Injuries in Rugby Union: A Review

Abstract

Rugby Union is one of the most popular team sports in the world. It is a contact sport that emphasizes possession and control of the ball. By virtue of its full contact nature and lack of protective equipment, Rugby Union is associated with a high incidence of injury relative to many other sports. In fact, Rugby Union carries a significantly higher relative risk of injury than American football, with increase differences in the overall rates of injuries. There are multiple distinct phases of Rugby Union: The Scrum, Tackle, Ruck, Maul and Lineout. Each phase of rugby has its own inherent risk and incidence of injuries which include but not limited to concussions, as well as sprains, strains, and fractures of the upper and lower extremity ligament. The majority of injuries occur either during the scrum and tackling phases of the game. The governing body of Rugby Union is constantly adapting the rules to reduce injuries. Some of these rule changes may have unintended consequences. This article will review the current literature and describe the injuries in each phase of rugby as well as discussing concussion and the effect Covid-19 has had on Rugby Union.

1. Introduction

Rugby Union is one of the most popular team sports in the world. It is a contact sport that emphasizes possession and control of the ball. Unlike American football or Rugby League possession of the ball is not necessarily guaranteed after stoppage of play or when the ball carrier is tackled to the ground. It is emphasized with coach and rules to keep the ball in play as much as possible [1, 2].

There are many different forms of the games from touch rugby for the novice players, the seven and ten-man team version, (The seven-man team version is now an Olympic sport), and the classic 15-man version. Each version is based on the same premise that the ball can only be passed backwards, and the goal is for the team to maintain position of the ball and touch the ball down in the try zone. Each version has their own unique incidence of injuries and in this chapter, we will be discussing injuries in the classic 15-man version of Rugby Union [1, 2].

The classic 15-man rugby team (See Figure 1) is made up of eight forwards who are usually large and stronger players. There is one Scrumhalf who calls the plays and distributes the ball to the other players and six back line players who do the majority of running and passing the ball. These seven back line players are usually quicker but not as large as the forwards. Rugby Union has multiple discrete phases of play: The scrum, line out, the ruck, the maul, open play, and the tackle. Each phase of the game has its own unique set of injuries with identifiable risk and incidence [1, 2].

Figure 1.

The 15 players on a Rugby union team (forwards 1–8, scrumhalf 9, backline 10–15).

The forward or pack players include two props and a hooker, two second rows, two flankers, and one eight men. The players get their names from their position in the pack when a scrum is formed. When a minor infraction occurs to reset play many times a scrum is formed between the two teams to restart play. The front row consists of the hooker and two props the hooker wraps his arms around the props shoulder and the props wrap their inside arm around the hooker’s waist holding him (propping) up. Each of the seconds places their head between the hooker and inside arm around the other second rows waist and the outside arm through the legs of the prop and they grab the prop’s jersey. The flankers are in the same level as the second row and wrap arms around the second row’s waist. Finally, the eight man places his head from behind between the second rows. (See Figure 2) [1, 2].

Figure 2.

The two packs of forwards come together to form the scum. Notice how the hooker who is in the front row between the two props arms around them and cannot be used for any mitagation of the forces on engagement of with collapse.

After a minor infraction, the non-penalized team has the opportunity to gain possession and put the ball back into play by rolling the ball in the scrum between the two packs. Each team’s pack is assembled with all eight men coming together. Once together, the props touch their opponents’ shoulders. After this is done the referee instructs the players to engage through specific commands. Their front rows should engage under control, but one team is always trying to gain the upper hand to control the ball and this interaction in some instances can be quite violent and severe injuries can occur. Once the scrum is formed the hooker signals the scrum half. When the scrumhalf puts the ball between the two packs in the scrum, the hooker uses his/her leg (while being helped up by the props) to sweep the ball towards his side. During this time there can be a lot of jockeying for dominance with pushing and pulling of each scrum which can cause the scrum to rotator or collapse which often result in injuries. The hooker can be very vulnerable because he has his arms around the props and nothing to protect him if the scrum collapses. The goal of the scrum is to maintain stability and to get the ball to behind the second rows feet where either the eight man or scrum half can take it out of the scrum and restart play [1, 2].

If a ball goes out play the line out is formed and used to restart play. The line out can be made up of part or the entire scrum. The two teams line up a meter apart. The hooker throws the ball in after a play is called. The hooker must throw the ball straight between the two teams. The team throwing the ball in has the advantage of knowing where the ball is being thrown to facilitate restart of play. The players around the one receiving the ball can lift him to allow him to cleanly catch above the opposing players. The player who catches the ball usually tosses the ball or makes it presentable for the scrumhalf to pick it up and toss it to his back line. (See Figure 3) [1, 2].

Figure 3.

The lineout. The two lines must be 1 meter apart.

The ruck and mauls are similar and occur after a player is tackled to the ground: The ruck or remains standing: The maul. The goal is to make the ball easily accessible to the scrumhalf to keep the ball in play. Rules have been developed to facilitate presentation of the ball to avoid stoppage of play. (See Figure 4) [1, 2].

Figure 4.

The ruck is formed after the tackle and one of more players from each team engage which each other.

When a player is tackled the tackling player must wrap their arms around the opponent with the ball. It is a penalty if he strikes the ball carrier without wrapping his arms. The tackler cannot tackle above the shoulders or upper arms (See Figure 5a). The tackler is responsible for bringing the player to the ground safely. The tackler cannot lift the player up and forcibly drive the ball carrier to the ground. Once tackled and a ruck is formed, the ball carrier must decisively present the ball to be picked up by the scrum half or another available player. If the ball is not presented, then the play is whistled dead, and a scrum is called. The tackler’s teammates must stay on their side of tackled ball player, if not they will be called for an offsides penalty [1, 2].

Figure 5.

a: The player must not be tackle above shoulder level. Recent rule changes have lowered as seen in the figure. b: Proper tackling techniques are vitally important to avoid injuries.

The backline players form a line behind the scrumhalf and the ball is tossed backward to them as they run forwards and gain field advantage. In addition to passing the ball backwards, a team can kick the ball forward. When the ball is kicked forwards and remains in the field of play the person who kicked the ball must run and be in front of all his team plays prior to anyone else touching the ball or engaging the player who caught it. Kicking is an important part of rugby but it does not have any incidence of true injuries so it will not be discussed in this article [1, 2].

Each phase of rugby has its own inherent types and incidence of injuries. Most injuries occur during the scrum and tackling phases of the game. The governing body of Rugby Union are constantly adapting to reduce injuries. Major rule changes have been made to make the scrum safer, avoid excessive energy on engagement and avoiding collapse. Additional rules have been made to ensure the ball carrier is tackled safely and given the opportunity to present the ball to his side of the field [1, 2]. Many American football teams teach Rugby Union tackling techniques to reduce the incidence of injury in their players (see Figure 5b) [3]. This article will review the current literature and discuss the recent rule changes as applicable.

2. Injuries

By virtue of its full contact nature and lack of protective equipment, rugby is associated with a high incidence of injury relative to many other sports. In fact, a prospective study of collegiate rugby and football demonstrated that rugby carries significantly higher relative risk of injury than football, with pronounced differences in the rates of shoulder, wrist, hand, and lower leg injuries overall [4].

There are several injuries that are an inherent risk of any contact/collision sports such as concussion, upper and lower extremity injury including fractures and ligamentous injuries [5, 6]. Over the past several years there have been procedures and policies put into place to attempt to decrease the incidence of injuries. We have observed similar attempts at this in other sports as well as in American football with tackling policies to reduce the risk of cervical spine and spinal cord injury by avoiding direct contact to the top of the head or helmet by either the tackler or ball carrier [7]. There are additional factors that have been associated with an higher incidence of injury they include games in the earlier part of the season, more veteran and professional high-level matches in a season, and decreased rest for the players between matches [8].

3. Tackle

Rugby Union is distinguished from many sports by the manner in which it combines a quick pace of play with an aggressive, full-contact ruleset [9]. The tackle phase of rugby union occurs more often than any other phase. The tackle phase almost always occurs when at least one player is in motion, usually running at full speed. Many systematic reviews found that the majority of rugby injuries come during the tackle phase of play [10, 11, 12]. One study showed that over fifty percent of all rugby union injuries were actually the direct result of tackling or being tackled [10]. Unlike American football, during which players are protected somewhat by a helmet and padding which protects the shoulders, chest, hips, knees, and thighs, rugby players are subjected to several collisions and tackles throughout a match without protective equipment. Studies have shown that the act of tackling, both as the tackler and the tackled, are especially vulnerable for players, as between one third and one half of all rugby injuries occur during the tackle [10, 11, 12]. In general, injuries are more common while performing a tackle rather than getting tackled. The tackler is at a higher risk of injury, especially regarding concussion; however, the player being tackled is also at risk of concussion, ligamentous injury, and fracture. A concussion can be either caused by the head hitting the opponent’s body, especially in high tackles or when the player goes to the ground and the head can strike the turf. Furthermore, where the ball carrier is tackled there is a different risk of injuries. So, when it comes to the tackle phase, it has been studied that far more injuries occur when the ball carrier is tackled on the middle and high position of the torso. Similarly, it was seen that tackles from the front and side of the individual also result in a higher incidence of injury [10].

There have been some discussions about lowering the level of which the ball carrier can be tackled to below the waist [12]. In the open field this should not be difficult since this is how most tackle occurs anyway. It may fundamentally change the game for the forwards, especially plays off the ruck and back of the scrum where many times a forward would handle the ball and there is only a short distance between him and his opponent. The ability and time to react to the ball carrier would be very limited and could make it difficult to make tackle. Furthermore, this would place the tackler’s head nearer to a larger opponent’s knee which may increase the chance of concussions. Concussion may also increase as the force the player hits the turf may also be increased. There also may be an increased incidence in ligament injuries of the knee from possible hyperextension or valgus forces placed in the knees during the tackle below the waist [13, 14]. It is agreed that rules changes are necessary as the governing bodies are doing, they are thoroughly venting these changes prior to implementing [1].

As stated previously present, the tackler must wrap and bring the ball carrier safely to the ground. With the changes in the rules allowing the ball carrier to present the ball to his side instead of immediately releasing it, this has kept the ball in play but may have unintended consequences. The senior author who has been involved in both American Football, Rugby Union and Rugby League has observed an increase in the violence of the collision between the ball carrier and tackler. This is especially when the ball carrier is a larger player such as a forward. He sees similarities between Rugby Union and League in the violence of the collision. In Rugby League the player is tackled and held down by their opponent and play is then restarted. Due to rule changes in Rugby Union now, allowing the ball carrier to have increased opportunity to keep the play going after being tackled, the player can go in with increase force. With players now being larger and faster this may cause an increased incidence of significant injuries in the tackling phase of the game, including concussions.

4. Ruck

The ruck is when players are engaged with one another immediately following a tackle. The ruck is formed when at least one player from each team engages over the ball after an attacking player is tackled and subsequently releases the ball. While the tackle is associated with the highest rates of injuries among rugby players, there is also a significant risk of injury during the ruck. Some of the most common injuries that result during the ruck phase are lower extremity ligamentous injuries as players fall onto the legs of their teammates or opponent. Furthermore, lower extremity injuries are most common because of the dynamic nature of participating in a ruck and being upright and the uneven forces that get placed on the lower extremity muscles [4, 5, 6, 8]. One study highlighted that that gastrocnemius muscle is often one of the muscles injured during the ruck phase of rugby [6].

5. Scrum

The scrum is a part of the game where players from both teams stand side by side surrounding the ball and come together to ultimately fight for possession of the ball. This constituents of eight players from each team’s pack with a total of 16 players involved in the scrum own (See Figure 1). The forwards are usually the larger and stronger players [1, 15].

In one study of English scrums, it was found the 31% of the scums were found to result in injury [16]. As with the tackle, devastating catastrophic injury can occur during the scrum and is highly associated with head and spinal cord injury [16, 17, 18]. Injuries to the players can happen when they engage their shoulders and neck, the unbalanced forces during the scrum can cause severe damage to an individual’s spinal cord if flexed, twisted, or manipulated incorrectly. The scrum can collapse as well, which essentially means the players fold in on one another. The collapsing of the scrum has been shown to have significantly higher rates of injury when compared to scrums that do not collapse. When the scrum collapses, the crown of the head of the props and especially the hooker can strict the ground with significant force resulting in severe cervical spine and or spinal cord injury. The hooker can be especially vulnerable since he cannot protect him or herself when the scrum collapses [16, 17, 18, 19].

While many rule changes in rugby over the past decade have centered around reducing the rate of concussions, it is important to highlight other rule changes that have sought to make rugby safer for athletes. The scrum accounts for 40% of spinal injuries sustained by rugby players. Starting in 2013, the pre-scrum sequence was changed to “Crouch, Bind, Set” following a series of alterations over the previous decades. This “bind” command instructed the “props”, or the forwards directly engaged with the opposing team during the scrum, to lock onto their opponents prior to the ball being played. This leads to a more stable scrum, but also reduces the multidirectional forces experienced by forwards in the scrum, and thus alters the potential for injuries. Cazzola et al. demonstrated reduced biomechanical loading and c-spine acceleration using the current scrum protocol relative to earlier techniques [20]. Furthermore, this rule change is proposed to decrease the frequency of collapse of the scrum, which has been shown to increase risk for injury in the scrum. Further study will be required to see if this change has led to reductions in injuries from the scrum. There have been rules and regulations to make sure each team has enough skilled players to form and maintain a proper scrum. Additional rules have been made to make under 19-year-old rugby scrums safer and prevent inappropriate cervical loading on these individuals [2].

The scrum can take its toll on a player over the years. It has been shown that individuals participating in the scrum are at risk for both acute spinal cord damage and chronic cervical degeneration. When compared to tackling, the scrum occurs less frequently during the game, however, is associated with a higher risk and relative incidence of injury [16, 18].

6. Lineout

The lineout describes a set piece which occurs after the ball or a player carrying the ball goes outside of the touch line. The line-out then consists of a thrower from one team putting the ball back into play by throwing the ball between groups of players from opposing teams who then lift, or “support” one teammate who goes straight up to receive the thrown ball. This play is associated with lower rates of injuries compared to other phases of play; however, it is often associated with more serious injuries, with one study reporting that 80% of players injured in a line-out were removed from play, which is much higher than other phases of play [9]. Players jumping for the ball are lifted several feet into the air and may be destabilized as they reach for the ball and/or collide with other players. Injuries sustained in lineouts include incarcerated inguinal hernias, ligamentous injuries such as ACL (Anterior Cruciate Ligament) tears, and lumbar and cervical facet injuries [6, 8]. The vulnerable positions created for players, especially those jumping for the ball, has led to restrictions on lineouts for youth rugby players. Typically, full contested lineouts are absent from the game until the U16 level for boys, and U18 for girls. This protects young athletes from the potentially disastrous consequences of lineouts in competitive play [2].

7. Concussion

Concussion is associated with nearly all phases of play during a rugby match or training session. Perhaps not surprisingly, the rate of concussion among rugby players is higher than many other sports with available concussion data. In fact, the rates of concussion are like those seen in boxing. This is primarily due to the intense contact nature of both sports. One literature review looked at the incidence of concussion injury and stratified them specifically by sport. Specifically, concussions accounted for 15% of all injuries experienced by rugby players. This can be further represented when looking at concussion rate per athletic exposure (AE). One systematic review showed the incidence of concussions in match play rugby were a staggering 3/1000 (AE) [13]. This rate is much higher than many other team sports. When comparing American football to collegiate rugby the incidence of injuries is more in rugby. These injuries specifically are concussion and upper extremity ligamentous sprain and strain. Over the past ten to fifteen years, more attention has been brought to the impact of concussions on the game of American football as more is understood about the short- and long-term effects of concussion as well as the additive effects of multiple concussions.

Many concussions that occur in rugby may go underreported as individuals do not want to sit out of play. It has been shown across the board that rugby players actively choose to avoid reporting concussive episodes [21, 22, 23]. Analysis of elite level rugby competition have demonstrated that there are a few factors which increase the risk of concussion during a tackle. These factors included acceleration by the tackler into the tackle, high rate of speed of the tackler at time of collision, head-to-head contact, and high tackles. These studies highlighted some of the major challenges in reducing concussions through rule changes implemented in the tackling phase of play [9, 10, 11, 12]. For instance, the most obvious rule change that would likely decrease the incidence of concussions in rugby would be to eliminate tackles from the game altogether; however, this change would not be well-received as it would completely change the nature of the game.

Other rule or strategy changes may be more feasible but would have less predictable outcomes on concussion rates. One example of this would be to reduce the amount of space between lines of players on set pieces to reduce the speed of tacklers on these plays. A possible unintended consequence would be that players would likely accelerate into the tackle more frequently given less space to make a play and as stated previously increase ability to keep the ball in play. While increasing enforcement on high tackles and head-to-head contact, the latter of which is already treated with a zero-tolerance policy by World Rugby, may reduce the incidence of these specific types of contact, they may increase the rates of lower tackles and head-to-knee contact, which has also been shown to increase concussion risk.

Over the past several years, there have been many efforts to reduce the rates of concussions in American football competition, including rule changes aimed at reducing head-on collisions involving defenseless players [7]. Perhaps even more important to protecting players have been the advances in reporting and return-to-play protocol. While it is not clear to what extent that the game of rugby has been directly affected by the literature and cultural shifts regarding concussions in American football, there have been changes to the way in which concussions are reported in high-level rugby competition, as well as rule changes aimed to protect players from sequelae of these injuries [1, 2]. Most recently, in June of 2022, World Rugby implemented new changes that lengthened the amount of time players must wait before returning to play after suffering a concussion from seven to twelve days. This change was promoted by the World Rugby independent concussion work group 17-Strong. This rule change will have a large impact on how concussions affect competitive gameplay, as it will in many instances delay players from returning to the subsequent week’s competitive play [1].

8. COVID-19

Due to the physical nature of rugby and the proximity of players during various phases of play, additional safety concerns were introduced to the game of rugby during the SARS CoV2 epidemic. Since perhaps the source of the greatest prolonged physical contact comes during the scrum in a rugby match, some leagues reduced or even eliminated the scrum from gameplay during the 2020 season. It is unclear if this measure had any impact on the reduction of Covid 19 transmissions during professional or amateur rugby matches [24, 25]. Furthermore, Jones et al. showed that the risk of transmission of SARS CoV2 was lower than initially predicted, and that in-game transmission could not be confirmed in their study population [26].

9. Summary

Overall, rugby is a physically demanding sport that predisposes individuals to severe injury on occasion. There are several distinct phases of rugby that injury can occur in. It is important to evaluate an individuals’ injury in the context of what phase of rugby that the injury occurred in as this can lead to further understanding of the ideology and mechanism of the stated injury. The scrum, ruck and tackling phase of rugby all come with their inherent risks. In the future it would be important to analyze the regulations and rules to utterly understand how to mitigate risk of injury and if rule changes have unintended consequences. Additionally, it is important to maximize players position skill and tackling before entering match play as well as. As with any field sport that requires significant cardiac fitness, optimizing recovery in between matches to ultimately decrease the incidence of injury are important as well. Multiple studies have shown an increase in injuries with fatigue [6, 8].