SECTION I.—PHYSIOLOGY. 
THE PHYSIOLOGICAL BASIS OF 
ATHLETIC RECORDS. 
ADDRESS BY 
Proressor A. V. HILL, O.B.E., Sc.D., F.R.S., 
PRESIDENT OF THE SECTION. 
In the study of the physiology of muscular exercise there is a vast store 
of accurate information, hitherto almost unexploited, in the records of 
athletic sports and racing. The greatest efforts and the most intense care 
have been expended in making what are really experiments upon these 
subjects, and the results obtained represent what may justly be described 
as a collection of natural constants of muscular effort in the human race. 
It is the purpose of this address to discuss certain aspects of the data 
available in connection with various forms of racing, and to see how far 
physiological principles at present known underlie them. 
Sources of Information. 
The most complete set of records available, for a great variety of sports, 
is to be found in ‘ The World’s Almanac and Book of Facts,’ published 
by the New York World. Much of the information here presented was 
obtained from the 1925 edition of that work; similar but less extensive 
data can be found in our own Whitaker’s Almanack. In addition, various 
books on horse-racing, on swimming, and on rowing have been searched 
for suitable material. The study of such data is not new. In most cases, 
however, it has been carried out not from the physiological but purely 
from the statistical standpoint; insufficient knowledge of the under- 
lying physiological principles was available to make it profitable to ask 
for the why and wherefore. Recent developments, however, of the scien- 
tific study of muscular effort in man have indicated certain broad lines 
on which some at any rate of the relations so established can be explained. 
I will not deal further with the statistical analysis of the facts, beyond 
referring to an extremely interesting and suggestive collection of them 
given in a paper by A. E. Kennelly, entitled ‘ An Approximate Law of 
Fatigue in the Speed of Racing Animals,’ published in the Proceedings 
of the American Academy of Arts and Sciences, vol. xlii., p. 275, 1906. 
Some, indeed, of my data are taken directly from that paper. 
Fatigue as the Determining Factor. 
An important and interesting problem for any young athlete is presented 
by the question ‘ how fast can I run some given distance ?’ Themaximum 
speed at which a given distance can be covered is known to vary largely 
with the distance. What are the factors determining the variation of 
speed with distance? How far, knowing a man’s best times at two 
