To date, most initiatives to prevent sports injuries have been based on intuition rather than the solid experimental basis demanded by evidence based medicine.¹ For example, since many eye injuries are sustained in activities such as ice hockey and squash, it is inferred that protection of the eyes and/or face should be required of all playing these sports. Likewise, because many serious head injuries are sustained by cyclists, it is argued that legislation should be enacted to enforce the use of protective helmets by cyclists.

Such initiatives are logical and appear to have substantial preventive value, but because of limitations in the design of existing experiments, the magnitude of any protection remains unclear. Clear proof of benefit requires a valid measure of exposure to risk, an appropriate assessment of the incidence and extent of injury, random assignment of subjects to a well controlled intervention, and a careful statistical assessment of any protection that is observed. For potential health benefits to be realized, there is also a need to communicate a synopsis of available information to the general public, and to convince them of the merits of any proposed preventive measures.² These issues are here explored briefly, with particular reference to the …