Rugby union is a truly international sport, which ranks second in participation only to soccer as a form of ‘football’. Unfortunately, rates of injury are high in rugby union, sometimes averaging as many as two serious injuries per game, and there is evidence that injury rates are increasing rather than ameliorating (‘A Prospective Survey of Injuries to First-Grade Rugby Union Players’. Clin J Sports Med, Vol. 4, pp. 249-256, 1994.) What can be done to stop the acceleration of RU injuries and to bring down the total number of injuries occurring per season? To find out, researchers from the Eastern Suburbs Sports Medicine Centre in Sydney and the Australian Rugby Union kept detailed medical records on all Australian Wallabies players from 1994 through 2000 (‘A Prospective Study of Injuries to Elite Australian Rugby Union Players.’ British Journal of Sports Medicine, Vol. 36, pp. 265-269, 2002); the Wallabies are a national side which has garnered two Rugby World Cup victories (1991 and 1999). During the seven-year period, all injuries were recorded, with an injury defined as an incident which caused a player to either leave the field or miss a subsequent game. Injury severity was classified as mild, moderate, or severe, with mild injuries causing a player to miss one game, moderate injuries producing two to three missed games, and severe injuries causing a player to miss more than three games. Injuries were classified according to the site of injury, the position of the injured player, the mechanism of injury, type of injury, time and place of injury, whether the injury was acute or chronic, and of course the severity of damage.
During the period between 1994 and 2000, the Wallabies played 73 Test matches, 13 non-Test matches, and five Australia ‘A’ matches (91 games in all), and the total time spent playing added up to about 1820 hours. 82 players participated in play during the seven seasons of study, and there were 143 injuries, with 126 occurring during games and 17 during practice. This represented a rather modest injury rate of 69 injuries per 1000 player hours of game play, or .09 injuries per player per game. Note that the rate of injury per game, however, was 126/91 or 1.4. Thus, every match could be expected to produce at least one serious injury resulting in lost competition time.
As it turned out, the locks were the most-injured players, followed by the number 8, and the number 10 was the most injured back. Halfbacks were in the driver’s seat when it came to injuries, with the lowest rate for all positions. In general, injuries were slightly skewed towards forwards, who comprised 53% of the players but suffered 59% of the injuries; backs, who comprised 47% of the players, experienced 41% of the total damage.
As you might expect, the head was the most commonly injured body site; in fact, head injuries added up to 25% of all injuries. 75% of the head injuries were lacerations, while 19% were concussions (there were seven total concussions, or one per year), and 6% (two) were fractures. The next most-injured body sites were the knee (14% of all injuries), thigh (14% of injuries), and ankle (11%). The knee turned out to be the most common site of severe injuries, chalking up 25% of all severe damages; in fact, 40% of knee injuries could be classified as severe, with half of these being medial collateral ligament tears. The hand/finger and shoulder ran close seconds to the knee in terms of severe damage, with fractures of the finger and shoulder dislocations being fairly common. Half of the thigh injuries were hamstring strains or tears.
Breaking the rugby-union players’ bodies down into regions, the lower limb was the most commonly injured area, with 52% of all injuries. The head and neck followed with 29%, and the upper limb settled at 15%; the trunk and ribs were seldom damaged.
Tackling was by far the most dangerous element in rugby-union play; the act of either tackling or being tackled was associated with 59% of all injuries – and 66% of the severe injuries. ‘Open play’ – when the ball is no longer in a set piece, in a ruck or maul, or in the tackle – accounted for about 20% of injuries (and 19% of severe injuries), while good-old ruck or maul added 15%. Interestingly enough, the set pieces (scrums and line-outs) were relatively safe, accounting for just 2% of all injuries, with no injuries recorded in the line outs at all. Foul play produced 3.5% of the injuries observed.
An extremely interesting finding was that 69% of injuries occurred during the second halves of games, while just 31% took place in the first halves. In addition, the third quarter was by far the most dangerous part of the game, reserving 40% of all injuries versus 29% for the fourth quarter, 24% for the second, and a gentle 7% in the first.
One might expect that more experienced players would be less prone to injury than relatively inexperienced and less skilled players, but injury rates in rugby union actually tend to increase with the grade of play (‘Tackling Rugby Injuries’. Lancet, Vol. 345, pp. 1452-1453, 1995). The Wallabies, for example, who are among the best players in Australian Rugby Union, were injured at a rate of 69 injuries per 1000 playing hours. In contrast, other studies which used similar definitions for injuries but which tracked male recreational – not professional – rugby players identified injury rates as low as 14 injuries per 1000 playing hours and no higher than 53 injuries per 1000 hours. In addition, school-boy injury rates are thought to be much lower, dropping to seven injuries per 1000 hours in some research and peaking at no higher than 27.5 per 1000 hours in other analyses. Recently, a study of senior female rugby players was completed which detected an injury rate of 20.5 per 1000 game hours (‘The Epidemiology of Women’s Rugby Injuries’. Clin J Sports Med, Vol. 9, pp. 75-78, 1999).
These findings are more than just numbers; they contain important clues about how to reduce rugby union injury rates. Take, for example, the observation that injuries are much more likely to occur during the second halves of games. No doubt fatigue is a factor here; as muscular fatigue increases, muscular force output drops, and the muscles do a poorer job of protecting themselves and associated connective tissues, including tendons, ligaments, and bones. Coordination is also lost as fatigue mounts, leading to poorly controlled tackles and thus a greater risk of getting hurt. Rugby union players can reduce second-half muscular and mental fatigue, of course, by upgrading their overall aerobic fitness; in addition to working on their strength and quickness during training, they should also be concerned about variables such as VO2max, lactate threshold, and movement efficiency. Since the second-half injuries tend to fall more frequently in the third quarter than the fourth, there is also a suggestion that improper warm-up following halftime may contribute to the high second-half injury rate. Warm-ups might decrease the risk of injury by decreasing muscular and joint stiffness and by preparing the neuromuscular system for coordinated activity. A decent warm-up which includes a variety of whole-body activities should precede the second half of play, just as it does the first half.
The observations that most severe injuries occurred at the knee and that most injuries took place in the leg were also important. To decrease their risk of injury, rugby union players need to do a better job of improving running-specific strength in their legs; to do so, they should use one-leg strengthening movements such as one-leg squats, one-leg hops in place, high-bench step-ups, runners’ poses, and step hopping. Coordination training on unstable surfaces (such as a rocker board or wobble board) should also decrease injury risk, as it has in other sports. Finally, explosive strength training will ensure that good strength is apparent during high-speed movements; drills such as Indian hopping, diagonal runs with cuts, one-leg squats with lateral hops, drop jumps, and high-knee explosions will be useful here. Finally, since rugby union players have frequent problems with hamstring strains and tears, they should practise hamstring-fortifying efforts such as bicycle leg swings.
Why does higher level of play lead to a great risk of injury in rugby union players (remember that the rate of injury was up to five times higher in professional RU players than in recreational athletes, and up to nine times higher than with schoolboys). Theories abound, but it is likely that play is much faster in professional play, and thus contact occurs with greater forces. In addition, elite players are bigger and fitter than their recreational and schoolboy counterparts, and the ball is in play for longer periods of time during professional play, compared with lower-level versions of the game (remember that in-play stages of the game account for a significant fraction of injuries). Interestingly enough, the conversion to professionalism can produce a quite sudden increase in injury rates; one study found that injury rates in Scottish players doubled in just four years after they turned professional (‘Impact of Professionalism on Injuries in Rugby Union’. British Journal of Sports Medicine, Vol. 34, pp. 348-351, 2000).
Turning to this seemingly more refined sport, are the injury rates lower than in rugby? At first glance, cricket would seem to be a relatively safe sport, compared with rugby, yet research shows that it actually accounts for 7% and 4% of adult and child sporting presentations to emergency departments in Australia, making it the fifth and eighth most-common sports presenting, respectively. What can be done to reduce existing cricket-injury rates? To find out, researchers at the University of Melbourne, the Australian Cricket Board, and the Queensland Cricket Association recently analysed injuries and illnesses occurring in Australian cricket at the first-class level over six full seasons (‘Injuries in Australian Cricket at First Class Level 1995/1996 to 2000/2001’. British Journal of Sports Medicine, Vol. 36, pp. 270-274, 2002.) Injuries were defined in a slightly more complicated way, compared with the rugby research. For example, a cricket-player mishap was defined as an injury if any of the following conditions applied:
When these rather broad categories of injury were utilised, the seasonal incidence of injury was found to be about 18 injuries per team per season. Since a squad was typically composed of 25 players, this meant that about 72% of team members were injured in an average Australian summer of play! About 7% to 10% of Australian elite players were missing per match (in other words, when two teams of 25 players played each other, about 3.5 to five players could be expected to be missing in action for at least a portion of the competition); this compares with about a 13% to 16% injury prevalence in rugby union. Pace bowlers had the highest rate of injury, followed by spin bowlers, batsmen, and wicket keepers.
Cricket matches tend to be long affairs, though, and so the rate of injury tended to be low when expressed per hour of play. For example, injury rates were pegged at 1.9 injuries per 1000 player hours in first-class domestic matches (compare this with the rugby Wallabies’ rate of 69 injuries per 1000 hours!) and 3.85 injuries per 1000 player hours in one-day international competitions. Even given the higher international rate, a first-class cricket player is about 6% as likely to be injured during an hour of play, compared with a Wallaby. The major risk factors for injury during cricket play turned out to be bowler speed, a high number of match overs in the previous week, number of days of play, and batting first (bowling second) in a match. One unusual type of injury was highly preventable; seven players were seriously hurt over the six-year period by colliding with a fence when sliding to field a ball, an injury which could be prevented with the use of a simple boundary rope. In addition, 11 players were hurt not during cricket play but during ‘cross training’, which consisted of participation in football; many of these problems were serious knee injuries. Why are bowlers more likely to be injured when their team is bowling second? The answer to this important question is not clear, but an interesting observation is that before the start of the first innings, bowlers will warm up in the nets, whereas in subsequent innings they may start bowling immediately after batting. It is possible that bowlers are not taking proper warm-ups between innings. Bowling injuries are far more common than batting or fielding injuries, and the trunk, lumbar spine, groin, and thigh are the most commonly injured body regions in bowlers. Bowlers are very vulnerable to side strains, which seem most commonly to occur on the non-bowling side of the body; many of these side strains represent damage to and inflammation of the abdominal-muscle insertions on the lower ribs. Hamstring injuries are the most typical problems associated with the thigh.