Listeners to More or Less on BBC Radio 4 have asked where I got the data to make the points that
- rugby players up to the age of 18 or 19 had a 28% chance of getting injured over a season of 15 matches (ie, with a million children playing every year with this risk of injury there could be at 300,000 extra injuries a year, including up to 100,000 concussions)
- 90% of injuries resulted in more than seven days lost from school
Probability of injury in a season ranges from 12% to 90% depending on study characteristics including injury definitions used (see table 3, page 92 of Allyson Pollock, Tackling rugby: what every parent should know about injuries Verso 2014).
A more recent systematic review (with more studies) showed probability of a player being injured in a season ranged from 6% to 90% with 28% risk of injuries (pooled-incidence estimate) regardless of need for medical attention in a season (Andreas Freitag et al. Systematic review of rugby injuries in children and adolescents under 21 years British Journal of Sports Medicine 2015).
The Ulster study of schoolboys showed that of the 825 boys playing in a season, there were 426 injuries, and a player had a 36.8% risk of injury (the number of children experiencing one or more injuries in a season was 304 or 36.8%) (HAP Archbold et al. RISUS study: Rugby injury surveillance in Ulster schools British Journal of Sports Medicine 2015).
I have applied these probabilities to the RFU projections of targeting rugby in 750 state schools and one million children – the lowest estimate of injuries is 100,000 (based on the lowest probability of 12% in the book). Using the 28% figure in the systematic review gives 280,000 which has been rounded up to 300,000, but of course the number of injuries could be much much higher.
Concussion. Data in the Ulster study show concussion accounted for one in five of all injuries. Our systematic review showed 0.3% to 11.4% risk of concussion injury in a season (Graham Kirkwood et al. Concussion in youth rugby union and rugby league: a systematic review British Journal of Sports Medicine 2014).
The largest prospective study available estimates a probability of 11.4% of child or adolescent rugby union players sustaining concussion over a season, equivalent to between one and two players in every school or club youth rugby team sustaining a concussion every season on average. Applying the 11.4% figure to the one million children gives up to 110,000 concussions, or 100,000 rounded down.
Time loss. A key finding of the Ulster study was the high proportion of severe injuries. It showed that approximately 90% of injuries resulted in at least seven days of time loss. Indeed, the total time loss to injury was 18,091 days, with an average of 646 player days lost per school, per season. This is equivalent to 92 weeks of time loss, or each school losing approximately four players for an entire season. Approximately, half of all injuries resulted in more than 28 days’ time loss; with the majority due to fractures of hand/finger/thumb, sprains to the ankle or knee, sprains or dislocations of the shoulder, or concussion. Fractures and dislocations were the most severe injuries in terms of requirement for surgical intervention and extensive time lost from participation, which is consistent with previous reports. A key concern is that time loss injuries may also necessitate extended school absence and have greatest potential for long-term morbidity; however, this was not measured in the present study.