Aims. – Determination of critical power (CP) from a single test. Current knowledge. – Recent research has been conducted on the utility of all-out exercise to identify parameters of physiological function. This has led to the development of a protocol that would provide a means of measuring CP, that is, the lower boundary for severe exercise, in a single test. Indeed, our recent findings highlight that all-out exercise of 90 s (as the “Wingate” test) are too short for CP to be attained at the end of the exercise while the end power of a 3-min test has been shown to equal CP. The present review presents the methodological considerations to address prior to prolonged all-out exercise testing on cycle ergometers. Prospects. – We conclude by considering the possible applications of our findings to sports performance and the directions for future research in this area.