Stryd Get More Scientific Accuracy Validation

Stryd delivers a stable, sensitive, and reliable metric

[Stryd delivers] a stable, sensitive, and reliable metric that can estimate aerobic fitness, delineate exercise intensities, and approximate the metabolic requirements of running near the MLSS.

Science Link: mdpi.com

There is no consensus on how to evaluate mechanical running power output, thus the different models used by Garmin, Apple, Polar and Coros result in a WIDE range of values at any given speed. When running on the flat power measurements can be derived from “external” or “internal” work perspectives by evaluating the centre of mass (CoM) or the body segments, respectively. Amongst other difficulties, these approaches require technologically capable sports laboratories to assess the forces and movements involved. Contrast to cycling, where there is a strong relationship between mechanical and metabolic power.

Clearly power is a useful training metric from several perspectives. Stryd has been widely reported and believed to provide the closest relationship with VO2 to any other tool [anecdotally I have had this confirmed by Stryd competitors!] I and many others suggest that Stryd power can be used as a reliable proxy for metabolic power even when taking into consideration numerous (most) environmental conditions.

This published study by van Rassel et al (University of Calgary) assessed the Stryd (Boulder, CO) running power metric in a controlled environment. The team evaluated the stability, sensitivity, and reliability of Stryd at stable metabolic work rates to determine the efficacy of Stryd running power as a training intensity and running performance metric. They also explored the relationship between running power and running economy, estimated mechanical efficiency during constant-speed treadmill running, and contrasted steady-state measurements with measurements derived from incremental exercise. The researchers tested the hypothesis that Stryd running power would meet several criteria as a valid training tool.

Summary of Findings

We sought to determine the utility of Stryd, a commercially available inertial measurement unit, to quantify running intensity and aerobic fitness. Fifteen (eight male, seven female) runners (age = 30.2 [4.3] years; VO₂max = 54.5 [6.5] ml·kg⁻¹·min⁻¹) performed moderate- and heavy-intensity step transitions, an incremental exercise test, and constant-speed running trials to establish the maximal lactate steady state (MLSS). Stryd running power stability, sensitivity, and reliability were evaluated near the MLSS. Stryd running power was also compared to running speed, V·O₂, and metabolic power measures to estimate running mechanical efficiency (EFF) and to determine the efficacy of using Stryd to delineate exercise intensities, quantify aerobic fitness, and estimate running economy (RE). Stryd running power was strongly associated with VO₂ (R² = 0.84; p < 0.001) and running speed at the MLSS (R² = 0.91; p < 0.001). Stryd running power measures were strongly correlated with RE at the MLSS when combined with metabolic data (R² = 0.79; p < 0.001) but not in isolation from the metabolic data (R² = 0.08; p = 0.313). Measures of running EFF near the MLSS were not different across intensities (~21%; p > 0.05). In conclusion, although Stryd could not quantify RE in isolation, it provided a stable, sensitive, and reliable metric that can estimate aerobic fitness, delineate exercise intensities, and approximate the metabolic requirements of running near the MLSS.

STRYD Review, 10,000km Update – (Dual-) Running Power ⚡ Pod