• exercise
• sport

A lack of adequate and regular physical activity is now recognised as a major factor contributing to many forms of chronic disease,^1–3 and public health agencies around the world are eager to encourage the general population to become more active.^4–6 However, papers such as those of Conn and associates,⁷ and repeated surveys from various countries, including Britain,⁸ Denmark,⁹ France,¹⁰ Finland,¹¹ Germany,¹² South Africa,¹³ and the US¹⁴ note an important social and economic toll from injuries among current exercisers. Some authors have suggested that the incidence of such adverse consequences could be sufficient to counter⁸ both health and economic arguments for the advocacy of exercise,¹⁵ whereas others have considered these injuries an inevitable consequence of participation in health giving exercise.^16,17 A journal such as Injury Prevention can hardly accept the position that such events are unavoidable “accidents”. Nevertheless, it seems appropriate to question both the magnitude of the problem and the ability to generalise the findings, while suggesting appropriate preventive measures.

As Conn and associates point out, the conclusions that can be drawn from a given survey are limited by problems of recall and seasonal effects.⁷ When attempting to generalise conclusions to other countries, we must add issues associated with differences in legislation, environmental conditions, and the popularity of various sports. For instance, in some countries the wearing of protective equipment may be mandatory, limb injuries in field sports may be increased by frozen playing surfaces, or a given type of activity may result in few injuries because most young men do not play this particular sport.

There is great difficulty in assessing the severity of injuries from survey data, even within a specific country. There can be little argument in the event of a fatality, but it is much less certain that “one or more days” of absence from school or work⁷ implies a severe injury. The true explanation of a day spent within the confines of the medical system could lie in such current issues as a litigious society, the practice of defensive medicine, and time lost through the poor organisation of health services.

Many reports such as those of Conn and associates⁷ also lack a denominator expressing the extent of exposure to various types of activity. Those concerned with injury prevention need detailed information concerning each patient’s body build, physical fitness, typical level of competition, cumulative hours of exposure to a given sport, and immediate environmental conditions as a prelude to deciding which combinations of athletic pursuit, intensity, and environment are potentially dangerous.^18,19 Differences in exposure to specific sports could explain some of the apparent ethnic differences in susceptibility to injury in the US.⁷ The main cause of the striking age and gender gradients in injury statistics probably lies in a combination of lack of experience, testosterone-mediated aggressiveness and inappropriate social conditioning among adolescent males, but it is again likely that such influences are tempered by age and gender related differences in the intensity and duration of exposure to dangerous sports.

Even more importantly, current assessments of the risk of a sport induced injury are based on data from individuals who have themselves chosen to adopt specific patterns of exercise. Such assessments are unlikely to reflect the risk of adverse health effects and associated medical costs among those who might be persuaded to increase their current level of physical activity through government propaganda. This point is well illustrated by a quasiexperimental study that compared health outcomes between an office that instituted a moderate aerobic fitness programme for their employees, and a matched control office where there was no such initiative.²⁰ Employees at the company where the fitness programme was introduced showed no increase in Ontario Health Insurance Plan billings for either orthopedic or cardiovascular services, either relative to their personal experience during the previous year, or relative to billings for employees of the control company during the same year. Indeed, the introduction of the fitness programme appeared to reduce the immediate medical costs of the experimental sample by the equivalent of about three physician visits and a half day of hospital care per employee year.²⁰

Most sports injury statistics are undoubtedly inflated by the problem of self selection. Lesions are most likely in boys and young men. Many in this group enjoy taking risks, and danger is a major factor attracting them to dangerous and extreme forms of sport. The discouraging reality is that even if we were to eliminate the risks associated with such forms of sport, it is likely that the participants would then choose to gain an “adrenaline rush” by adopting some other hazardous type of activity, such as driving on an expressway at an aggressive 200 km/h.

This is not to deny our responsibility to implement simple methods of reducing the risk of exercise induced accidents. A first step must be to develop adequate statistics, so that we can rank the various potential activities in terms of risk; then we can encourage the adoption of those pursuits where the ratio of health benefit to risk is high. Brisk walking is a popular, low risk choice among the general population,²¹ and at least for the older half of our citizens, it confers many of the preventive medical dividends promised by riskier forms of physical activity.²² The attention of governments is now turning from the provision of costly sports facilities to encouraging the incorporation of such simple types of regular physical activity into normal daily life—the “active living” option.²³ Cycling to and from school or work is potentially a valuable component of active living, but in most communities there is a need to enhance the safety of such transportation through the provision of dedicated, attractive, and well lit walkways and cycle paths. The alarming toll of head injuries among cyclists could also be almost halved if other legislatures were to follow the initiative of some Canadian provinces by making the wearing of cycle helmets compulsory.²⁴

Some people will continue to find their motivation to an active lifestyle through the excitement of competitive sport, or the pursuit of individually challenging objectives. The risk to such individuals could still be substantially reduced through a careful matching of the exerciser’s abilities with that of the competitor or the environment, the refinement and enforcing of rules of fair play, good maintenance of grounds, and insistence on the wearing of appropriate protective equipment. We will continue to see some injuries and even fatalities among walkers, cyclists, football players and rock climbers alike, but we must be disturbed when the current incidence of fatalities could be greatly reduced through a simple application of our current knowledge.