JEPonline Perceptual and Physiological Fatigue Thresholds during Cycle Ergometry

Cochrane KC, Housh TJ, Bergstrom HC, Jenkins NDM, Johnson GO, Schmidt RJ, and Cramer JT. Perceptual and Physiological Fatigue Thresholds during Cycle Ergometry. JEPonline 2014;17(5): 95-107. Thirteen subjects (mean ± SD age: 21.8 ± 2.6 yrs) performed an incremental cycling test and 4, 8-min submaximal rides (65 to 80% of VO2 peak) to: (a) compare power outputs and relative intensities that corresponded to the gas exchange threshold (GET), ventilatory threshold (VT), respiratory compensation point (RCP), physical working capacity (PWC) at oxygen consumption PWCVO2, heart rate (PWCHRT), and rating of perceived exertion (PWCOMNI) thresholds; and (b) examine the relationships among the fatigue thresholds and the exercise intensity domains. The RCP (184 ± 47 W) was significantly (P≤0.0033) greater than the GET (142 ± 38 W), VT (143 ± 40 W), PWCVO2 (106 ± 34 W), PWCHRT (108 ± 34 W), and PWCOMNI (112 ± 34 W). The GET and VT were significantly greater than the PWCVO2, PWCHRT, and PWCOMNI, but there were no differences among the PWCVO2, PWCHRT, and PWCOMNI. These findings suggest that the PWCVO2, PWCHRT, and PWCOMN fell within the moderate intensity domain, and share a common physiological mechanism that was different from those associated with the GET, VT, and RCP.