Surveillance of injuries among Kenya Rugby Union (KRU) players — Season 2010
Authors: Muma N1 MBChB, MMed, Saidi H2 MBChB, MMed, FACS, Githaiga3 JW MBChB, MMed
Affiliation: 1- Kijabe Hospital, Kenya 2- Department Human Anatomy, University of Nairobi 3- Department of Surgery, University of
Nairobi. Correspondence: Dr. Muma Nyagetuba; Kijabe Hospital, Kenya Email
Objective: To determine the incidence and characteristics of injury amongst Kenya rugby union players and associated factors.
Design: A whole population prospective cohort study.
Methods: 364 registered Kenya rugby union (KRU) players were stud-ied throughout the 2010 season. Data on their demographics, injury incidence, pattern and severity were gathered. The study tool used was the Rugby International Consensus Group (RICG) Statement.
Results: There were 173 backs and 191 forwards. One hundred and two 1 injuries for 60 league games (2400match player hours) were recorded. The incidence of injuries was 42.5/1000 match player hours (mph), (44.2 for forwards and 40.8 for backs). Lower limb injuries were the most common (41.2%) . Players were most prone to injuries in the in tackle scenario (63.7%), at the beginning of the season (47.1%), and in the last quarter (50%) of a game.
Conclusion: The injury incidence recorded contrast the earlier Kenyan data but is comparable to international amateur level incidence, uniqueness of the Kenyan environment notwithstanding. The higher rates associated with the tackle/tackled scenario, earlier part of the season and later part of the game, suggest interventions can target player conditioning, and use of protective gear.
Rugby is a high velocity and collision sport attended by one of the highest rates of injuries in team sports (1-3). As is the trend in the global scene, rugby is increasingly a popular sport in Kenya. Competition is higher, the game faster and the players stronger. The combination of fac-tors is fodder for rising rates of injury (1-7) with signifi-cant impact on player and team performance. 'prevention is better than cure’ approach to rugby in-jury is made possible by understanding the characteris-tics and magnitude of the problem. An earlier Kenyan study suggested comparatively higher rates of rugby re-lated injuries but did not establish models of relation-ships with risk factors (8). Internal and external factors shown to influence the outcome of injury include player fitness, part of the season, phase of play, player position, state of the pitch and player physique (9-14). Accord-ing to Brooks for example, injuries that cause the most significant absence from the field of play for forwards and backs are anterior cruciate ligament and hamstring injury respectively (6).
This paper explores the injury experience and the asso-ciated risk profile during the Kenya 2010 15-side rugby season.
The prospective whole population cohort study of 364 players was conducted in the 2010 15-aside season. It comprised of the Kenya cup (KC) division one and Eric Shirley shield (ESS) division two leagues. All players were KRU registered and had to be above 18years of age. The clinical officers in charge of data collection were trained for two weeks to use the instrument of data col-lection followed by a proficiency exam using preseason matches.
Blood bin injuries defined by Law 3.11(a) of International Rugby Board ( IRB) were excluded unless a training session or match was subsequently missed because of the said injury. Age, height, weight, injury status at that time and posi-tion played were documented preseason. The players were clustered into forwards (positions 1 to 8) and backs (positions 9 to 15).
Data analysis was performed using SPSS version 17 soft-ware. Incidence was calculated as injuries per 1000 match player hours (mph) (95% CI). Student t-test was used to compare the means between injured and non-injured for continuous vari- ables i.e. age, weight, height, BMI. Match exposure was calculated on the basis of 15 players (8 forwards, 7 backs) per team exposed for 80 minutes (first half 0-20, 20-40, second half 40-60, 60-80minutes). Approval for study was obtained from the Kenyat-ta National Hospital Ethics and Research Committee and the KRU board.
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Players enrolled in the study were 169 (76 backs and 93 forwards) for KC and 195 (97 backs 98 forwards) for ESS. The 30 KC and 30 ESS games played constituted a total 2400 mph. The season lasted 4 months during which 102 injuries were recorded. The incidence of injuries was 42.50/1000mph (Forwards 44.17; Backs 40.83). The ages of the players ranged from 18 to 40 years with a mean of 22.80 years (SD 3.724). The mean weight was 81.83kg (SD12.57) with a mean height of 1.75metres (SD 0.70) and a mean BMI of 26.59(SD 3.73). KC accounted for 64.6% of injuries which translated to an incidence of 55 injuries/1000mph and 30 injuries /1000mph for the ESS (p<0.0001). There was no career ending injury.
Anthropometry in relation to level of play
The Kenyan player’s mean age was 22.80 years (SD 3.724) with a mean weight of 81.83kg (SD12.57) and mean height of 1.75(SD 0.70).
The KC player was older (p <0.001), heavier (p <0.001) and taller (p0.002) (Table 1).
Anthropometry between injured and non-injured
The 102 injuries occurred amongst 92 players. The in-jured player was older (p 0.046), heavier (p 0.014), taller (p 0.004), and with a larger BMI (p 0.271), (Table 2).
Distribution of injury based on location of body
The forwards had an injury incidence of 44.17injuries per 1000mph compared to 40.83 injuries per 1000mph for the backs (p 0.52). The most common regions injured were the lower limb (41.2%), upper limb (24.6%) and head and neck (26.4%). The most common types of injuries were ligamentous (38.2%) and concussion (8.9%) (table4). The types of injuries were generally of similar amongst the forwards and backs. (Table 3)being linked with dangerous play.A player in KC had higher overall risk to injury as compared ESS, odds ratio 2.18 (p 0.006).
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Distribution of injuries based on mechanism of injury
Majority of the injuries, 94.9% were a result of contact. The tackling/tackled scenario with a cumulative inci-dence of 63.7%, accounted for a majority of incidences in mechanism of injury. The line out and the maul ac-counted for the list incidence. (Figure 2)
Distribution of injury as a factor of time
The first quarter of the season had 47.1% of injuries, doubling any other quarter in the season. The frequency of injuries was highest in the first half of the season with a cumulative of 69.6%. (Table 5) Most injuries occurred in the last quarter of the game, and a total 73.5% of injuries occurring in the extreme quarters of the game. The proportion of injuries associated with foul play and dangerous play was 11.6% and 10.78%
The purpose of this study was to report the incidence of injury and associated factors in amateur rugby in Kenya. Injury incidence was 42.50 injuries per 1000mph. The Kenyan players were younger and lighter in weight when compared to players in professional leagues (9). This result is consistent with previous data that depict that bigger body sizes are associated with higher rates of injuries (9, 15). Compared to Kenya Cup (K), Eric Shir-ley Shield (ESS) players were smaller and younger. With a less stringent age of inclusion criteria; the differences may have been more dramatic. Our overall injury incidence is consistent with armature level play. It is however one third that reported in the earlier Kenyan study (8). We contend that the discrep-ancy is occasioned by the exclusion of minor injuries including blood bin injuries (8).
The tackle/tackling scenario was responsible for the high-est injury incidence, as previously reported (7,9,16,17). In the present study however, most injuries afflicted the tackler contrasting recent trends. An entry point for pre-vention would be the acquisition of protective gear and coaching of skillful tackling techniques (9, 18).Most in-juries occurred in the first quarter of the season. Similar results previously have ascribed this to preseason condi-tioning (12, 14). Coaches and fitness instructors invest time and resources in player fitness acquisition and early rehabilitation for the injured to mitigate against early season injuries (14).
Corroborating earlier studies (1,10,15), the results of the present study further show that approximately 50% of injuries occurred in the last quarter of the game, pos-sibly due to fatigue, reduced self-awareness and protection (3,8,9). Therefore, improving player endurance and conditioning might aid.
The incidence and pattern of injuries was similar between forwards and backs and consistent with other reported data (9). The result on
anatomical regions involved echoes previous reports (5, 9, 17). The head, shoulder and ankle were the most vulnerable to injury, probably related to exposure and involvement in most phases of contact. There are data to show that injuries occasioned by exposure and
involvement of the head can be prevented by use of head gear (19,20). Muscle strengthening exercises and use of shoulder pads can
reduce shoulder injuries (20). Ankle injuries on the other hand are possibly exacerbated by poor pitch conditions, a relationship not explored
in this study. Pre-match warming and conditioning would limit the ligamentous strains and muscle pulls which were common in these regions (1, 9).
The degree of foul play involvement was low (2). This was laudable and probably a pointer to the stringent measures by the IRB to counter
foul play. In conclusion, the study has provided benchmark val-ues for the injury incidence and characteristics in Kenya. The injury rate recorded is much lower than previously documented.
Acknowledgements go to the medical director KRU who coordinated club level participation, the entire KRU for the cooperation and Dr. Onyuma the study stat-istician. The study was fully funded by the authors. There was no source of external funding. There is no competing or conflict of interest by any of the authors.
Junge A, Cheung K, Edwards T et al. Comparison of incidence and Injuries in youth amateur soccer and rugby Br J Sports Med 2004; 38: 168-172.
Doris W and Browne C. Injury to rugby and association football Br J Sports Med 1974; 8: 183-187.
Nicholl J P, Coleman P, Williams B T, et al. The epidemiology of sports and exercise related injury in the United Kingdom. Br J Sports Med 1995; 29:232–8.
Jakoet I, Noakes T D. A high rate of injury during the 1995 Rugby World Cup. S Afr Med J 1998; 88: 45–7.
Best J P, McIntosh A S, and Savage T N. Rugby World Cup 2003 injury surveillance project. Br J Sports Med 2005; 39: 812–817.
Brooks J H M, Fuller C W, Kemp S P T, et al. A prospective study of injuries and training amongst the England 2003 Rugby World Cup squad. Br J Sports Med 2005; 39: 288–93.
Holtzhausen L J, Schwellnus M P, Jakoet I, et al. The inci-dence and nature of injuries in South African rugby players in the rugby Super 12 competition. S Afr Med J 2006; 96: 1260–5.
Wekesa M, Asembo J M, Njororai W S. Injury surveillance in a rugby tournament. Br J Sports Med 1996; 30: 61–3.
Fuller C W, Laborde F, Weather R J, et al. International Rugby Board rugby world cup 2007 injury surveillance study. Br J Sports Med 2008; 42: 452-459.
Gérard D F, Waller A E and Bird Y N. The New Zealand Rugby Injury and Performance Project: II. Previous injury experi-ence of a rugby-playing cohort. Br J Sports Med 1994; 28: 229-233.
Gabbett T J. Incidence, site, and nature of injuries in amateur rugby league over three consecutive seasons. Br J Sports Med 2000; 34:98–103.
Bird Y N, Waller S W, Marshall S W, et al. The New Zealand rugby injury and performance project. V. Epidemiology of a season of rugby union. Br J Sports Med 1998; 32: 319–25.
Lee A J, Garraway W M. Epidemiological comparison of in-juries in school and senior club rugby. Br J Sports Med 1996; 30: 213–17.
Lee A J, Garraway W M and Arneil D W.Influence of pre- season training, fitness, and existing injury on subsequent rugby injury. Br J Sports Med 2001; 35: 412-417.
Bathgate A, Best J P, Craig G, et al. A prospective study of in-juries to elite Australian rugby union players. Br J Sports Med 2002; 36: 265–9.
Fuller C W, Molloy M G, Bathgate C, et al. Consensus state-ment on injury definitions and data collection procedures for studies of injuries in rugby union. Br J Sports Med 2007; 41: 328–31.
Brooks J H M, Fuller C W, and Kemp S P T et al Epidemiol- ogy of injuries in English professional rugby union: match injuries. Br J Sports Med 2005; 39: 767–75.
Gabbett T J. Incidence, site, and nature of injuries in amateur rugby league over three consecutive seasons. Br J Sports Med 2000; 34: 98–103.
International Rugby Board(2006) viewed January 27th 2010 www.irb.com
Gerrald D F. The use of padding in rugby union. Br J Sports Med 1998; 25: 329–32.