Injuries in Rugby : an overview & analysis of the latest datas

What are the most common injuries ? When do they occur ? Who is most prone to injury ? How do we get injured most often ? Which sites are most affected ? What are the factors to consider ?

The subject of injuries in rugby union brings up a multitude of questions for both the staff and the athlete. Current rugby is often described as increasingly “violent” or “traumatic”. These general and, therefore, not necessarily accurate statements are based on the evolution of the sport since its creation and the constraints that result from it. Injuries have also changed both in number and type. The aim of this article is to define “how” Rugby union has become more demanding and to draw up the spectrum of the appearance of the corresponding injuries.

Of course, it is important to note that the figures presented are not exhaustive as they always belong to a specific context and should rather be interpreted as “trends”. In addition, for the sake of readability, some figures will not be presented. You can find them in “the little guide of injuries statistics” which is a summary with all the detailed values and datas of the concepts presented below. It is only available in French but you can order a english version by e-mail.

Evolution of constraints

Since its professionnalisation in 1995, rugby union has seen a significant increase in the physical and physiological constraints for players. Although the values are different depending on the level, this trend extends from the international to the amateur level. It is logical to ask how these developments have changed the characteristics of injuries.

Fig.1. Evolution of “ball in play” for each RWC.

This graph shows a clear increase in effective playing time (or Ball in play: BIP) since 1995 with a difference of almost 10 minutes between 1995 and 2019. This result suggests that players spend more time in action and less in recovery. The result is an increase in physiological stress.

Fig.2. Number of tackles and rucks per team at RWCs

Meanwhile, there has also been a significant, almost linear increase in the number of fight actions. Between 2003 and 2019, the difference is +34% for tackles and +21% for rucks. We can therefore see that the number of collisions has undeniably increased, leading to a higher metabolic strain for players.

Fig.3.a. Number of possession per match at RWCs
Fig.3.b. Number of phases per possession per match at RWC.

In order to analyse this data properly, the two curves must be read in parallel. On the one hand, it can be seen that the average number of possessions per match has decreased significantly (-29.6 possessions/match) since 1995. On the other hand, the average number of phase (or game time) per possession has increased significantly (+76.4%). These two trends added to the increasing BIP show that the average length of the sequences has undoubtedly increased, requiring the player to make prolonged high-intensity efforts involving fighting and running, thus increasing player exposure.

What should be remembered :

• An increasing “ball in play”
• A greater number of collisions
• Longer and longer sequences (fewer sequences, but with more game phases)

The athlete is now confronted with more time in action with a greater task sequence constraint. This, firstly increases, the “statistical” risk of injury. Of course, the higher the effective playing time, the more players are exposed to the risk of injury. Secondly, the ability to repeat high-intensity actions imposed by longer sequences leads the rugby player to perform actions in a state of considerable fatigue which results in a degradation of the technical execution. It has been shown that this “technical” dimension has an important relationship with the onset of injuries, particularly at the level of concussions for the tackle technique for example. This decrease in efficiency induces bad behaviour, inappropriate postures and uncontrolled intensities that increase the risk of incident.

The evolution of the game and the physical demands of the rugby player is therefore an important factor in the evolution of injuries. However, injuries are due to a convergence of parameters and therefore depend on a multitude of factors as we shall see below.

Evolution of injuries

Injuries in numbers

Among the large number of figures presented in the multitude of studies that deal with this subject, those that frequently emerge fall into two categories : Game vs. Training. The data mentioned are generally expressed in number of cases per 1000 hours of practice.

In games :

Fig.4. Number of injuries/ 1000 hours of match time according to the season.
Fig.5. Number of days of absence per injury as a function of the season.
Fig.6. Number of days of absence/1000 match hours per season.

From these three curves it can be seen that the total number of injuries has not increased significantly since 2003. However, the severity (number of days of absence per injury) shows an almost linear increase. A similar amplification is observed for the number of days of absence/1000h of games. These 3 results mean that even if the number of injuries has not necessarily increased, today they are much more severe and lead to longer recovery periods.

In the analyses of multiple seasons, the average number of injuries is calculated to be around 100 to 110 injuries/1000h of match time, representing an injury risk of ±10% per match depending on the studies. In addition, the average duration of absence per injury (or severity) is estimated to be 40 days of absence/injury in competition. Finally, if we combine these two parameters, we obtain a duration of absence of 3401 days/1000 hours of matches.

In training :
Compared to the figures corresponding to the competitive context, the number of injuries is significantly lower in training situations. The number is 3 injuries/1000 hours of training, which means more clearly that for a training group of 40 players, there is an average risk of 3 injuries every 25 hours of training. At the same time the severity of the injuries is 37 days of absence / training injury, and the average load is 106 days of absence / 1000 hours of training.

How do injuries occur ?

This is an interesting question to ask, even if we can conjecture that the fighting phases would be more likely to cause injuries than other actions in a rugby match, less information is available on this subject.

Fig.7. Percentage of match injuries as a function of the event

It is observed that tackling is the action most likely to lead to injury, whether by tackling or being tackled, and accounts for almost 50% of accidents. We can also observe that the number of tackling injuries has increased significantly in the 2017-2018 season compared to the averages for the 2002-2017 seasons.

Which kind of injury is the most frequent? 

Knowing the types of injuries that occur most often and their degree of severity allows us to have a good idea of the constraints and to anticipate risk areas among athletes.

Fig.8. Number of injuries and number of missed matches by type

Ligament damage is the most common, followed by fracture. These two categories are also the ones that result in the most missed games for players. Finally, concussions play an important role.

These results can be explained in part by the significant increase in the number of concussions since 2002.

Fig.9. Number of concussions per 1,000 hours of match time by season

The explicit dynamics of this curve can be qualified by the fact that concussions were not the subject of great vigilance until recently. Only “visible” concussions, which represent a minority proportion of all concussions, were recorded.

Which sites are most affected? 

After analysing the most common type of injury, it is important to know which anatomical part of the body are most “at risk” in rugby.

Fig.10. Number of injuries and number of missed matches per site.

Among these sites, the shoulder, ankle and knee are the three most affected, with a significantly higher number of missed games. However, we note that the hamstring and the hand are anatomical sites with a low number of incidents for high recovery times.

Fig.11. Percentage of injury by site

This graph from another study shows slightly different results, particularly in the head area, as it includes concussions, unlike the previous graph. On the other hand, we find higher percentages for ankle, knee and shoulder injuries. Finally, we can see that muscular injuries of the lower limb also occupy a large share of this graph because it includes quadriceps and hamstrings.

Fig.12. Ranking of the five most frequent injuries for each season from 2012 to 2018 as a function of the associated incident ratio (number of incidents/1000h of match time)
Fig.13. Ranking of the five most heavily burdened injuries for each season from 2012 to 2018 according to the number of days of absence (number of days of absence/1000 match hours).

In this spectrum of the most frequent injuries, knees and ankles occupy an important place.

Indeed, rugby, like any “pivot” sport, brings into the game multidirectional constraints on the segments and tissues with often a high level of speed or intensity. This creates torsion between the different joint stages which disrupts the stability of the body structure. If we take the most traumatic action: being tackled (see above), when we are tackled by two opponents simultaneously, our body receives two forces of different intensity and direction applied at two distinct levels (to the leg and trunk for example). Added to the speed and posture of the ball carrier, we can imagine the impact of these stresses on the stability of the structure. Consequently, these pressures require a very fast and very strong motor readjustment in the attacker, which can lead to an ankle or knee injury.

For lower limb muscular injuries, the causes are similar, prolonged exposure to high speeds, impacts and forced amplitude postures imposed by contact often lead to muscular lesions on the lower limbs.

About the shoulder, the figures showing that this joint stage is very frequently affected are consistent with the increase in collisions and in particular in the number of tackles. Indeed, on this action in particular, the shoulder joint is the main area of contact for catching the opponent. The shoulder is therefore considerably exposed on this action, but injuries are also found on falls when the player lay on the ground.

Concussions, on the other hand, can result from several factors. Firstly, the internal logic of rugby where one must move towards the opponent’s camp under all circumstances imposes a forward tilted posture (which allows a better orientation of force in the horizontal modality) to push back or accelerate. This behaviour (head forward) particularly exposes the head to direct shocks on actions carried out with great intensity. The technical component plays an important role (a good placement of the head during the tackle, for example) in preventing this incident, but does not always prevent it. Furthermore, concussions can be caused by an intense acceleration (or deceleration) of the head. Indeed, it has been proven that a lack of strength in the cervical area leads to insufficient “blocking”. This lack of stability can, for some actions, lead to a concussion without direct shock to the head.
To illustrate this, let’s take a player going to percussion. The latter will launch himself into a pushing posture (trunk tilted) as quickly as possible on his opponent, at the moment of contact, his gravity center is stopped sharply and suddenly goes from a given speed to zero (or even negative in case of a positive opponent’s tackle). During this intense deceleration (at least 3 m.s2 ) there will be a proximo-distal propagation of the shock. If the player lacks of strength to stabilise his head, then the head will move in a direction and intensity relative to the shock out of phase with the centre of mass. In this case, the brain hits the skull, causing the concussion.

Description : Oakville Chiropractor: Concussion Treatment Acupuncture
Movement of the head during contact in case of insufficient locking


Which positions are most at risk?  

The differences in rugby XV activity profiles depending on the position are well known today. However, it seems important to know to what extent these differences between positions can influence the risk of injury.

Fig.14. Number of incident/1000 hours of match time according to the playing position

According to this graph, we can see that the front lines and more particularly the heelers are the most affected positions in the front, while the hinges (9 and 10) are the exposed positions in the back. These results are partly explained by the fact that the pillars and heelers are particularly concerned by combat tasks of all kinds (tackle, ruck, maul, shuffle…). The hinges, as for them, have a big activity. They are the ones that touch the ball the most and are, therefore, very exposed to opponent contacts. All the more so as their fundamental role in the strategy and direction of the game makes them particularly targeted by opponents.

Are there differences according to age?

Compared to the injury data for senior players exposed in the first half, the youngsters seem to be less impacted with 31.4 injuries/ 1000 hours of match time for the youngsters.

Differences according to the level
 
Naturally, it is thought that there are differences between the different levels of injury. With the idea that professionals would be more exposed than the amateur and hopeful levels. These hypotheses are not systematically verified. With 134 to 701 / 1000h game for amateurs, 115 to 825 / 1000h game for semi-pros and 58 to 200 / 1000h game for pros. These figures, taken from an initial study, show that, despite the greater constraints, the more precise monitoring of pro rugby players would seem to limit the number of injuries.

In a second study, it was found that the pros and the hopefuls recorded the same number of injuries, however the injuries of the pros were more severe with a higher number of missed matches than the U23. Training is always lower than other contexts in terms of the number and severity of injuries.

Fig.15. Number of injuries and missed matches as a function of level of play.

Thanks to these data it can be seen that professionals do not systematically have a higher number of injuries than lower levels, probably due to better medical follow-up and more physical preparation. However, they seem to be exposed to more severe injuries resulting in many days of convalescence.

When do they appear ?

This is an exciting and quite topical issue. Does the number of injuries and/or their severity vary during a sports season? Today, certain phenomena seem to be repeated with periods that would be more affected than others.

In games :

Fig.16. Number of injuries/ 1000 match hours as a function of the month.

According to this histogram, we can identify 4 periods of 2 different intensities. September and April are the months with the highest average number of incidents, followed by December and February. At present, we can only be descriptive about these phenomena because despite some hypotheses (sequence of games, sudden difference between chronic and acute load in certain periods, climatic conditions …) none is today clearly retained and validated.

At training:

Fig.17. Number of injuries/ 1000 hours of training as a function of the month.

In the case of training, the months with the highest number of injuries (June, July, August, February and May) are also the months in which the players have a higher training load.

Moreover, in addition to knowing the periods at risk in a sports season, practitioners and especially coaches question the players’ sequencing abilities. Although each player has an individualized ability to play consecutive games without injury, there is a statistical threshold value after which the risk of an incident becomes higher and higher.

Players who experienced low (<15) or unusually high (>35) exposure during 12 months of match play have a significantly different risk of injury (higher for those who played more games).

Fig.18. Linear relationship between injury risks and number of game played monthly with a 90% confidence interval.

From this line we can see that exposure to monthly matches is linearly and positively associated with the risk of injury. Moreover, we can see that after 4 consecutive games, the risk of injury increases significantly and goes out of the neutral risk zone (shaded area on the graph). These results mean that coaches should rotate the compositions in order to avoid overexposing their players to the risk of injury.
If you want to know the exact values for all the games developed above, don’t forget to download the “the little guide of injuries statistics”. There you will find all tables and figures in their entirety. The english version is not available on the website, but feel free to contact us to order it !

Role of the Strength and Conditioning coach

With all this data, fitness and injury prevention professionals have a key role to play in limiting incidents among players.

The S&C coach must take into account as many factors as possible that influence the occurrence of injuries in Rugby union. They can be broken down into 2 parts: factors intrinsic internal to the player (example: injury history, age, functional weakness…) and extrinsic external to the player (example: field surface, climatic conditions, training programme…). There are a multitude of these factors, all of which can have an influence on the emergence of an incident.

We know that an injury is the result of a complex addition of a multitude of factors, as scientists we try to simplify the models and prioritize the parameters, but we also know that a major factor does not systematically have a major impact and that a minor factor, associated with other markers, can have a major influence on the phenomena that occur.  Among these intrinsic and extrinsic parameters, the professional must identify those that are modifiable and those that are not in order to adjust his action, either to prevent an injury from occurring (primary prevention) or to prevent it from reoccurring (secondary prevention).

These factors are very numerous and will be the subject of a more detailed analysis in a future article (example: impact of the surface of the ground on injuries…)


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