The role of sport is considered in the light of the health and physical capabilities of the average members of the population. It is shown how the different aspects of physical capacity can be extended, not only in the average sedentary person, but also in the elderly and the physically incapacitated. The efficacy of sport in the prevention of disease is also discussed.

This paper examines urban-rural differences in the fertility of Pakistani women, as shown by the 1975 Pakistan Fertility Survey, part of the World Fertility Survey. The urban fertility rates were slightly higher than the rural rates. Urban marital fertility exceeded rural marital fertility at the younger reproductive ages, mainly on account of shorter duration of breast-feeding, which reduces birth intervals, but fell below it at the older reproductive ages. The beginnings of parity-specific birth control are discernible at the older reproductive ages in urban areas.

The contribution of mental health to sports performance in sports populations is discussed. Athletes' psychological needs and problems, and the various ways in which these may be resolved, are considered.

The benefits of physical activity in the treatment of psychiatric populations and the elderly are reviewed.

Recent emphasis on sports participation for its intrinsic rewards and the psychological benefits derived are also considered, and attention is drawn to the particular needs of children.

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.