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The epidemiology of foot injuries in professional rugby union players
Foot and Ankle Surgery 17 (2011) 113–118
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The epidemiology of foot injuries in professional rugby union players Christopher J. Pearce FRCS(Tr&Orth), MFSEM(UK)a,*, John H.M. Brooks PhDd, Simon P.T. Kemp MA, MBBS, FFSEM(UK&I)d, James D.F. Calder MD, FRCS(Tr&Orth), FFSEM(UK)b,c a
Trauma & Orthopaedic Dept, Royal Surrey County Hospital, Egerton Road, Guildford, Surrey, UK Trauma & Orthopaedic Dept, North Hampshire Hospital Foundation Trust, Aldermaston Road, Basingstoke, Hampshire, UK c Imperial College London School of Medicine, London, UK d Rugby Football Union, Twickenham, London, UK b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 December 2009 Received in revised form 22 January 2010 Accepted 7 February 2010
Background: Foot injuries represent a small but important proportion of injuries to professional rugby union players. There are no detailed epidemiological studies regarding these injuries. The aim of this study was to describe the epidemiology of foot injuries sustained by a cohort of professional rugby union players and identify areas that may be targeted for injury prevention in the future. Methods: Medical personnel prospectively recorded injuries in professional Premiership rugby union players in England over four seasons. Injuries to the foot were identified and the time away from training and playing was reported. Results: A total of 147 foot injuries were sustained resulting in 3542 days of absence in total. Acute events accounted for 73% of all foot injuries, with chronic, mostly overuse conditions, accounting for 25% (undiagnosed 2%). Chronic conditions led to proportionately more time away from training and playing (p = <0.001). Specifically, stress fractures in the foot accounted for 8% of the total foot injuries but 22% of the absence. Navicular stress fractures had the longest recovery time with the mean return to training and match play of 188 days. Conclusion: In collision sports such as rugby, some injuries may be inevitable but clinicians should always be seeking ways to minimise their occurrence and impact. This study revealed a high proportion of morbidity associated with chronic and overuse foot injuries in these professional athletes. With greater attention paid to risk factors, some of these injuries, and importantly, recurrent injuries may be avoided. ß 2010 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Rugby union Foot Injury Epidemiology
1. Introduction Rugby union is one of the most popular team collision sports in the world [24]. More than three million people in more than 100 countries across five continents play the sport annually [11]. In a questionnaire study involving over 17,000 adults between 1987 and 1990, rugby had the highest injury rate of all sports in the UK with 95.7 exercise related morbidity episodes reported per 1000 occasions of participation [34]. Injury rates increase with higher levels of play in many sports including rugby union [3,5,17,38,43]. Rugby union maintained amateur standing from the mid-19th century until after the World Cup in 1995. The injury rate in rugby appears to have increased considerably since the start of the professional era [3,17].
* Corresponding author at: 20 Topiary Square, Stanmore Road, Richmond, Surrey TW92DB, UK. Tel.: +44 (0)7976356076. E-mail address: [email protected] (C.J. Pearce).
Garraway et al. demonstrated this increase in injuries in both professional and amateur players since the game became professional at the top level [17]. Professional full-time training has resulted in increased player skill, strength, power and fitness as well as an increased mean body mass of the elite players [11]. Rule changes designed to create a more flowing game have meant that the ball-in-play time has increased considerably, for example; from 1603 s at the Rugby World Cup in 1995 to 1997 s in 2003 (a 25% increase) [11]. The lower limb is the most commonly injured anatomical region, accounting for approximately 42–59% of all injuries sustained at the elite level [3,8,9,23]. Foot injuries represent a small but important proportion of injuries to professional rugby union players [23], however, there are no detailed epidemiological studies regarding these injuries. The aim of this study was to describe the epidemiology and review the risk factors associated with foot injuries sustained by a cohort of professional rugby union players with a view to identifying potential future strategies for injury prevention.
1268-7731/$ – see front matter ß 2010 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2010.02.004
C.J. Pearce et al. / Foot and Ankle Surgery 17 (2011) 113–118
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2. Methods
3. Results
2.1. Injury assessment
The study involved a total of 33,340 h of match exposure (forwards: 17,758; backs: 15,583) and 395,223 h of training exposure (forwards: 223,096; backs: 172,127). During this period 147 foot injuries were sustained resulting in 3542 days of absence. Table 1 gives an overview of the number and severity of foot injuries sustained by forwards and backs during training and match play. Overall, foot injuries accounted for 4% of all the injuries recorded and led to 5% of the absence from playing and training. The incidence of foot injuries sustained during match play was significantly higher than the incidence during training (3.3 compared with 0.09 injuries per 1000 player-hours [95% CI, 2.7– 4.0 and 0.07–0.13]) (p < 0.001). There was no difference between forwards and backs in terms of foot injury incidence during match play with both sets of players sustaining 3.3 injuries per 1000 player-hours [95% CI, 2.5–4.2]. Backs sustained more injuries than forwards in training (0.12 compared with 0.08 injuries per 1000 player-hours [95% CI, 0.07–0.18 and 0.05–0.12]) but this was not statistically significant (p = 0.20). The mean severity of each foot injury was 24 days absence (95% CI, 19–28) (match: 27 [95% CI, 22–23]; training: 16 [95% CI, 11– 21]). The mean severity of injuries was higher for forwards in matches than for backs (31 compared with 23 [95% CI, 22–40 and 17–30]). However the mean severity of training injuries was higher for backs than for forwards (backs: 18 [95% CI, 11–27]; forwards: 13 [95% CI, 8–21]). These differences were not significant (p = 0.13 and 0.37, respectively). The total days absence due to match foot injuries was 89 per 1000 player-hours [95% CI, 74–107] while for training injuries it was 1.5 per 1000 player-hours [95% CI, 1.1–2.0] (p < 0.001). There was no statistical difference between forwards and backs in terms of days absence due to foot injuries sustained during matches (forwards, 100 [95% CI, 77–129]; backs, 77 [95% CI, 58–100] (p = 0.16)). However backs lost significantly more days in total due to training foot injuries than forwards (backs, 2.0 [95% CI, 1.3–3.2]; forwards, 1.0 [95% CI, 1.1–2.0] (p = 0.03)), although the total number of days lost were very small. There were no significant differences in the overall incidence and average severity of foot injuries sustained during matches for forwards or backs as a function of player’s playing position (Table 2) or body mass (Tables 3 and 4) except for backs of body mass between 85 and 99.9 kg who had a significantly lower average severity of foot injuries (Table 4).
A prospective study was performed involving a male cohort of 899 professional rugby union players consisting of 488 forwards and 411 backs from 14 English Premiership Rugby Union clubs over 4 seasons (2002–2004 and 2005–2007). The main survey methods have been described previously [8,9] and were compliant with the consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union [15,16]. All players were members of the clubs’ firstteam squad and were professional rugby players. Only six eligible players refused to take part, and the rest gave their written consent to be included. The ethics committee deemed that ethics approval was not required because the study did not involve hospital patients or any invasive procedures on the participants. The time-loss injury definition used was as follows: ‘‘any injury to the foot that prevents a player from taking full part in all training and match play activities planned for that day, for a period of 24 h from midnight at the end of the day that the injury was sustained.’’ Individual match exposure (number of player-hours) was recorded for each player, and team fitness coaches recorded volume of training exposure on a weekly basis. Medical personnel including both physiotherapists and physicians affiliated with the clubs prospectively recorded all injuries to the players in England over the four seasons. Injuries to the foot were identified and the time away from training and playing was recorded and reported. Foot injuries were classified according to a modified Orchard Sports Injury Classification System [35]. A standard injury form was completed in which associated injury detail was provided. The foot injuries were diagnosed by clinical examination, radiographs, ultrasound scan, MRI scan, or a combination of these. Recurrence of an injury was diagnosed by the medical personnel affiliated with the club using their clinical judgement that it was the same injury in the same location as previously. 2.2. Data analysis The incidence rate was defined as the number of injuries per 1000 player-hours of match exposure for match injuries or injuries per 1000 player-hours of training for training injuries. Injury severity was defined as the number of days taken to return to full fitness. Full fitness was defined as the player being able to take full part in the training activities planned for that day and be available for match selection. Statistical analysis was performed using Microsoft Office Excel 2007. A Z-test, utilizing the standard deviation of the study population as a whole, was used to identify significant differences in the number of injuries and severity of those injuries between the categorical groups. Statistical significance was accepted if p < 0.05.
3.1. Acute and chronic injuries Table 5 shows all of the foot injury categories with their proportions in terms of incidence and severity as well as the average severity and total absence for each injury. Acute events accounted for 73% of all foot injuries, with chronic, mostly overuse conditions, accounting for 25% and the other 2% made up of undiagnosed foot pain resulting in absence from training and matches.
Table 1 Number and severity of foot injuries. Match injuries
Forwards Backs All players
Training injuries
All injuries
Number of injuries
Average severity (days)
Total absence (days)
Number of injuries
Average severity (days)
Total absence (days)
Number of injuries
Average severity (days)
Total absence (days)
58 52 110
31 23 27
1774 1193 2967
17 20 37
13 18 16
223 352 575
75 72 147
27 21 24
1997 1545 3542
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Table 2 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries as a function of playing position. Playing position
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
Front-row (reference) Second-row Back-row Inside backs Midfield backs Outside backs
2.63 3.18 3.04 3.19 1.74 3.29
* 1.21 1.16 1.21 0.66 1.25
* 0.60 0.67 0.60 0.37 0.50
25 30 35 29 16 22
* 1.21 1.41 1.15 0.65 0.89
* 0.61 0.32 0.70 0.34 0.73
(1.61–4.29) (1.85–5.48) (1.91–4.82) (1.85–5.49) (0.83–3.66) (2.12–5.10)
(0.58–2.52) (0.59–2.27) (0.58–2.53) (0.27–1.61) (0.65–2.42)
(15–41) (18–52) (22–56) (17–49) (8–34) (14–34)
(0.58–2.51) (0.72–2.76) (0.55–2.39) (0.27–1.57) (0.46–1.72)
Table 3 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries for forwards as a function of body mass. Body mass (kg)
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
85–99.9 (reference) 100–114.9 115–135
1.84 (0.59–5.72) 3.52 (2.53–4.91) 2.16 (1.16–4.02)
* 1.91 (0.59–6.21) 1.17 (0.32–4.26)
* 0.28 0.81
63 (20–196) 26 (19–36) 34 (18–63)
* 0.41 (0.13–1.32) 0.54 (0.15–1.95)
* 0.14 0.34
Table 4 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries for backs as a function of body mass. Body mass (kg)
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
70–84.9 (reference) 85–99.9 100–114.9
3.63 (1.89–6.97) 2.21 (1.45–3.35) 4.34 (2.07–9.10)
* 0.61 (0.28–1.32) 1.20 (0.45–3.21)
* 0.21 0.73
40 (21–78) 15 (10–22) 31 (15–66)
* 0.36 (0.17–0.79) 0.78 (0.29–2.08)
* 0.01 0.62
There were significantly more acute foot injuries (2.5 injuries per 1000 player-hours [95% CI, 2.0–3.1]) than chronic injuries (0.7 injuries per 1000 player-hours [95% CI, 0.5–1.1]) diagnosed during match play (p < 0.001). This trend was also seen in injuries diagnosed during training (acute, 0.06 [95% CI, 0.04–0.09]; chronic, 0.03 [95% CI, 0.02–0.06]) but it was not statistically significant (p = 0.08). Chronic conditions sustained in both matches and training however had a significantly higher mean severity (Table 6). Consequently chronic foot injuries resulted in proportionately more time away from training and playing (45%), compared with the number of chronic injuries (25%). A specific example is that of stress fractures in the foot which only accounted for 8% of the total foot injuries but 22% of the absence (Table 2). Navicular stress fractures had the longest recovery time with a mean return to training and match play of 188 days. 3.2. Recurrent absence due to overuse injuries Fig. 1 shows the proportion of newly diagnosed and recurrent injuries in this series. There were over twice as many newly
Fig. 1. Graph showing proportion of newly diagnosed and recurrent injuries.
diagnosed chronic and overuse injuries as recurrences of a previously diagnosed chronic condition. The mean recovery time from recurrent chronic conditions, however was 99 days [95% CI, 49–198], significantly higher than 28 days [95% CI, 19–41] for the newly diagnosed chronic injuries (severity ratio 3.5 [95% CI, 1.6– 7.7] (p < 0.02)). 4. Discussion Comparing the results of different studies on rugby injuries requires some caution as injury definitions (time loss, missed matches, diagnostic assessment and surgery), the definition of recurrent injury, methods of reporting injuries (number, proportions and incidence) and the method of calculating incidence (injuries per 1000 player-hours, per 1000 athlete-exposures and per 1000 matches) differ [6]. Consequently proportions are often used when comparing studies. In the current study, foot injuries represented 4% all injuries sustained, similar to the proportion found another study of a similar group of players in the professional era [3]. Difficulties with inter-study foot injury incidence comparisons are compounded by the fact that studies often group foot and ankle injuries together [4,17], while others group foot injuries into ‘other’ injuries [5]. It is possible, however, that there has been an increase in the proportion of foot injuries sustained in the professional era compared to injuries to other parts of the body. A survey of 356 rugby union players enrolled in the Rugby Injury and Performance Project cohort in New Zealand in 1993 revealed that the foot only accounted for 1% of all the injuries reported [19] compared with 4% in the current study. There are many potential confounding factors but this does raise the possibility that the higher profile injuries, such as knee and shoulder injuries have, perhaps rightly, been more successfully targeted for injury prevention than those of the foot. Previous epidemiological studies of injuries sustained in rugby union have concentrated on risk factors such as playing position, the period of the match and/or season in which the injury was
C.J. Pearce et al. / Foot and Ankle Surgery 17 (2011) 113–118
116 Table 5 Injury diagnosis. Injury category
Injury diagnosis
Number of injuries
Acute fracture
Cuboid acute fracture Cuneiform acute fracture Fourth metatarsal acute fracture Fractured metatarsal(s) Fractured phalanx (foot) Multiple metatarsal fractures Navicular acute fracture Second metatarsal acute fracture
Proportion of foot injuries
Average severity
Days absence
Proportion of foot injuries absence
1 1 2 2 4 1 2 1
1% 1% 1% 1% 3% 1% 1% 1%
35 37 8 51 21 134 48 82
35 37 15 101 83 134 95 82
1% 1% 0% 3% 2% 4% 3% 2%
Dislocated joint(s) of foot (incl. Lisfranc injury) Foot ligament sprain (including spring ligament) Interphalangeal ligament disruption Ruptured volar plate first MTP joint Sprain foot joint Sprained toe/turf toe
14 1 9 2 1 29 16
10% 1% 6% 1% 1% 20% 11%
42 7 10 22 89 18 22
582 7 87 44 89 534 352
16% 0% 2% 1% 3% 15% 10%
Foot blistering Foot haematoma Foot laceration Foot muscle strain Heel fat pad bruise Toenail problem/haematoma
58 2 21 1 3 6 2
39% 1% 14% 1% 2% 4% 1%
19 4 8 8 7 4 3
1113 7 166 8 22 25 5
31% 0% 5% 0% 1% 1% 0%
Cuboid stress fracture Fifth metatarsal stress fracture Navicular stress fracture Second metatarsal stress fracture Sesamoid stress fracture Stress fracture metatarsal Stress fracture midtarsal bone (navicular, cuneiform, cuboid) Third metatarsal stress fracture
35 1 2 2 1 3 1 1 1
24% 1% 1% 1% 1% 2% 1% 1% 1%
7 16 60 188 55 39 27 8 54
233 16 119 375 55 118 27 8 54
7% 0% 3% 11% 2% 3% 1% 0% 2%
First metatarsophalangeal joint degenerative arthritis Symptomatic accessory bone of foot
12 1 1
8% 1% 1%
772 2 99
64 2 99
22% 0% 3%
2 2 1 7
1% 1% 1% 5%
101 13 53 50
51 26 53 347
3% 1% 1% 10%
All chronic forefoot disorders Chronic soft-tissue disorder Cuboid syndrome or foot peroneal tendonitis Distal plantar fascitis Plantar fascitis/strain/calcaneal spur Tibialis posterior insertion tendonitis
10 4 1 7 1
7% 3% 1% 5% 1%
426 17 2 29 12
43 66 2 204 12
12% 2% 0% 6% 0%
All chronic soft-tissue disorders Foot pain undiagnosed Foot pain undiagnosed
13 3
9% 2%
284 10
22 31
8% 1%
All acute fractures Acute joint injury
All acute joint injuries Acute soft-tissue injury
All acute soft-tissue injuries Stress fracture
All stress fractures Chronic joint disorder
All chronic joint disorders Chronic forefoot disorder
Metatarsalgia Mortons neuroma or Joplins neuritis Sesamoiditis/first metatarsophalangeal joint pain
All foot pain undiagnosed All foot injuries
sustained, training volume and the phase of play [3,5,7– 10,17,19,23,41,43]. No study has so far differentiated between the chronic, overuse injuries and the acute injuries, probably partly because it is less relevant in other areas of the body than in the foot. Even studies which have evaluated the state of the pitch (e.g. playing on hard ground) with regard to injury rates have not made this distinction [1,28,42].
3
2%
31
10
1%
147
100%
24
3542
100%
The majority of investigations into overuse injuries in athletes have involved runners, where these types of injury predominate. There can be no doubt that the volume and intensity of training play a major contributory role [26,27,31,47]. In a study of training volumes in professional rugby, an increase in the average number of training injuries and the average number of days lost per team per week was seen when higher training volumes were performed.
Table 6 Average severity (days) of chronic and acute injuries. Match injuries
Chronic Acute
Training injuries
All injuries
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
52 (35–77) 20 (16–25)
2.5 (1.6–4.0) Ref
<0.001 Ref
26 (15–45) 10 (7–14)
2.7 (1.4–5.3) Ref
0.004 Ref
43 (31–59) 18 (15–22)
2.4 (1.6–3.5) Ref
<0.001 Ref
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The most common training injury locations in this study again were to the lower limb [7]. With the greater exposure to training and playing involved in professional rugby union we should expect to see a greater incidence of, and absence due to, overuse conditions including stress fractures. Previous reports have stated that stress fractures account for up to 10% of sports overuse injuries [27,33]. In this series of rugby union professionals, stress fractures accounted for 8.2% of all injuries to the foot and 32% of the chronic foot injuries. The current study found that chronic/overuse injuries to the foot led to a disproportionate period of absence from training and playing than acute injuries. In fact, a navicular stress fracture is second only to an ACL rupture as the injury with the greatest mean severity in professional rugby [8,9]. Tarsal stress fractures have been shown by other investigators to take the longest of all stress fractures to recover from [32]. It is important to make the distinction between acute and chronic injuries because, while some acute injuries may be inevitable in a collision sport such as rugby, chronic conditions should be more easily targeted for injury prevention strategies. Additionally, club physiotherapists, physicians and the players themselves are in a better position to instigate injury prevention measures for an overuse injury than an acute injury as acute injury prevention is influenced more strongly by the laws of the game which are typically out of their direct control. Another reason to concentrate attention on the chronic and overuse conditions as, highlighted by this study, is that recurrent absence due to an injury of this type takes up to four times longer to recover from than a new presentation. Club medical staff need to be extra vigilant to avoid incomplete treatment and thoroughly investigate and treat any contributory factors in these players. Many intrinsic and extrinsic risk factors for the development of stress fractures in athletes have been reported, some with more relevance to professional rugby than others [2,12,18,21,27,32, 33,37,45]. The subtle cavo-varus foot in the athlete has long been recognised [44], and has recently been gaining more attention as being a significant risk factor for various overuse conditions and especially stress fractures and recurrent stress fractures [25,27,30]. This foot shape is known to be relatively rigid with a poor capacity for shock attenuation and increased initial peak forces have been recorded in runners with high arches [46,48,49]. Most of the work measuring the forces acting on feet has concentrated on running in a straight line, however one study has shown that these forces are significantly increased during cutting, jumping and landing, all of which feature frequently in rugby. Different athletic shoes afforded various levels of protection from these forces [36]. Similar findings have also been reported in soccer [14]. Wright et al. reported that patients with Jones fractures (basal 5th metatarsal) had a twofold increase in peak pressures at the base of the fifth metatarsal head compared to a control group and that athletes involved in running and cutting may be predisposed to these fractures [50]. Another study evaluated the gait patterns of runners and prospectively evaluated the incidence of lower limb overuse injuries. They confirmed that in the injured group the foot pronated less at the first metatarsal contact phase of the gait pattern, placing more pressure on the lateral border of the foot (as in a cavo-varus foot) compared to the uninjured group [20]. A Cochrane review in 1999 stated that ‘the use of shock absorbing inserts in footwear probably reduces the incidence of stress fractures in military personnel’ [40]. Another Cochrane review found gold standard evidence that custom-made foot orthoses were effective in the treatment of painful pes cavus [22]. Caution must however be used in directly translating these results to the professional athlete. Neutral-cushioned running shoes have
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recently been shown to statistically significantly reduce plantar pressure in athletes with cavus feet [46]. An association between proximal stress fractures of the second metatarsal and Achilles contracture was reported by Chuckpaiwong et al. They also found that over half of the patients with proximal second metatarsal stress fractures had a history of previous stress fracture or bilateral presentations [12]. In the first series of navicular stress fractures to be reported in athletes, Torg et al. [44] reported that 10 of the 21 involved limbs demonstrated limitation in dorsiflexion of the ankle, subtalar joint or both. In a small study of otherwise normal patients with midfoot and/or forefoot overuse symptoms, Di Giovanni et al. found significantly increased tightness in the gastrocnemius–soleus complex in the patient group compared with controls [13]. Specific stretching regimes have been shown to increase the range of ankle dorsiflexion in these patients [39] without leading to decreased power of plantar-flexion [29]. It appears possible therefore that relatively simple interventions, such as ensuring appropriate boots for the foot shape [30], providing insoles to players with cavus feet [30], customising insole designs to the movement patterns of specific playing positions [14] and stretching tight gastrocnemius–soleus complexes may lead to fewer overuse foot injuries and less recurrent injuries in athletes. 5. Conclusion In collision sports such as rugby, some injuries may be inevitable but clinicians should always be seeking ways to minimise their occurrence and impact. This study has revealed a high proportion of severity associated with chronic and overuse foot injuries in these professional athletes, which is even greater for recurrent presentations of those conditions. With greater attention paid to risk factors, some of these injuries and especially recurrences may be avoided. More sport specific, prospective studies are required to investigate the benefit of any interventions employed in this regard in elite athletes. Conflict of interest The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable on non-profit organisation with which the authors are affiliated. References [1] Alsop JC, Morrison L, Williams SM, Chalmers DJ, Simpson JC. Playing conditions, player preparation and rugby injury: a case–control study. Journal of Science and Medicine in Sport/Sports Medicine Australia 2005;8:171–80. [2] Armstrong 3rd DW, Rue JP, Wilckens JH, Frassica FJ. Stress fracture injury in young military men and women. Bone 2004;35:806–16. [3] Bathgate A, Best JP, Craig G, Jamieson M. A prospective study of injuries to elite Australian rugby union players. British Journal of Sports Medicine 2002;36:265–9 [discussion 9]. [4] Best JP, McIntosh AS, Savage TN. Rugby World Cup 2003 injury surveillance project. British Journal of Sports Medicine 2005;39:812–7. [5] Bird YN, Waller AE, Marshall SW, Alsop JC, Chalmers DJ, Gerrard DF. The New Zealand Rugby Injury and Performance Project. V. Epidemiology of a season of rugby injury. British Journal of Sports Medicine 1998;32:319–25. [6] Brooks JH, Fuller CW. The influence of methodological issues on the results and conclusions from epidemiological studies of sports injuries: illustrative examples. Sports Medicine (Auckland NZ) 2006;36:459–72. [7] Brooks JH, Fuller CW, Kemp SP, Reddin DB. An assessment of training volume in professional rugby union and its impact on the incidence, severity, and nature of match and training injuries. Journal of Sports Sciences 2008;26:863–73. [8] Brooks JH, Fuller CW, Kemp SP, Reddin DB. Epidemiology of injuries in English professional rugby union. Part 1. Match injuries. British Journal of Sports Medicine 2005;39:757–66.
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The epidemiology of foot injuries in professional rugby union players Christopher J. Pearce FRCS(Tr&Orth), MFSEM(UK)a,*, John H.M. Brooks PhDd, Simon P.T. Kemp MA, MBBS, FFSEM(UK&I)d, James D.F. Calder MD, FRCS(Tr&Orth), FFSEM(UK)b,c a
Trauma & Orthopaedic Dept, Royal Surrey County Hospital, Egerton Road, Guildford, Surrey, UK Trauma & Orthopaedic Dept, North Hampshire Hospital Foundation Trust, Aldermaston Road, Basingstoke, Hampshire, UK c Imperial College London School of Medicine, London, UK d Rugby Football Union, Twickenham, London, UK b
A R T I C L E I N F O
A B S T R A C T
Article history: Received 11 December 2009 Received in revised form 22 January 2010 Accepted 7 February 2010
Background: Foot injuries represent a small but important proportion of injuries to professional rugby union players. There are no detailed epidemiological studies regarding these injuries. The aim of this study was to describe the epidemiology of foot injuries sustained by a cohort of professional rugby union players and identify areas that may be targeted for injury prevention in the future. Methods: Medical personnel prospectively recorded injuries in professional Premiership rugby union players in England over four seasons. Injuries to the foot were identified and the time away from training and playing was reported. Results: A total of 147 foot injuries were sustained resulting in 3542 days of absence in total. Acute events accounted for 73% of all foot injuries, with chronic, mostly overuse conditions, accounting for 25% (undiagnosed 2%). Chronic conditions led to proportionately more time away from training and playing (p = <0.001). Specifically, stress fractures in the foot accounted for 8% of the total foot injuries but 22% of the absence. Navicular stress fractures had the longest recovery time with the mean return to training and match play of 188 days. Conclusion: In collision sports such as rugby, some injuries may be inevitable but clinicians should always be seeking ways to minimise their occurrence and impact. This study revealed a high proportion of morbidity associated with chronic and overuse foot injuries in these professional athletes. With greater attention paid to risk factors, some of these injuries, and importantly, recurrent injuries may be avoided. ß 2010 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.
Keywords: Rugby union Foot Injury Epidemiology
1. Introduction Rugby union is one of the most popular team collision sports in the world [24]. More than three million people in more than 100 countries across five continents play the sport annually [11]. In a questionnaire study involving over 17,000 adults between 1987 and 1990, rugby had the highest injury rate of all sports in the UK with 95.7 exercise related morbidity episodes reported per 1000 occasions of participation [34]. Injury rates increase with higher levels of play in many sports including rugby union [3,5,17,38,43]. Rugby union maintained amateur standing from the mid-19th century until after the World Cup in 1995. The injury rate in rugby appears to have increased considerably since the start of the professional era [3,17].
* Corresponding author at: 20 Topiary Square, Stanmore Road, Richmond, Surrey TW92DB, UK. Tel.: +44 (0)7976356076. E-mail address: [email protected] (C.J. Pearce).
Garraway et al. demonstrated this increase in injuries in both professional and amateur players since the game became professional at the top level [17]. Professional full-time training has resulted in increased player skill, strength, power and fitness as well as an increased mean body mass of the elite players [11]. Rule changes designed to create a more flowing game have meant that the ball-in-play time has increased considerably, for example; from 1603 s at the Rugby World Cup in 1995 to 1997 s in 2003 (a 25% increase) [11]. The lower limb is the most commonly injured anatomical region, accounting for approximately 42–59% of all injuries sustained at the elite level [3,8,9,23]. Foot injuries represent a small but important proportion of injuries to professional rugby union players [23], however, there are no detailed epidemiological studies regarding these injuries. The aim of this study was to describe the epidemiology and review the risk factors associated with foot injuries sustained by a cohort of professional rugby union players with a view to identifying potential future strategies for injury prevention.
1268-7731/$ – see front matter ß 2010 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.fas.2010.02.004
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114
2. Methods
3. Results
2.1. Injury assessment
The study involved a total of 33,340 h of match exposure (forwards: 17,758; backs: 15,583) and 395,223 h of training exposure (forwards: 223,096; backs: 172,127). During this period 147 foot injuries were sustained resulting in 3542 days of absence. Table 1 gives an overview of the number and severity of foot injuries sustained by forwards and backs during training and match play. Overall, foot injuries accounted for 4% of all the injuries recorded and led to 5% of the absence from playing and training. The incidence of foot injuries sustained during match play was significantly higher than the incidence during training (3.3 compared with 0.09 injuries per 1000 player-hours [95% CI, 2.7– 4.0 and 0.07–0.13]) (p < 0.001). There was no difference between forwards and backs in terms of foot injury incidence during match play with both sets of players sustaining 3.3 injuries per 1000 player-hours [95% CI, 2.5–4.2]. Backs sustained more injuries than forwards in training (0.12 compared with 0.08 injuries per 1000 player-hours [95% CI, 0.07–0.18 and 0.05–0.12]) but this was not statistically significant (p = 0.20). The mean severity of each foot injury was 24 days absence (95% CI, 19–28) (match: 27 [95% CI, 22–23]; training: 16 [95% CI, 11– 21]). The mean severity of injuries was higher for forwards in matches than for backs (31 compared with 23 [95% CI, 22–40 and 17–30]). However the mean severity of training injuries was higher for backs than for forwards (backs: 18 [95% CI, 11–27]; forwards: 13 [95% CI, 8–21]). These differences were not significant (p = 0.13 and 0.37, respectively). The total days absence due to match foot injuries was 89 per 1000 player-hours [95% CI, 74–107] while for training injuries it was 1.5 per 1000 player-hours [95% CI, 1.1–2.0] (p < 0.001). There was no statistical difference between forwards and backs in terms of days absence due to foot injuries sustained during matches (forwards, 100 [95% CI, 77–129]; backs, 77 [95% CI, 58–100] (p = 0.16)). However backs lost significantly more days in total due to training foot injuries than forwards (backs, 2.0 [95% CI, 1.3–3.2]; forwards, 1.0 [95% CI, 1.1–2.0] (p = 0.03)), although the total number of days lost were very small. There were no significant differences in the overall incidence and average severity of foot injuries sustained during matches for forwards or backs as a function of player’s playing position (Table 2) or body mass (Tables 3 and 4) except for backs of body mass between 85 and 99.9 kg who had a significantly lower average severity of foot injuries (Table 4).
A prospective study was performed involving a male cohort of 899 professional rugby union players consisting of 488 forwards and 411 backs from 14 English Premiership Rugby Union clubs over 4 seasons (2002–2004 and 2005–2007). The main survey methods have been described previously [8,9] and were compliant with the consensus statement on injury definitions and data collection procedures for studies of injuries in rugby union [15,16]. All players were members of the clubs’ firstteam squad and were professional rugby players. Only six eligible players refused to take part, and the rest gave their written consent to be included. The ethics committee deemed that ethics approval was not required because the study did not involve hospital patients or any invasive procedures on the participants. The time-loss injury definition used was as follows: ‘‘any injury to the foot that prevents a player from taking full part in all training and match play activities planned for that day, for a period of 24 h from midnight at the end of the day that the injury was sustained.’’ Individual match exposure (number of player-hours) was recorded for each player, and team fitness coaches recorded volume of training exposure on a weekly basis. Medical personnel including both physiotherapists and physicians affiliated with the clubs prospectively recorded all injuries to the players in England over the four seasons. Injuries to the foot were identified and the time away from training and playing was recorded and reported. Foot injuries were classified according to a modified Orchard Sports Injury Classification System [35]. A standard injury form was completed in which associated injury detail was provided. The foot injuries were diagnosed by clinical examination, radiographs, ultrasound scan, MRI scan, or a combination of these. Recurrence of an injury was diagnosed by the medical personnel affiliated with the club using their clinical judgement that it was the same injury in the same location as previously. 2.2. Data analysis The incidence rate was defined as the number of injuries per 1000 player-hours of match exposure for match injuries or injuries per 1000 player-hours of training for training injuries. Injury severity was defined as the number of days taken to return to full fitness. Full fitness was defined as the player being able to take full part in the training activities planned for that day and be available for match selection. Statistical analysis was performed using Microsoft Office Excel 2007. A Z-test, utilizing the standard deviation of the study population as a whole, was used to identify significant differences in the number of injuries and severity of those injuries between the categorical groups. Statistical significance was accepted if p < 0.05.
3.1. Acute and chronic injuries Table 5 shows all of the foot injury categories with their proportions in terms of incidence and severity as well as the average severity and total absence for each injury. Acute events accounted for 73% of all foot injuries, with chronic, mostly overuse conditions, accounting for 25% and the other 2% made up of undiagnosed foot pain resulting in absence from training and matches.
Table 1 Number and severity of foot injuries. Match injuries
Forwards Backs All players
Training injuries
All injuries
Number of injuries
Average severity (days)
Total absence (days)
Number of injuries
Average severity (days)
Total absence (days)
Number of injuries
Average severity (days)
Total absence (days)
58 52 110
31 23 27
1774 1193 2967
17 20 37
13 18 16
223 352 575
75 72 147
27 21 24
1997 1545 3542
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Table 2 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries as a function of playing position. Playing position
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
Front-row (reference) Second-row Back-row Inside backs Midfield backs Outside backs
2.63 3.18 3.04 3.19 1.74 3.29
* 1.21 1.16 1.21 0.66 1.25
* 0.60 0.67 0.60 0.37 0.50
25 30 35 29 16 22
* 1.21 1.41 1.15 0.65 0.89
* 0.61 0.32 0.70 0.34 0.73
(1.61–4.29) (1.85–5.48) (1.91–4.82) (1.85–5.49) (0.83–3.66) (2.12–5.10)
(0.58–2.52) (0.59–2.27) (0.58–2.53) (0.27–1.61) (0.65–2.42)
(15–41) (18–52) (22–56) (17–49) (8–34) (14–34)
(0.58–2.51) (0.72–2.76) (0.55–2.39) (0.27–1.57) (0.46–1.72)
Table 3 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries for forwards as a function of body mass. Body mass (kg)
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
85–99.9 (reference) 100–114.9 115–135
1.84 (0.59–5.72) 3.52 (2.53–4.91) 2.16 (1.16–4.02)
* 1.91 (0.59–6.21) 1.17 (0.32–4.26)
* 0.28 0.81
63 (20–196) 26 (19–36) 34 (18–63)
* 0.41 (0.13–1.32) 0.54 (0.15–1.95)
* 0.14 0.34
Table 4 The incidence (injuries/1000 player match-hours) and average severity (days) of match injuries for backs as a function of body mass. Body mass (kg)
Incidence (95% CI)
Incidence ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Average severity ratio (95% CI)
p (Z-test)
70–84.9 (reference) 85–99.9 100–114.9
3.63 (1.89–6.97) 2.21 (1.45–3.35) 4.34 (2.07–9.10)
* 0.61 (0.28–1.32) 1.20 (0.45–3.21)
* 0.21 0.73
40 (21–78) 15 (10–22) 31 (15–66)
* 0.36 (0.17–0.79) 0.78 (0.29–2.08)
* 0.01 0.62
There were significantly more acute foot injuries (2.5 injuries per 1000 player-hours [95% CI, 2.0–3.1]) than chronic injuries (0.7 injuries per 1000 player-hours [95% CI, 0.5–1.1]) diagnosed during match play (p < 0.001). This trend was also seen in injuries diagnosed during training (acute, 0.06 [95% CI, 0.04–0.09]; chronic, 0.03 [95% CI, 0.02–0.06]) but it was not statistically significant (p = 0.08). Chronic conditions sustained in both matches and training however had a significantly higher mean severity (Table 6). Consequently chronic foot injuries resulted in proportionately more time away from training and playing (45%), compared with the number of chronic injuries (25%). A specific example is that of stress fractures in the foot which only accounted for 8% of the total foot injuries but 22% of the absence (Table 2). Navicular stress fractures had the longest recovery time with a mean return to training and match play of 188 days. 3.2. Recurrent absence due to overuse injuries Fig. 1 shows the proportion of newly diagnosed and recurrent injuries in this series. There were over twice as many newly
Fig. 1. Graph showing proportion of newly diagnosed and recurrent injuries.
diagnosed chronic and overuse injuries as recurrences of a previously diagnosed chronic condition. The mean recovery time from recurrent chronic conditions, however was 99 days [95% CI, 49–198], significantly higher than 28 days [95% CI, 19–41] for the newly diagnosed chronic injuries (severity ratio 3.5 [95% CI, 1.6– 7.7] (p < 0.02)). 4. Discussion Comparing the results of different studies on rugby injuries requires some caution as injury definitions (time loss, missed matches, diagnostic assessment and surgery), the definition of recurrent injury, methods of reporting injuries (number, proportions and incidence) and the method of calculating incidence (injuries per 1000 player-hours, per 1000 athlete-exposures and per 1000 matches) differ [6]. Consequently proportions are often used when comparing studies. In the current study, foot injuries represented 4% all injuries sustained, similar to the proportion found another study of a similar group of players in the professional era [3]. Difficulties with inter-study foot injury incidence comparisons are compounded by the fact that studies often group foot and ankle injuries together [4,17], while others group foot injuries into ‘other’ injuries [5]. It is possible, however, that there has been an increase in the proportion of foot injuries sustained in the professional era compared to injuries to other parts of the body. A survey of 356 rugby union players enrolled in the Rugby Injury and Performance Project cohort in New Zealand in 1993 revealed that the foot only accounted for 1% of all the injuries reported [19] compared with 4% in the current study. There are many potential confounding factors but this does raise the possibility that the higher profile injuries, such as knee and shoulder injuries have, perhaps rightly, been more successfully targeted for injury prevention than those of the foot. Previous epidemiological studies of injuries sustained in rugby union have concentrated on risk factors such as playing position, the period of the match and/or season in which the injury was
C.J. Pearce et al. / Foot and Ankle Surgery 17 (2011) 113–118
116 Table 5 Injury diagnosis. Injury category
Injury diagnosis
Number of injuries
Acute fracture
Cuboid acute fracture Cuneiform acute fracture Fourth metatarsal acute fracture Fractured metatarsal(s) Fractured phalanx (foot) Multiple metatarsal fractures Navicular acute fracture Second metatarsal acute fracture
Proportion of foot injuries
Average severity
Days absence
Proportion of foot injuries absence
1 1 2 2 4 1 2 1
1% 1% 1% 1% 3% 1% 1% 1%
35 37 8 51 21 134 48 82
35 37 15 101 83 134 95 82
1% 1% 0% 3% 2% 4% 3% 2%
Dislocated joint(s) of foot (incl. Lisfranc injury) Foot ligament sprain (including spring ligament) Interphalangeal ligament disruption Ruptured volar plate first MTP joint Sprain foot joint Sprained toe/turf toe
14 1 9 2 1 29 16
10% 1% 6% 1% 1% 20% 11%
42 7 10 22 89 18 22
582 7 87 44 89 534 352
16% 0% 2% 1% 3% 15% 10%
Foot blistering Foot haematoma Foot laceration Foot muscle strain Heel fat pad bruise Toenail problem/haematoma
58 2 21 1 3 6 2
39% 1% 14% 1% 2% 4% 1%
19 4 8 8 7 4 3
1113 7 166 8 22 25 5
31% 0% 5% 0% 1% 1% 0%
Cuboid stress fracture Fifth metatarsal stress fracture Navicular stress fracture Second metatarsal stress fracture Sesamoid stress fracture Stress fracture metatarsal Stress fracture midtarsal bone (navicular, cuneiform, cuboid) Third metatarsal stress fracture
35 1 2 2 1 3 1 1 1
24% 1% 1% 1% 1% 2% 1% 1% 1%
7 16 60 188 55 39 27 8 54
233 16 119 375 55 118 27 8 54
7% 0% 3% 11% 2% 3% 1% 0% 2%
First metatarsophalangeal joint degenerative arthritis Symptomatic accessory bone of foot
12 1 1
8% 1% 1%
772 2 99
64 2 99
22% 0% 3%
2 2 1 7
1% 1% 1% 5%
101 13 53 50
51 26 53 347
3% 1% 1% 10%
All chronic forefoot disorders Chronic soft-tissue disorder Cuboid syndrome or foot peroneal tendonitis Distal plantar fascitis Plantar fascitis/strain/calcaneal spur Tibialis posterior insertion tendonitis
10 4 1 7 1
7% 3% 1% 5% 1%
426 17 2 29 12
43 66 2 204 12
12% 2% 0% 6% 0%
All chronic soft-tissue disorders Foot pain undiagnosed Foot pain undiagnosed
13 3
9% 2%
284 10
22 31
8% 1%
All acute fractures Acute joint injury
All acute joint injuries Acute soft-tissue injury
All acute soft-tissue injuries Stress fracture
All stress fractures Chronic joint disorder
All chronic joint disorders Chronic forefoot disorder
Metatarsalgia Mortons neuroma or Joplins neuritis Sesamoiditis/first metatarsophalangeal joint pain
All foot pain undiagnosed All foot injuries
sustained, training volume and the phase of play [3,5,7– 10,17,19,23,41,43]. No study has so far differentiated between the chronic, overuse injuries and the acute injuries, probably partly because it is less relevant in other areas of the body than in the foot. Even studies which have evaluated the state of the pitch (e.g. playing on hard ground) with regard to injury rates have not made this distinction [1,28,42].
3
2%
31
10
1%
147
100%
24
3542
100%
The majority of investigations into overuse injuries in athletes have involved runners, where these types of injury predominate. There can be no doubt that the volume and intensity of training play a major contributory role [26,27,31,47]. In a study of training volumes in professional rugby, an increase in the average number of training injuries and the average number of days lost per team per week was seen when higher training volumes were performed.
Table 6 Average severity (days) of chronic and acute injuries. Match injuries
Chronic Acute
Training injuries
All injuries
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
Average severity (95% CI)
Severity ratio (95% CI)
p (Z-test)
52 (35–77) 20 (16–25)
2.5 (1.6–4.0) Ref
<0.001 Ref
26 (15–45) 10 (7–14)
2.7 (1.4–5.3) Ref
0.004 Ref
43 (31–59) 18 (15–22)
2.4 (1.6–3.5) Ref
<0.001 Ref
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The most common training injury locations in this study again were to the lower limb [7]. With the greater exposure to training and playing involved in professional rugby union we should expect to see a greater incidence of, and absence due to, overuse conditions including stress fractures. Previous reports have stated that stress fractures account for up to 10% of sports overuse injuries [27,33]. In this series of rugby union professionals, stress fractures accounted for 8.2% of all injuries to the foot and 32% of the chronic foot injuries. The current study found that chronic/overuse injuries to the foot led to a disproportionate period of absence from training and playing than acute injuries. In fact, a navicular stress fracture is second only to an ACL rupture as the injury with the greatest mean severity in professional rugby [8,9]. Tarsal stress fractures have been shown by other investigators to take the longest of all stress fractures to recover from [32]. It is important to make the distinction between acute and chronic injuries because, while some acute injuries may be inevitable in a collision sport such as rugby, chronic conditions should be more easily targeted for injury prevention strategies. Additionally, club physiotherapists, physicians and the players themselves are in a better position to instigate injury prevention measures for an overuse injury than an acute injury as acute injury prevention is influenced more strongly by the laws of the game which are typically out of their direct control. Another reason to concentrate attention on the chronic and overuse conditions as, highlighted by this study, is that recurrent absence due to an injury of this type takes up to four times longer to recover from than a new presentation. Club medical staff need to be extra vigilant to avoid incomplete treatment and thoroughly investigate and treat any contributory factors in these players. Many intrinsic and extrinsic risk factors for the development of stress fractures in athletes have been reported, some with more relevance to professional rugby than others [2,12,18,21,27,32, 33,37,45]. The subtle cavo-varus foot in the athlete has long been recognised [44], and has recently been gaining more attention as being a significant risk factor for various overuse conditions and especially stress fractures and recurrent stress fractures [25,27,30]. This foot shape is known to be relatively rigid with a poor capacity for shock attenuation and increased initial peak forces have been recorded in runners with high arches [46,48,49]. Most of the work measuring the forces acting on feet has concentrated on running in a straight line, however one study has shown that these forces are significantly increased during cutting, jumping and landing, all of which feature frequently in rugby. Different athletic shoes afforded various levels of protection from these forces [36]. Similar findings have also been reported in soccer [14]. Wright et al. reported that patients with Jones fractures (basal 5th metatarsal) had a twofold increase in peak pressures at the base of the fifth metatarsal head compared to a control group and that athletes involved in running and cutting may be predisposed to these fractures [50]. Another study evaluated the gait patterns of runners and prospectively evaluated the incidence of lower limb overuse injuries. They confirmed that in the injured group the foot pronated less at the first metatarsal contact phase of the gait pattern, placing more pressure on the lateral border of the foot (as in a cavo-varus foot) compared to the uninjured group [20]. A Cochrane review in 1999 stated that ‘the use of shock absorbing inserts in footwear probably reduces the incidence of stress fractures in military personnel’ [40]. Another Cochrane review found gold standard evidence that custom-made foot orthoses were effective in the treatment of painful pes cavus [22]. Caution must however be used in directly translating these results to the professional athlete. Neutral-cushioned running shoes have
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recently been shown to statistically significantly reduce plantar pressure in athletes with cavus feet [46]. An association between proximal stress fractures of the second metatarsal and Achilles contracture was reported by Chuckpaiwong et al. They also found that over half of the patients with proximal second metatarsal stress fractures had a history of previous stress fracture or bilateral presentations [12]. In the first series of navicular stress fractures to be reported in athletes, Torg et al. [44] reported that 10 of the 21 involved limbs demonstrated limitation in dorsiflexion of the ankle, subtalar joint or both. In a small study of otherwise normal patients with midfoot and/or forefoot overuse symptoms, Di Giovanni et al. found significantly increased tightness in the gastrocnemius–soleus complex in the patient group compared with controls [13]. Specific stretching regimes have been shown to increase the range of ankle dorsiflexion in these patients [39] without leading to decreased power of plantar-flexion [29]. It appears possible therefore that relatively simple interventions, such as ensuring appropriate boots for the foot shape [30], providing insoles to players with cavus feet [30], customising insole designs to the movement patterns of specific playing positions [14] and stretching tight gastrocnemius–soleus complexes may lead to fewer overuse foot injuries and less recurrent injuries in athletes. 5. Conclusion In collision sports such as rugby, some injuries may be inevitable but clinicians should always be seeking ways to minimise their occurrence and impact. This study has revealed a high proportion of severity associated with chronic and overuse foot injuries in these professional athletes, which is even greater for recurrent presentations of those conditions. With greater attention paid to risk factors, some of these injuries and especially recurrences may be avoided. More sport specific, prospective studies are required to investigate the benefit of any interventions employed in this regard in elite athletes. Conflict of interest The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable on non-profit organisation with which the authors are affiliated. References [1] Alsop JC, Morrison L, Williams SM, Chalmers DJ, Simpson JC. Playing conditions, player preparation and rugby injury: a case–control study. Journal of Science and Medicine in Sport/Sports Medicine Australia 2005;8:171–80. [2] Armstrong 3rd DW, Rue JP, Wilckens JH, Frassica FJ. Stress fracture injury in young military men and women. Bone 2004;35:806–16. [3] Bathgate A, Best JP, Craig G, Jamieson M. A prospective study of injuries to elite Australian rugby union players. British Journal of Sports Medicine 2002;36:265–9 [discussion 9]. [4] Best JP, McIntosh AS, Savage TN. Rugby World Cup 2003 injury surveillance project. British Journal of Sports Medicine 2005;39:812–7. [5] Bird YN, Waller AE, Marshall SW, Alsop JC, Chalmers DJ, Gerrard DF. The New Zealand Rugby Injury and Performance Project. V. Epidemiology of a season of rugby injury. British Journal of Sports Medicine 1998;32:319–25. [6] Brooks JH, Fuller CW. The influence of methodological issues on the results and conclusions from epidemiological studies of sports injuries: illustrative examples. Sports Medicine (Auckland NZ) 2006;36:459–72. [7] Brooks JH, Fuller CW, Kemp SP, Reddin DB. An assessment of training volume in professional rugby union and its impact on the incidence, severity, and nature of match and training injuries. Journal of Sports Sciences 2008;26:863–73. [8] Brooks JH, Fuller CW, Kemp SP, Reddin DB. Epidemiology of injuries in English professional rugby union. Part 1. Match injuries. British Journal of Sports Medicine 2005;39:757–66.
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