Blue plaque review series: A.V. Hill, athletic records and the birth of exercise physiology.

One hundred years ago, A.V. Hill authored three manuscripts analysing athletic world records from a physiological perspective. That analysis, grounded in Hill's understanding of contemporary muscle bioenergetics, provides a fascinating sketch of the thoughts and speculations of one of the fathers of exercise physiology. In this review, we reflect on Hill's prose with the benefit of 100 years of hindsight, and illustrate how Hill was able to draw startlingly accurate conclusions from what limited data were available on the physiology of intense exercise. Hill discusses the energetics of running, swimming, rowing and cycling in both males and females, as well as addressing exercise performance in horses and the mechanics of jumping. He also considers sports nutrition, pacing strategy and ultra-endurance exercise. Perhaps most impactfully, he establishes that the speed-duration relationship has characteristics that reflect the underlying physiological basis of exercise performance. That physiology, in turn, differs depending on the duration of the event itself, providing one of the first descriptions of the task-dependent nature of mechanisms limiting exercise tolerance. A remarkable feature of Hill's papers is that they were written just a few years before a major revolution in muscle biochemistry, and yet Hill was still able to develop conceptually sound ideas about human performance. His hypotheses require only minor revision to bring them into line with current understanding. In reaching their centenary, therefore, the surprising feature of these papers is not how well they have aged, but how relevant they remain.