Why should a journal of sports and exercise medicine include an extensive series of papers that deal exclusively with exercise physiology; indeed with a tiny subsection of that discipline? The reason is perhaps twofold. The first is that the published articles all address the novel aspects of exercise-induced fatigue and the regulation of human exercise performance.

Fatigue remains a common complaint that brings patients to their primary care physicians. Surely there must be some common explanation for the types of fatigue that we feel, whether at rest or during exercise? Can the exercise sciences contribute something unique to our understanding of this important clinical phenomenon?

In 1923, Nobel Laureate Archibald V Hill developed the currently popular model of exercise fatigue.1 According to his understanding, fatigue develops in the exercising skeletal muscles when the heart is no longer able to produce a cardiac output which is sufficient to cover the exercising muscles' increased demands for oxygen. This causes skeletal muscle anaerobiosis (lack of oxygen) leading to lactic acidosis. The lactic acid so produced then ‘poisons’ the muscles, impairing their function and causing all the symptoms we recognise as ‘fatigue’. The collection of articles in this issue provides several invigorating challenges to Hill's hallowed interpretation. Which brings us to the second reason why these articles are published here rather than elsewhere. For some of the articles included were reviewed unfavourably elsewhere; perhaps they were considered heretical. Clearly, some believe that ideas challenging a hallowed dogma are best left unpublished. Otherwise, we might need to update our thinking. Or worse, our teaching!