Editing Archibald Hill (section)

== Muscle physiology ==
Hill made many exacting measurements of the heat released when skeletal muscles contract and relax. A key finding was that heat is produced during contraction, which requires investment of chemical energy, but not during relaxation, which is passive.<ref name="Katz1978" /> His earliest measurements used equipment left behind by the Swedish physiologist [[Magnus Blix]], Hill measured a temperature rise of only 0.003&nbsp;°C. After publication he learned that German physiologists had already reported on heat and [[muscle contraction]] and he went to Germany to learn more about their work. He continually improved his apparatus to make it more sensitive and to reduce the time lag between the heat released by the preparation and its recording by his [[thermocouple]]. 
 
Hill is regarded, along with [[Hermann Helmholtz]], as one of the founders of [[biophysics]].

Hill returned briefly to Cambridge in 1919 before taking the chair in physiology at the [[Victoria University of Manchester]] in 1920 in succession to [[William Stirling (physiologist)|William Stirling]]. Using himself as the subject — he ran every morning from 7:15 to 10:30 — he showed that running a dash relies on energy stores which afterwards are replenished by [[Excess post-exercise oxygen consumption|increased oxygen consumption]]. Paralleling the work of German [[Otto Fritz Meyerhof]], Hill elucidated the processes whereby mechanical work is produced in muscles. The two shared the 1922 Nobel Prize in Physiology and Medicine for this work.<ref>{{cite web | url=https://www.nobelprize.org/nobel_prizes/medicine/laureates/1922/hill-facts.html | title=The Nobel Prize in Physiology or Medicine 1922}}</ref> Hill introduced the concepts of [[VO2 max|maximal oxygen uptake]] and oxygen debt in 1922.<ref>{{Cite journal|last=Hale|first=Tudor|date=2008-02-15|title=History of developments in sport and exercise physiology: A. V. Hill, maximal oxygen uptake, and oxygen debt|journal=Journal of Sports Sciences|language=en|volume=26|issue=4|pages=365–400|doi=10.1080/02640410701701016|pmid=18228167|s2cid=33768722|issn=0264-0414}}</ref><ref>{{Cite journal|last1=Bassett|first1=D. R.|last2=Howley|first2=E. T.|date=1997|title=Maximal oxygen uptake: "classical" versus "contemporary" viewpoints|journal=Medicine and Science in Sports and Exercise|volume=29|issue=5|pages=591–603|issn=0195-9131|pmid=9140894|doi=10.1097/00005768-199705000-00002|doi-access=free}}</ref>