Wearable power meters are increasingly popular among runners with Coros and Stryd offering running power as a real-time, trackable of a metric. PURPOSE: This study compared running power (RP) to physiological measures, heart rate (HR) and oxygen consumption (VO2), across high and low intensity running intervals. METHODS: Thirteen adult participants (n = 6 male; height = 174.9 ± 6.9 cm; mass = 72.5 ± 12.0 kg) were equipped with a Stryd 27 RP meter, a Polar H10 HR monitor, and a Cosmed K5 portable metabolic unit. Participants’ self-selected RP was obtained during a 10-min run on an indoor track (10 laps/mile). After resting for five minutes, participants ran another 10 min, alternating between equal intervals of RP 20% higher and 20% lower than self-selected RP: 120 s × 2, 60 s × 2, 30 s × 4, and 15 s × 8. All devices were started simultaneously before each run. RP (W/kg) was sampled at 1 Hz. HR (bpm) and VO2 (mL/kg/min) were sampled at 0.1 Hz throughout the interval run. Data were analyzed from the 60 s mark through the end of the run. HR and VO2 data were interpolated to 1 Hz, and cross correlations (max lag = 60 s) were used to compare RP, HR, and VO2 (mean values in Table 1). RESULTS: There were weak to moderate correlations between RP and VO2 (r = 0.351; lag = -29.1 s), RP and HR (r = 0.475; lag = 9.38 s), and HR and VO2 (r = 0.572; lag = -29.1 s; Table 2). CONCLUSION: HR showed the strongest correlation and smallest time delay with RP. This may be practically useful because HR data is more readily available to runners than VO2. However, the correlation is only moderate. While related, the three metrics of running intensity are fundamentally different. When exercising at a moderate intensity, changes in HR or VO2, which take seconds to minutes to stabilize, may be less evident than changes in mechanical power, which are immediate. Thus, it is possible that HR and VO2 would show a stronger relationship with RP across intervals longer than the 120 s maximum observed here. While RP can be a useful metric, it may not be informative about physiological responses to running especially over short intervals or when running at high intensity.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.