Physiological Breakpoints and Maximal Steady-State of Cycling

Scott C, Wyatt F, Winchester J, Williamson K, Welter A, Brown S. Physiological Breakpoints and Maximal Steady-State of Cycling. JEPonline 2015;18(3):33-45. The aim of this study was to examine various physiological thresholds and their association with maximal steady-state exercise. Elite level cyclists (n = 15) participated in the study. All data were collected on a Velotron cycle ergometer, lactate meter, metabolic cart, and a heart rate monitor. Blood lactate (mM), VO2 (mL·kg·min), and heart rate (beats·min) data were collected every minute for both the VO2 max test and the maximal steady-state test. Statistical analysis included the descriptive mean (±SD) of the subjects and the test results, the comparison of each physiological measurement and the mean (±SD) values, and t-tests analyzing the wattage corresponding to the said variable and physiological test. Statistical significance was set at P≤0.05. There was no noticeable trend of one threshold being indicative of another threshold. Heart rate and ventilatory thresholds displayed strong correlations with their respective values at steady-state intensity, while blood lactate values at threshold exhibited weak, but significant correlations to values obtained at steady-state efforts. The correlation shown in the study between heart rate threshold and ventilatory threshold and their respective values at steady-state can help provide evidence-based training information, which can lead to an increase in athletic performance by training the proper bioenergetic system.