Validity and reproducibility of commercial cycling power meters in hot and cold environmental temperatures

Abstract

Power meters are a training tool used to help cyclists improve performance by objectively monitoring intensity. Some power meters are well established and validated, whereas others are relatively new. Most power meters have been tested for validity and reliability in laboratory and field settings of similar conditions; however, the reproducibility of these power meters across different temperatures has not been established. To examine the potential differences of the CompuTrainer, PowerTap, Stages, and Vector power meters in hot and cold compared to a room temperature environment. Recreationally trained male (n=7) and female (n=3) participants each completed three incremental cycling trials in hot (33°C), cold (7°C), or room temperature (RT, 20°C) conditions. The power meters were placed on a standard road bicycle and power output was logged and recorded. The CompuTrainer was higher in the room temperature trial compared to the cold and the hot, but not between the hot and cold trial. The PowerTap was not different in RT and cold, but was lower in hot compared to RT and compared to cold. The Stages was not different between RT and cold, but was lower in the hot compared to RT and compared to cold. The Vector was not different between RT and cold but was lower in the hot compared to RT and compared to cold. These data indicate that environmental temperature may affect the reproducibility of power meters. It is important to recognize the potential differences between temperatures when choosing a power meter.

Interchangeability between the Data Obtained by Two Powermeters during Road Cycling Competitions: A Case Study

“…The second variable was the highest mean power that the cyclist held for a given period (i.e., twelve periods from 1 s to 60 min). Additionally, critical power, which was defined as the power asymptote of the hyperbolic relationship between power output and time to exhaustion [ 9 ], was also obtained from the power output profile, as previous studies did [ 6 ]. Finally, Normalized power, defined as the power output the cyclist could sustain if intensity were maintained constant without any variability [ 12 ].…”

“…Consequently, Maier et al [ 3 ] observed that the power output registered by different power meters is highly variable (even when they have been designed by the same manufacturer) and recommend further studies in field conditions with changes in ambient temperature, vibrations, or gear shifts. Shute et al [ 6 ] observed that environmental temperature affected the registry of various power meters. Furthermore, Bouillod et al [ 5 ] demonstrated that vibration and field conditions affect the power output measured.…”

Caveats and Recommendations to Assess the Validity and Reliability of Cycling Power Meters: A Systematic Scoping Review

“…In addition, Gardner, Stephens, Martin, Lawton, Lee, and Jenkins [ 42 ] stated that both the SRM and PowerTap power meters are sensitive to differences in temperature. More recently, Shute et al [ 178 ] compared four systems (CompuTrainer, PowerTap Hub, Stages crank, and Garmin vector) in three different environmental conditions of temperature, cold 7°, regular 20°, and hot 33°. In this study, the authors observed a significant alteration of accuracy for PowerTap, Vector, and Stages, especially in the hot situation.…”