The biological basis of aptitude: the endurance runner

Abstract

Summary: Aptitude for a particular sport is governed by many factors, not least of which are obvious environmental influences. There are, however, individuals who, through genetic endowment, have the necessary biological characteristics which identify them as potentially elite athletes. These characteristics have been described more fully for endurance athletes because prolonged, almost steady-state running, lends itself more readily to investigation by biologists, than do the more complex sports.These studies show that the potentially elite endurance athlete is an individual endowed with an above average cardio-respiratory system, capable of a high rate of oxygen transport and carbon dioxide elimination. Not only does the elite endurance athlete have a greater rate of oxygen transport than the average sportsman or sportswoman, but the muscles receiving the oxygen are composed mainly of type I, i.e. low-twitch oxidative fibres, which are designed for endurance exercise. Furthermore, the elite endurance athlete also appears to be pre-programmed genetically to lay down less fat, in the form of sub-cutaneous adipose tissue, than the average sportsman or sportswoman of the same age and sex.Although genetic endowment dictates the potential ability of an individual for sustained high speed running, only appropriate training will allow the realization of this potential and so enable the individual to join the fraternity of the world's elite endurance athletes.