd and Polar_V technologies with the TP_W1 and TP_W2 models suggest these tools as the most sensitive, among those analyzed, for P_W measurement when changing environments and running conditions.

Keywords: Accelerometer; Biomechanics; Endurance; Physiology; Variability.