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Defining a c r icke t in jury

While Orchard and colleagues 1,2 should be congratulated for their at tempt at developing an international consensus on the definition of a cricket-related injury, a broader look at tile literature on definitions of injury might have provided a more robust definition of a cricket injury.

Orchard ei al 1,2 define a cricket injury (or significant injury) as "any injury or other medical condition that either (a) prevents a player from being fully available for selection for a major match or (b) during a major match, causes a player to be unable to bat, bowl, or keep wicket when required by either the rules or the team's captain." While the definition proposed seems easy to implement in practice, it does not actually define what would be considered to be a cricket-related injury in terms of physical tissue damage, which is the basis of generally accepted definitions of injury, nor does it define what is a medical condition.

The confusion may stem from the theoretical versus the operational definitions of an injury. For example, one of the most common theoretical injury definitions defines an injury as being "...caused by acute exposure to physical agents such as mechanical energy, heat, electricity, chemicals, and ionizing radiation interacting with the body in amounts or at rates that exceed the threshold of h u m a n tolerance. In some cases (for example, drowning and frostbite), injuries result from the sudden lack of essential agents such as oxygen or heat ''3. However, to operationalise this definition of an injury, many injury professionals rely on the International Classification of Disease, 10th revision (ICD-10) injury and poisoning chapter XIX (S00-T98) 4 or the earlier ICD-9 external cause codes (800-999) 5 to define what constitutes an injury.

What is lacking for the Orchard et al injury definition for cricketers is how an injury would be specifically defined theoretically (ie, in terms of physical tissue damage), and then how such a definition would be operationalised (ie, how will physical tissue damage be consistently identified and recorded). Although latent effects of physical tissue damage, such as musculoskeletal injuries, are excluded from the general theoretical injury definition above, as these conditions do not immediately exceed the threshold of human tissue tolerance (but rather often result from low energy exposures that can accumulate over time until tolerance is exceeded) 6, it is likely that Orchard et al would wish to include these injuries in an operational definition of a cricket-related injury as musculoskeletal injuries represent a large proportion of reported cricket-related injuries 7,s. In addition, using Orchard et al's injury definition, other medical conditions (for example, an illness such as influenza) would also be included, even though these are not injuries. Indeed, it is unclear whether or not something like stress would be included under their definition. Finally, it is also unclear whether an injury sustained outside the sporting arena, for example from a motor vehicle crash, that prevented the player from being 'fully available for selection' would be included in the Orchard et al definition of injury.

Poorly defined operational definitions of injury are not new to the sports area 9. We would encourage Orchard and colleagues to consider the development and publication of a more specific theoretical definition together with an operational definition of cricket-related injury in order to ensure

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standardisation of a case definition and to contribute towards obtaining high sensitivity and specificity for identification of injuries to cricketers. Otherwise the incidence of cricket-related injury is sure to vary due to different interpretations of what is an injury, making international comparisons difficult.

Furthermore, the currently proposed cricket injury definition appears to be intended for elite cricketers and whether or not this definition could be consistently applied to other levels of the competition (eg, communi ty level) would be of interest.

References 1. Orchard, J., Newman, D., Stretch, R., Frost, W., Mansingh, A., and Leipus, A., Methods ibr injury surveillance in international cricket. Br J Sports Med, 2005. 39(4): e22-e29. 2. Orchard, J., Newman, D., Stretch, R., Frost, W., Mansingh, A., and Leipus, A., Methods for injury surveillance in international cricket. J Sci Med Sport, 2005. 8(1): 1-14. 3. Baker, S., O'Neil, B., Ginsburg, M., and Guohua, L., The lnjuryFact Book. 1992, New York: Oxford University Press. 4. World Health Organisation, ICD-IO IntcrnationM Classification of Diseases, 10th revision. 1992, Geneva: WHO. 5. World Health Organisation, ICD-9 International Classitlcatton o f Diseases, 9th revision. 1977, Geneva: WIIO. 6. Kumar, S., Theories of musculoskeletal injury causation. Ergonomics, 2001.44(1): 17-47. 7. Leafy, T. and White, J., Acute injury incidence in professional country club cricket players (1985-1995). Br J Sports Med, 2000. 34: 145-147. 8. Orchard, J., James, T., Alcott, E., Carter, S., and Farhart, P., Injuries in Australian cricket at first class level 1995/1996 to 2000/2001. Br J Sports Med, 2002(270-275). 9. Finch, C.F., An overview of some definitional issues for sports injury surveillance. Sports Med, 1997. 24{3): p. 157-63.

Rebecca Mitchell and Andrew Hayen NSW Injury Risk Management Research Centre, The University of New South Wales

Rejoinder by authors

We thank Mitchell and Hayen for their criticisms of our consensus definition of cricket injuries. We agree that our "injury" definition is based on maintenance of high level function (ie, ability to continue playing at elite level) rather than physical tissue damage. We accept that this introduces a certain bias into the definition, namely that some players may be able to continue to play with a certain level of physical injury whereas others may need to stop playing with apparently the same physical damage.

An alternate definition based on "physical tissue damage" rather than function would introduce a more problematic bias. The incidence of physical tissue damage in elite cricketers is extremely high 1. Of course, not every physical symptom is investigated, nor is it even necessarily reported to the team injury surveillance recorder. The variation in what might be reported as a cricket injury with a "tissue damage" definition would be enormous and we believe would be far greater than the variations in ability to function under our proposed definition.

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