ABSTRACT
A high V̇O2 max is a pre-requisite of elite performance in some sports but success in many sports relies as much on the ability to sustain performance at or below various levels of submaximal exercise as on maximal performance. This chapter describes physiological and metabolic responses to exercise of increasing intensity and analyses submaximal, sport-related indicators of aerobic fitness and exercise performance. The development, trainability, and application to youth sport of blood lactate and gas exchange thresholds, critical power (or critical velocity), and running economy are critically examined.
