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Injury-prevention priorities according to playing position in professional rugby union players
  1. J H M Brooks,
  2. S P T Kemp
  1. Rugby Football Union, Twickenham, UK
  1. Correspondence to Dr J H M Brooks, Rugby Football Union, Rugby House, Rugby Road, Twickenham TW1 1DS, UK; johnbrooks{at}rfu.com

Abstract

Objective To examine the match injury profile of professional rugby union players by individual playing position.

Design 4-season prospective cohort design.

Setting 14 English Premiership clubs.

Participants 899 professional players.

Main outcome measure Incidence of match injury (recorded as the number of injuries/1000 player-hours of match exposure), severity of injury (recorded as the number of days of absence) and days of absence due to injury per 1000 player-hours of match exposure.

Assessment of risk factors Injury diagnosis and individual playing position during a match.

Results 2484 injuries were reported. While there were no significant differences in the total days of absence as a result of injury between different positions in the forwards and the backs, there were a number of significant differences in injury profile for players in individual playing positions. Although three common body locations caused a high proportion of days of absence due to match injury for forwards (shoulder, knee, ankle/heel) and backs (shoulder, hamstring, knee), there were significant differences in injury profile between individual positions.

Conclusions The results clearly demonstrate the need for individual position-specific injury-prevention programmes in rugby union. When devising such programmes, a player's previous injury history should also be taken into account.

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Introduction

The incidence of injury in professional rugby union is high in comparison with many other sports;1 furthermore, the total absence from playing and training due to these injuries is also high.1 Reducing this injury burden should be a central focus for rugby union medical, coaching and conditioning teams; however, time and training constraints2 typically limit the scope of injury-prevention interventions. To counter this, it is important to focus on injury-prevention programmes that are most likely to have the greatest impact on reducing the injuries that cause the most days of absence.3 4

Playing position is an easily identifiable, albeit non-modifiable, risk factor that can be used to shape injury-prevention programmes based on differences in injury profile by position. Casual observations as far back as the early 20th century highlighted positional differences in injury profiles.5 These were confirmed in subsequent publications,6,,8 although there was no statistical analysis of the results, and the number of injuries reported in these studies was relatively small. Law modifications and the introduction of professionalism have significantly changed the nature of the modern game of rugby union,9 making these studies less applicable. More recently, studies of injuries to individual body parts in professional rugby union have suggested some positional differences in injury risk.10,,15 However, to optimise statistical power, these studies have commonly grouped positions together, such as the front-row forwards, even though it is recognised that individual positions within these positional groups have subtly different playing roles, are likely to experience different loads and forces through different parts of their bodies during a match and, as a result, may exhibit different injury profiles. An example of a variation in load is the difference in the loads absorbed and transmitted by each of the front-row positions during a scrum.16

Investigation of the injury profile of players in individual positions has not been undertaken in any detail. The purpose of the current study was to present match injury profile data as a function of days of absence and playing position compared with other forwards or backs.

Methods

Participants

The study has been described in detail previously.17 In summary, 899 players (488 forwards and 411 backs) from 14 English Premiership clubs took part. Players were included or excluded from the study when they became or ceased to be members of the club's first team squad. The average team squad size was 39 players. Written informed consent was obtained from each subject.

Injury definition

The injury definition used in the study was: ‘any injury that prevents a player from taking a full part in all training and match play activities typically planned for that day for a period of greater than 24 h from midnight at the end of the day the injury was sustained.’ Injury severity was defined by the number of days of absence before a player returned to full fitness; full fitness was defined as ‘able to take a full part in training activities (typically planned for that day) and available for match selection.’ Absences due to illness and non-sport-related medical conditions were not included in the study. The injury definitions and data-collection methods utilised in this study are compliant with the institutional review board consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union.18

Data collection

Medical personnel at each club reported all match injury episodes on a weekly basis. They also completed a standard injury report form for each injury which detailed the injury diagnosis using a modified Orchard Sports Injury Classification System19 and associated injury information including injury event and playing position at the time of injury. Individual player match exposure data were recorded every week for each player; this identified the position played and the total time on the field in competitive matches.

Data analysis

Seven forward playing positions (loose-head prop, hooker, tight-head prop, second-rows (2), blind-side flanker, open-side flanker and number-8) and five back positions (scrum-half, fly-half, centres (2), wingers (2) and full-back) were used for analysis purposes. Results for each playing position were compared with data for the remaining forwards or backs. The incidence of match injury was recorded as the number of injuries/1000 player-hours of match exposure, the average severity of injury was recorded as the number of days of absence, and the days of absence due to injury were recorded as the total number of days of absence/1000 player-hours of match exposure. Differences in the days of absence due to match injuries between groups were considered significant if the 95% CI of the days of absence risk ratios for the groups did not include the value of 1.0, and the p value (Z test for the comparison of rates) was less than 0.05.20 Injury locations causing more than 150 days of absence/1000 player-hours were classified as injury-prevention priorities because, in total, they were responsible for 50% or more of the total days of absence due to match injuries (forwards: 50%; backs: 54%).

Results

Number of injuries and days of absence

A total of 1307 injuries to forwards (loose-head props: 157; hookers: 192; tight-head props: 189; second-rows: 306; blind-side flankers: 150; open-side flankers: 153; number-8s: 160) and 1177 injuries to backs (scrum-halves: 143; fly-halves: 198; centres: 356; wingers: 320; full-backs: 160) were reported. These injuries caused 25 269 days of absence to forwards (loose-head props: 2952; hookers: 3689; tight-head props: 3254; second-rows: 5916; blind-side flankers: 2652; open-side flankers: 3471; number-8s: 3335) and 21 345 days of absence to backs (scrum-halves: 3117; fly-halves: 3017; centres: 6558; wingers: 5963; full-backs: 2690). In total there were 30 267 h of match exposure reported (forwards: 16 103 h; backs: 14 164 h). There were no significant differences in total days of absence/1000 player-hours due to injury between players in different positions within the forwards (figure 1) and the backs (figure 2).

Figure 1

Incidence, average severity and days of absence due to injury for forwards. Bubble size: days of absence/1000 player-hours.

Figure 2

Incidence, average severity and days of absence due to injury for backs. Bubble size: days of absence/1000 player-hours.

Loose-head prop's injury profile

Absence due to neck injuries was higher for loose-head props (161 days of absence/1000 player-hours) (p=0.13) because of a significantly higher absence from cervical disc/nerve root injuries (figure 3). The majority of these injuries were sustained during tackling (57%) and scrummaging (29%). There was also a significantly higher absence due to shoulder rotator cuff injuries (scrummaging: 66% (75% of these to the right shoulder)) and a significantly higher absence due to chest injuries (p=0.03) due to a significantly higher absence due to rib fractures and contusions and pneumothoraces.

Figure 3

Days of absence injury profile for loose-head props. *Significantly different from other forwards (p<0.05). ACL, anterior cruciate ligament.

Hooker's injury profile

Absence due to shoulder injuries was significantly higher for hookers (p=0.01) because of a significantly greater absence from rotator cuff injuries (figure 4) (tackling: 57%). Absence due to neck injuries was higher (p=0.24) because of a significantly greater absence due to cervical disc/nerve root injuries. The majority of these were sustained during tackling (38%), collisions (25%) and scrummaging (19%).

Figure 4

Days of absence injury profile for hookers. *Significantly different from other forwards (p<0.05). ACL, anterior cruciate ligament.

Tight-head prop's injury profile

Absence due to lumbar spine injuries (p<0.001) because of a significantly greater absence from lumbar disc/nerve root and soft tissue injuries and absence due to lower leg injuries (p<0.001) because of a significantly greater absence due to calf muscle injuries were both significantly higher for tight-head props (figure 5). Calf-muscle injuries were predominately sustained during scrummaging (54%) and running (33%), lumbar disc/nerve root injuries and lumbar soft tissue injuries during scrummaging (67% and 57% respectively).

Figure 5

Days of absence injury profile for tight-head props. *Significantly different from other forwards (p<0.05). ACL, anterior cruciate ligament.

Second-row's injury profile

Absence due to ankle/heel injuries (p=0.14) was higher in second-row forwards because of a significantly greater absence due to ankle lateral ligament injuries (figure 6). A higher proportion of these injuries were sustained in the lineout (21%) compared with other forwards.

Figure 6

Days of absence injury profile for second-rows. *Significantly different from other forwards (p<0.05). ACL, anterior cruciate ligament; MCL, medial collateral ligament.

Blind-side flanker's injury profile

Absence due to thigh injuries was significantly higher in blind-side flankers (p=0.04) because of a greater absence due to hamstring muscle injuries (predominately sustained during running: 86%) (figure 7).

Figure 7

Days of absence injury profile for blind-side flankers. *Significantly different from other forwards (p<0.05).

Open-side flanker's injury profile

Absence due to neck injuries (p=0.01) was significantly higher for open-side flankers (sustained predominately in the tackle: 63%) because of a significantly greater absence due to cervical facet joint injuries (figure 8). Absence due to shoulder injuries (p=0.11) because of a significantly greater absence due to acromio-clavicular joint injuries and absence due to ankle/heel injuries (p=0.06) because of a significantly greater absence due to ankle joint capsule sprains/jars were also higher.

Figure 8

Days of absence injury profile for open-side flankers. *Significantly different from other forwards (p<0.05). ACL, anterior cruciate ligament; MCL, medial collateral ligament.

Number-8's injury profile

Absence due to arm and hand injuries was significantly higher in number-8s (p<0.001) because of a significantly greater absence due to biceps muscle injuries and wrist/hand fractures (figure 9). Absence due to knee injuries (p=0.16) because of a significantly greater absence due to patella tendon injuries was also higher.

Figure 9

Days of absence injury profile for number-8s. *Significantly different from other forwards (p<0.05). MCL, medial collateral ligament.

Scrum-half's injury profile

Absence due to lumbar spine injuries was significantly higher in scrum-halves (p<0.001) because of a significantly greater absence from lumbar disc/nerve root and soft tissue (including muscle strain) injuries (figure 10). Absence due to shoulder injuries was significantly higher in scrum-halves (0.04) because of a significantly greater absence from acromioclavicular joint injuries. Absence due to thigh injuries (p<0.001) was significantly lower in scrum-halves due to a significantly lower absence due to hamstring muscle injuries (p=0.001).

Figure 10

Days of absence injury profile for scrum-halves. *Significantly different from other backs (p<0.05). ACL, anterior cruciate ligament.

Fly-half injuries

Absence due to thigh injuries (p=0.01) because of significantly greater absence due to hamstring muscle injuries and absence due to arm and hand injuries (p=0.001) because of a significantly greater absence due to elbow joint injuries were both significantly higher in fly-halves (figure 11).

Figure 11

Days of absence injury profile for fly-halves. *Significantly different from other backs (p<0.05). MCL, medial collateral ligament.

Centre's injury profile

Absence due to head injuries (p<0.001) (tackling: 44%; being tackled: 39%) because of a significantly greater absence due to concussion, absence due to neck injuries (p=0.005) (being tackled: 46%; tackling: 42%) because of a significantly greater absence due to cervical disc/nerve root injuries, absence due to shoulder injuries (p=0.01) (tackling 68%; being tackled: 18%) because of a greater absence due to shoulder dislocation/instability and absence due to lower leg injuries (p=0.001) because of a greater absence due to tibia/fibula fractures were all significantly higher in centres (figure 12).

Figure 12

Days of absence injury profile for centres. *Significantly different from other backs (p<0.05). LCL, lateral collateral ligament; MCL, medial collateral ligament; PCL, posterior cruciate ligament.

Winger's injury profile

Absence due to thigh injuries (p=0.001) was significantly higher in wingers because of a significantly greater absence due to thigh haematomas (figure 13). Absence due to head (p<0.001) and shoulder (p=0.02) injuries was significantly lower.

Figure 13

Days of absence injury profile for wingers. *Significantly different from other backs (p<0.05). MCL, medial collateral ligament.

Full-back injuries

Absence due to groin/hip/buttock injuries was significantly higher in full-backs (p<0.001) because of a greater absence due to groin nerve entrapment injuries (figure 14). Absence due to chest injuries was significantly higher in full-backs (p=0.03) due to a greater absence from costochondral/sternal injuries and rib fractures/contusions.

Figure 14

Days of absence injury profile for full-backs. *Significantly different from other backs (p<0.05).

Injury-prevention priorities for players by playing position

The injury-prevention priorities for players by playing position are summarised in table 1.

Table 1

Injury locations of highest injury risk for players in each playing position

Discussion

Absence due to match injuries was not significantly higher in any of the individual playing positions within the forwards and backs in the current study. This is consistent with other large rugby union epidemiological studies where few differences have also been reported in injury incidence between positions.17 21 22 Nevertheless, players in every position still missed a significant number of days of absence due to match injuries (forwards: 1569 days of absence/1000 player-hours equivalent to 33 days of absence per match due to forwards injuries; backs 1507 days of absence/1000 player-hours equivalent to 28 days of absence per match due to backs injuries). There is a clear need to design and implement injury-prevention programmes for all players to reduce this injury burden.

Three main body locations (the shoulder, knee and ankle/heel) for forwards and three main body locations (the shoulder, hamstring and knee) for backs caused more than 150 days of absence/1000 player-hours; this constituted more than half of all days of absence due to match injuries. As a result, injury-prevention strategies for injuries to these four body regions should be prioritised. Studies implementing injury-prevention interventions in other non-collision sports have been successful at reducing the incidence of injury to all of these lower-limb locations (hamstrings, knees and ankles) by utilising exercises designed to improve parameters such as propriception, core stability and muscle strength.23,,30 While the need for more research into the effectiveness of injury-prevention interventions in collision sports is recognised, it is likely that interventional approaches used in other sports would be transferrable to the rugby union population. Fewer studies have attempted to prevent shoulder injuries by using controlled injury-prevention interventions, although reducing shoulder capsular tightness31 and eccentric resistance training32 have been highlighted.

Despite the lack of differences in total absence due to injury for each playing position and the identification of three principal body regions for injury-prevention programmes for the majority of forwards and backs, significant differences in injury profile between players in different playing positions were reported. These can be used to focus further on injury-prevention programmes.

Loose-head props and hookers both exhibited similar injury profiles. Cervical injuries, in particular cervical disc/nerve root injuries, caused significantly greater absence compared with other forwards. It has long been established that the risk of sustaining a cervical injury is higher in front-row forwards, in particular during scrummaging;8 11 33,,36 however, in the current study, tackling was the most common cause of cervical disc/nerve root injuries for these players. Nevertheless, the greater impact forces on scrum engagement and the loads transmitted and absorbed by front-row forwards during scrummaging16 37 may have predisposed these players to cervical injuries. This may have been exacerbated by the greater use of the neck extensors during scrummaging for loose-head props and hookers. Development of the cervical musculature may be of benefit in preventing cervical injuries in these players,38 although the detail of the intervention needs more investigation.

Shoulder rotator cuff injuries also caused significantly more absence in loose-head props and hookers. A large proportion of these injuries to loose-heads were due to scrummaging (66%), although the majority of these were to their right shoulder (75%), which is bound to the hooker rather than the opposition. None of the rotator cuff injuries to hookers were sustained during scrummaging. Factors that might result in these players being more predisposed to rotator cuff injuries14 include rotator cuff weakness,39 fatigue-induced propriception and skill deficits40 41 and suboptimal glenhumeral alignment.42 The high impact forces and loads experienced during scrummaging16 37 and the repetitive demands placed on hookers from throwing the ball into the lineout in matches and training may also increase the risk of injury to these players.

Tight-head props exhibited a different injury profile from the other front-row positions. Lower leg and lumbar spine injuries caused significantly more absence compared with other forwards due to a significantly greater absence from calf muscle strains, lumbar disc/nerve root and lumbar soft tissue injuries; trends that have been identified previously.11 43 The majority of all of these injuries were sustained during scrummaging (54–67%). It has been shown that greater loads are transmitted by tight-head props during scrummaging than by all other forwards.16 The inability of the lumbar spine and calf musculature of tight-head props to adapt to these high loads therefore needs addressing. Improving scrummaging technique to ensure the lumbar spine is maintained in a strong neutral position by improving neuromuscular control44 and specific strength training for the lumbar and calf regions are plausible interventions.45 46 The association between lumbar spine pathology and calf muscle symptoms or strains should also not be overlooked.47

Absence due to lateral ankle ligament injuries was significantly higher in second-rows, and a higher proportion of these injuries were sustained in the lineout (21%) compared with other forwards. This is similar to previous findings15 where inversion ankle injuries on landing from a lineout lift was felt to be a significant risk factor. Landing from a jump is a common cause of ankle injuries in other sports such as soccer48 and volleyball.49 Injury-prevention interventions that have focussed on adopting the correct lower-limb alignment when landing have been successful at reducing the incidence of ankle injuries in other sports.23 27 30

Blind-side flankers had more absence due to thigh injuries than other forwards, in particular due to hamstring muscle injuries. The majority of these injuries were sustained during running (86%), typically during sprinting or running at high speed.28 50 The back-row perform between 1.4 and 2 times as many sprints in a match compared with other forwards.51 52 Eccentric strengthening of the hamstrings,10 24 improving hamstring flexibility53,,55 and sports-specific conditioning28 have all been successful at reducing the incidence of hamstring injuries.

Absence due to neck injuries, in particular cervical facet joint injuries, was significantly higher in open-side flankers. The tackle is the most common cause of absence due to injury largely because it is the most frequent contact event.56 Open side flankers make more tackles than players in other positions during a match,57 and the majority of open-side neck injuries were sustained in the tackle (63%). Open-side flankers may benefit from gains in cervical musculature strength38 to improve their ability to adapt to high impact forces on their neck, as well as improvements in tackling technique previously advocated.17

The significant differences in the injury profile of the number-8, namely greater absence due to arm and hand injuries and foot injuries, were largely as a consequence of injuries for which injury-prevention strategies are less well validated, namely wrist, hand and foot fractures and biceps muscle injuries.

While absence due to shoulder and knee injuries was high in scrum-halves, as with other backs, absence due to lumbar spine injuries, more specifically lumbar disc/nerve root injuries, caused significantly more days of absence for scrum halves than for other backs. The repeated lumbar flexion and rotation necessary to pass the ball off the ground might predispose these players to lumbar injury. Optimising global and local muscular control of this combined lumbar movements is advocated as a possible injury-prevention strategy.44 45 However, the repeated lumbar flexion and rotation may have positively conditioned the hamstrings of these players by increasing hamstring flexibility53,,55 and eccentric strength10 24 resulting in the significantly lower absence due to hamstring muscle injuries observed.

Fly-halves had a significantly greater absence due to thigh injuries, specifically hamstring muscle injuries, compared with other backs. A high incidence of hamstring muscle injuries in sports that involve a lot of kicking has been previously reported58,,60 and the frequency with which fly-halves kick the ball during a match compared with other positions may predispose them to an increased risk of hamstring muscle injury, although this has yet to be confirmed. Greater absence due to arm and hand injuries was largely as a consequence of injuries for which injury-prevention strategies are less well validated, namely elbow joint injuries, while the significantly lower absence from shoulder injuries may be due to fly-halves making fewer tackles in a match compared with other backs.57

The observation that absence due to head injuries, in particular concussions, was significantly higher in centres compared with other backs has been reported previously.13 Absence due to neck and shoulder injuries was also significantly higher in centres compared with other backs, and the most common injury event was tackling (42–68%). High speed going into the tackle, high impact force and contact with the tackler's head and neck have all been identified previously as significant risk factors for tacklers.57 61 Centres tend to make more tackles in a match than other backs57 and have been significantly more prone to injury when tackling than players in other positions.61

While absence due to thigh injuries was high for the majority of backs, it was significantly higher for wingers compared with other backs. One might expect that this greater absence would be due to hamstring muscle injuries because of the greater number of sprints performed in a match by outside backs52 and as a consequence of the faster running speed of these players. While absence due to hamstring muscle injuries was high in wingers, it was the absence due to thigh haematomas that was most significant.

The significant differences in the injury profile of the full-backs, namely greater absence due to groin/hip/buttock injuries and chest injuries, were largely as a consequence of injuries for which injury-prevention strategies are less well validated, namely groin nerve entrapment injuries, costochondral/sternal injuries and rib fractures/contusions.

We believe that this study demonstrates the need for injury-prevention programmes for all players and that playing position should be considered as an independent risk factor for injury and consequently as a driver for individualised injury-prevention programmes. While significant absence due to injury to three body regions was relatively consistent for all positions within the forwards (shoulder, knee and ankle/heel) and the backs (shoulder, hamstring and knee), significant differences in the injury profile between positions demonstrate the need for injury-prevention programmes to be position-specific. Such programmes should also be player-specific and recognise the importance of focusing on a player's previous injury history because of the significantly greater absence due to recurrent injuries compared with new injuries.17 In the future, our understanding of differences in the injury profile between different positions could be further enhanced by a greater understanding of the position-specific demands of the game and the mechanism of injury.

What is already known about this topic

Trends in the profile of injuries sustained in rugby union matches between different positions have been reported in the literature on several occasions. However, the injury profile has typically only been reported for grouped playing positions, such as front-row forwards or midfield backs, rather than for individual playing positions.

What this study adds

This study demonstrates that there are individual position-specific differences in match injury profile that in conjunction with a player's past injury history can be used to design more targeted injury-prevention programmes in rugby union.

Acknowledgments

The authors thank C Fuller (Centre for Sports Medicine, University of Nottingham) for his key role in initiating and supporting the project (England Rugby Injury and Training Audit). The authors thank the doctors, physiotherapists, and fitness, strength and conditioning staff from the following clubs and teams who have recorded injury and training information throughout the project: Bath Rugby, Bristol Rugby, Gloucester RFC, England, Leeds Tykes, Leicester Tigers, London Irish, London Wasps, Harlequins, Newcastle Falcons, Northampton Saints, Rotherham, Sale Sharks, Saracens and Worcester Warriors. The authors also thank the Rugby Football Union for their financial support and R Vickers (Rugby Football Union) and T Cleary (Rugby Football Union) for their help in collecting and processing the data.

References

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Footnotes

  • Funding Rugby Football Union.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.

    Detail has been removed from this case description or these case descriptions to ensure anonymity. The editors and reviewers have seen the detailed information available and are satisfied that the information backs up the case the authors are making.

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