While the reliability of running economy (RE) has been widely established, limited investigation has been carried out into the reliability of various performance variables during a RE test. Subsequently, the purpose of the current study was to examine the reliability of time-to-exhaustion (TTE) and rating of perceived exertion (RPE) during a RE test among trained runners and moderately endurance-trained men. Absolute V̇O2 (mL/minute), V̇O2 relative to body mass (mL/kg/minute), oxygen cost of running (CR) defined as V̇O2 relative to body mass raised to the power of 0.75 per meter (ml kg-0.75/m), heart rate (HR), ventilation (V̇E), carbon dioxide production (V̇CO2), respiratory exchange ratio and RPE were measured while treadmill running on two occasions at three discontinuous incremental speeds corresponding to 70%, 90%, and 110% of the second ventilatory threshold (VT2). The duration of the last increment was measured as TTE. The reliability was determined using the intraclass correlation coefficient (ICC) and 95% ratio limits of agreement. The intraindividual variability was examined using the coefficient of variation (CV). There were no significant differences between the two RE trials for absolute V̇O2, relative V̇O2, CR, V̇E, V̇CO2, respiratory exchange ratio and RPE (p ≥ 0.05) except for the differences in RPE during the first increment and the TTE (p < 0.05). The reliability was high for absolute V̇O2, relative V̇O2, CR, HR and TTE and was moderate for V̇E and RPE. Small intraindividual variability was found for absolute V̇O2, relative V̇O2, CR, HR and RPE. The findings will enable sport scientists to incorporate a variety of performance variables when examining RE. © 2012.
Doma, K., Deakin, G. B., Leicht, A. S., & Sealey, R. M. (2012). The reliability of running economy among trained distance runners and field-based players. Journal of Exercise Science and Fitness, 10(2), 90–96. https://doi.org/10.1016/j.jesf.2012.10.006