The importance of injury and training data in professional rugby union

The high incidence of injury in professional sport is obviously detrimental to an individual’s short and long-term health and also the team performance. The incidence of injury in contact sports, such as rugby union, is particularly high compared with non-contact sports. In elite rugby union, it appears to have increased since the introduction of professionalism in 1995. A comparison of the injury rates in Australian international rugby union pre- and post-professionalism shows a rise of 57% (Bathgate et al., 2002), while the injury rate in professional players in Scotland was nearly twice that for amateur players in 1997-1998 (Garraway et al., 2000). Possible causes for this rise include a greater match intensity at the professional level that creates more frequent and more powerful player impacts; a higher number of elite matches; a short off-season (particularly in the northern hemisphere) leaving little time for recovery and pre-season preparation; excessive pre-match training leading to player fatigue; or musculoskeletal weaknesses. However, none of these risk factors has been quantified or objectively assessed in rugby union.

Common solutions

A sufficient number of qualified experienced and competent medical staff are required to deal with the number of injuries arising in rugby union. However, a more efficient strategy is to prevent injuries occurring in the first place. Musculoskeletal screening and the prescription of specific training exercises to alleviate physical deficiencies in players may reduce the risk of injury; however, research on injury risk factors is often limited to amateur participants and is rarely specific to rugby union (Murphy et al., 2003). Other methods of prevention include the implementation of a general programme of injury prevention or prehabilitation in an attempt to reduce the risk of injuries; the regular assessment of player fatigue to mediate overtraining; and adherence to regular recovery and relaxation strategies.

Using evidence-based prevention strategies

Owing to the lack of specific and objective knowledge of the incidence, prevalence and risk factors for rugby union injuries, prevention strategies are often based on perceptions rather than evidence. Injury and training data from a large cohort would provide valuable information for medical and conditioning teams from which to develop injury prevention and treatment strategies. This type of data is essential because professional sports clubs have a legal obligation and a duty of care responsibility to their players to document and implement suitable management strategies to minimise injury risks (Fuller, 1995).

Epidemiological considerations

The incidence of injury varies widely within and between sports, due in part to inconsistent methodologies. Recording injury and training profiles is only of real benefit if appropriate consideration is given to the methodology and the means of data analysis and interpretation. It is also necessary to have an adequate cohort size and number of injuries to provide significant results.

Injury definition

The contentious issue of injury definition dominates discussions about sports injury epidemiology. Definitions include injuries resulting in an insurance claim, hospital treatment, time lost from sporting participation and assessment by the team physician; consequently inter-study comparisons are often difficult. Although a standard injury definition for all sports and all levels of participation would improve comparability, it may be unsuitable for individual sports populations. For example, a single definition based on absence from competition and training may not be appropriate for both amateur and professional cohorts, as the incidence of injury may be affected by the frequency of training and competition. It is necessary, therefore, to ensure that the definition is appropriate for the population studied and the surveillance objectives of each epidemiological study, and where comparisons are made between sports and groups that the definitions are compatible.

Exposure data

Collecting players’ exposures to training and competition, during which there is an opportunity to sustain an injury, is essential to determine the incidence of an injury (commonly reported as injuries per 1000 hrs). This figure can then be compared with other studies, players, seasons and teams; all of whom may have different exposure to training and competition. Furthermore, the influence of exposure time per se on injury incidence cannot be assessed. In a recent football study (Woods et al. 2002), it was highlighted that a greater proportion of injuries occurred during the pre-season period than at other times of the season; however, because the volume of training may be greater during the pre-season period the risk may be no greater, or even less (per 1000 training hours) than during training at any other point during the season.

Another benefit of collecting exposure data for players is to assess the impact of intrinsic and extrinsic risk factors on injury. Failure to gather exposure data would limit the analysis to just reporting proportions of injuries, and this could not be used to assess risk factors. The link between training practices and injuries also requires the measurement of individual training volumes.

Risk-based injury assessment

Acknowledging an injury episode and reporting injury incidence without recording its severity provides a limited assessment of a player or team’s injury profile and this may fail to highlight injuries of the greatest concern. For example, if over a season, a rugby team sustains 20 quadriceps haematomas, while only sustaining five lateral ankle sprains, the incidence of quadriceps haematomas is four times higher per 1000 hours of playing and training. However, the haematomas may, on average, keep players out of training and playing for three days per injury, while the lateral ankle sprains may take 14 days on average to be resolved. Therefore the total risk to the team from ankle lateral sprains is 70 days, while for quadriceps haematomas it is only 60 days.

A risk-based assessment that takes into account the severity of injuries is preferable when identifying the most prevalent injuries. Sporting time lost from playing and training is probably the most important determinant of severity in professional sport, due to the performance and cost implications to all stakeholders. This information identifies the most prevalent injuries instead of relying on reports of injury incidence (van Mechelen, 1997), and it forms an important part of risk-based assessments (Drawer and Fuller, 2002). For example, in English professional football the greatest proportion of injuries occurred to the thigh; however, using risk-based analysis it becomes apparent that knee injuries cause the greatest proportion of training/playing time missed (Drawer and Fuller, 2002).

Benefits of accurate injury and training data collection

In the short-term, collection of injury epidemiological data allows the incidence of injury to be compared with previous seasons, teams and studies. Incidence allows injuries or mechanisms of injuries causing the greatest concern to drive prevention strategies. In reality, many sports injuries have multifactorial risk factors. An effective surveillance system for elite professional rugby union should, therefore, provide detailed epidemiology of injuries and allow the identification of intrinsic and extrinsic risk factors for these injuries. Consequently, individual players or populations of players at high risk of a specific injury can be identified, and their training and/or match behaviour modified. While the collection of data must remain broadly based to generate a large volume of homogeneous data to be gathered, it is of benefit to shift the focus of collection towards areas of most concern or ambiguity.

Injury analysis and prevention in the future

It will never be possible to prevent all injuries in a powerful contact sport such as rugby union. However, sufficient investment in medical and conditioning expertise and facilities may be critical in reducing the incidence and prevalence of injury in the game. Regular and detailed analysis of individual player’s musculoskeletal systems, training practices and medical and training histories to assess potential risk factors, followed by appropriate modification of training programmes, should be encouraged. Although such practices may appear to be expensive in the short-term, they may prove cost-effective in the long-term.

Future analysis of injuries, training and risk factors in rugby union should be focused on the individual dynamics of sporting exposure and the individual screening of players for intrinsic risk factors. The availability of computerised match analysis systems, recording the exposure to different movement patterns performed during a match, would greatly aid the analysis of injury data. Further information on injuries may also be gained from video analysis of the injury episode during a match. Research on intrinsic risk factors is rarely specific to professional rugby and the general analysis of musculoskeletal risk factors over a period of time may further help to eliminate injuries from the sport of rugby union.

John Brooks

References

Bathgate, A., Best, J.P., Craig, G., Jamieson, M., and Wiley, J.P. (2002) A prospective study of injuries to elite Australian rugby union players Br. J. Sports Med., 36: 265 - 269.
Drawer, S. and Fuller, C.W. (2002). Evaluating the level of injury in English professional football using a risk based assessment process Br. J. Sports Med., 36: 446 - 451.
Fuller, C. W. (1995) Implications of health and safety legislation for the professional sportsperson Br. J. Sports Med., 29: 5-9.
Garraway, A.J., Lee, A.J., Hutton, S.J., Russell, E.B.A.W. and Macleod, D.A.D. (2000). Impact of professionalism on injuries in rugby union Br. J. Sports Med., 34: 348-351.
Murphy, D. F., Connolly, D. A. J. and Beynnon B. D. (2003). Risk factors for lower extremity injury: a review of the literature Br. J. Sports Med., 37: 13 - 29.
van Mechelen, W. (1997). The Severity of Sports Injuries Sports Medicine 24(3): 176 - 180.
Woods, C., Hawkins, R., Hulse, M., Hodson, A., Andersen, T.E. and Bahr R. (2002). The Football Association Medical Research Programme: an audit of injuries in professional football – analysis of preseason injuries Br. J. Sports Med., 36: 436 - 441.