The regulation of the pacing strategy remains poorly understood, since much of classic physiology has focused on the factors that ultimate limit, rather than regulate exercise performance. When exercise is self-paced and work rate free to vary in response to external and internal physiological cues, then a complex system is proposed to be responsible for alterations in exercise intensity, possibly through altered activation of skeletal muscle motor units. The present review evaluates the evidence for such a complex system by investigating studies where interventions such as elevated temperature, altered oxygen content of the air, reduced fuel availability and misinformation about distance covered have resulted in alterations to the pacing strategy. The review further investigates how such a pacing strategy might be regulated for optimal performance, while ensuring that irreversible physiological damage is not incurred. Finally, it describes a novel model for how exercise performance is regulated by a combination of previous experience, afferent information and the conscious rating of perceived exertion. This model, termed the anticipatory feedback-RPE model, proposes that all forms of exercise are regulated by a system that incorporates both expectations of the exercise duration as well as physiological feedback, with the ultimate result that exercise is regulated in anticipation of bodily harm.