Match injuries in amateur Rugby Union: a prospective cohort study
Amateur RU players report similar pre-season health-related quality of life characteristics as the general population. During the competitive season, the match injury rate for amateur rugby players was 52.3 /1000 match-hours exposure, with the head location, ligament tissue type, and tackling mechanism being the most common. Approximately one-third of injuries resulted in 1 week of time-loss from play. Factors associated with higher injury rates in this study were fewer years of playing, lower BMI and lower mental health, but the relationships were weak.
The study used standardised injury definition and data collection procedures, which allows for comparison of our findings with similar studies. We were also able to maintain an individual player exposure log for a more accurate estimate of exposure adjusted injury rate, which is a common limitation of larger (multiple-club observations) studies conducted over several seasons. Due to logistical constraints our study’s hypothesis was explored with a cohort recruited from one amateur rugby club, followed over one-season and this limited sample size may have affected the precision of our estimates and the generalisability of our findings. Hence we likely identify moderate to strong associations. The notion that aspects of HRQoL may be associated with in-season sports injury is novel and adds to previous knowledge on the aetiology of sports injury in rugby.
To the best of our knowledge this is this first time multiple dimensions of HRQoL have been evaluated in a cohort of amateur rugby players. On average both physical and mental component summary scores were similar in this cohort of amateur rugby players when compared to age-matched Australian males. There were however some small divergences below the population norm score in the health dimensions of bodily pain and general health perception. Presumably these lower average scores in bodily pain and general health are linked to rugby related behaviours, such as physical contact in preseason training. Details about preseason injury status were not measured in this study, which limits us to speculation. Dimensions of health could also change with volume and type of rugby participation; consequently the temporal relationship between health, rugby exposure and injuries is an area for future research.
In this study, as expected, the overall match injury rate fell well below the high match injury rate of men’s international and level-1-club professional rugby (52.3 vs. 81.0 per 1000 match hours) [17]. However, the match injury rate in our cohort of amateur players was higher than level 2 professional rugby players (in Hong Kong and Japan) and a recent English cohort study of community rugby players (52.3 vs. 16.5–35.0 per 1000 match hours) [17, 26]. Also unexpected was the relatively low severity of injuries seen in this study (mean days of missed play 9 days); only around 16 % of injuries required more than one-month time loss from play. Results from a comparable study of community rugby players [26] report an average of 7.6 weeks missed per injury for all levels. The high proportion of slight injuries observed in our study may reflect a different risk profile in this cohort (i.e., a higher propensity for slight-mild injuries) or a greater sensitivity in our injury reporting.
Our description of match injuries was also similar to that seen in Scottish and English community rugby players in terms of location, mechanism, phase of play, player position and time of season [26, 27]. A point of difference from Roberts et al., [26] was that we found no difference in the rate of injury based on the time of the match or the grade of play. They, on the other hand, found injury incidence was lower in the first and second match quarters compared to the fourth and higher incidence in higher levels of competition. However, they observed a much larger sample and compared groups of clubs that play across wider levels of competitiveness, which likely accounts for the differences in injury rates across levels of play.
Previous studies have also measured rugby players’ height and mass preseason to assess the relationship between BMI and injury incidence [10, 11]. These studies suggested that players with BMIs higher than 25 kg/m2 are at greater risk of incurring an injury compared to players with BMIs less than 23 kg/m2, though these findings were not statistically significant. We observed the opposite finding, that is, players with higher BMIs were less likely to incur an injury; however, this finding was only significant when BMI was included as a continuous variable in a multivariate analysis. Similarly, player experience (the number of years of rugby participation) has been previously been evaluated as a predictive factor for injury occurrence in cohort studies [10, 11], but not found associated with injury rate. Unlike previous studies we did not categorise player experience and BMI in our model to avoid the known problems of loss of power and less precise estimation [28]. While our adjusted associations were significant the magnitude was small. At this time we believe inferences about the effects of BMI and experience on injury rate should be approached with caution, requiring further exploration in future research.
A simple yet commonly overlooked question in aetiological rugby studies is the impact of HRQoL of athletes on sport-related injury. The hypothesis for the current study follows work of Quarrie et al., [11] who, to the best of our knowledge, are the only group to have evaluated the potential role of a player’s preseason health and psychological wellbeing on injury. To provide a more comprehensive evaluation of rugby player’s overall health, HRQoL was measured with a robust measure that has been used with athletes [29, 30] and validated in patient populations [31]. A novel finding from our study was lower mental domain summary scores had a small association with higher rates of injury when controlling for other variables. Previous studies have found that rugby players who were injured in the previous season [12] or preseason [11] were more likely to be injured during the study season. It may be the case that previous injury adversely affects aspects of HRQoL such as physical functioning [29, 30]. Our model was established a priori with only a few potential predictors. A limitation of our study is that unaccounted for potential confounders such as previous injury may have distorted the prediction of HRQoL on injury incidence. Therefore further research is required to further evaluate the relationship between health and sports injury. Associations between health and rugby injury should be approached with caution at this time.