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significant when limited to non-contact ACL injuries incurred during the season (0.06 vs 0.00; P < 0.05). There was a significant difference in the rate of ACL injuries in the second half of the season, from week 6 to week 11, with 0 injuries in the intervention group and 0.18 injuries per 1000 athletic exposures in the controls (P < 0.05). This supports the notion that 6–8 weeks of training are needed before a neuromuscular effect is observed (8).
HEAD INJURIES Head injuries have been – and continue to be – a major concern in the sporting world. Football players use their heads throughout the game, without any protective headgear, to change the direction of the ball at high speed in order to score goals. This is a critical skill, but it places the player at risk of various head injuries, including contusions, lacerations, facial fractures and concussion (42). There are many concerns about the long-term adverse
effects of concussion or even sub-concussive impacts during the course of play. Evidence suggests that “purposeful” headings are not deleterious and that concussive episodes are associated with accidental contacts with another player (head to head or head to elbow) or the ground, but most football players are concerned with the long-term sequelae (43,44). In the USA, there are around 300,000 sports- related concussions a year, and the likelihood of a contact- sport athlete being concussed in any season may be as high as 19% (44). Athletes who experience a concussion usually recover
fully, but an unknown number may experience chronic cognitive and neurobehavioral difficulties if they are injured repeatedly. The range of symptoms is summarised in Table 4 and may include chronic headaches, fatigue, sleep difficulties, personality changes (e.g. increased irritability or emotionality), sensitivity to light and noise, dizziness when standing quickly, and deficits in short-term memory, problem- solving and general academic functioning. This constellation of symptoms is referred to as “post-concussion syndrome” and it can be quite disabling for an athlete and, in some cases, permanent. On top of this, a second blow to the head while recovering from an initial head injury can have catastrophic consequences, and this is known as “second impact syndrome” which has led to approximately 30–40 deaths over the past decade (45). The controversy about protective headgear in football
began after some early epidemiological studies, such as those by Tysvaer (46) on professional players in Norway, identified cognitive deficits among retired players, and attributed them to repetitive trauma caused by heading the ball. The validity of these conclusions are questionable because numerous confounding factors were not controlled for (47), such as the weather, in as much as a leather football will absorbs rain or surface water and become heavier. In studies of modern, water-resistant, synthetic footballs were conducted, the players show no cognitive deficits (48). Fuller et al. (49) conducted a study on the most likely
risk factors for head and neck injuries in football players, focusing on male and female players who sustained a head and/or neck injury during 20 FIFA international tournaments. A total of 248 head and neck injuries were recorded, of which 163 were analysed on video footage, and
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they comprised 53% contusions, 20% lacerations and 11% concussions. There were 12.5 injuries per 1000 player hours (men 12.8; women 11.5) and 3.7 time-loss injuries (men 3.5, women 4.1). Most were caused by challenges in the air (55%) and the impact of an arm (33%) or head (30%). The impact of an arm on another player was significantly more likely to cause an injury than any other action. Interestingly, it was noted that only one injury occurred as a result of heading the ball (0.05 injuries per 1000 player hours). Purposeful heading and adoption of fair play by all players is the most effective means of reducing head injury in the footballer.
TABLE 4: POTENTIAL COGNITIVE AND NEUROBEHAVIORAL SEQUELAE OF CONCUSSION
n Chronic headaches n Sleeping difficulties n Sensitivity to light
n Dizziness on standing quickly n Problem-solving deficits
n Fatigue
n Increased irritability or emotionality n Sensitivity to noise
n Short-term memory deficits
GLOBAL INJURY PREVENTION IN FOOTBALL Steffen and colleagues (14) from the Oslo Sports Trauma Research Center attempted to reduce the incidence of football-related injuries. They tested a set of exercises known as the “11” in a cluster-randomised controlled trial in 1091 female football players in 59 teams. There were 1001 controls in 54 teams. The 8-month exercise routine comprised a 15-minute warm-up for core stability, lower extremity strength and neuromuscular control and agility. A total of 396 players (20%) sustained 483 injuries in both groups. There was no difference in overall injury rate between the intervention (3.6 injuries per 1000 hours; CI 3.2–4.1) and control groups (3.7; CI 3.2–4.1; RR = 1.0: CI 0.8–1.2; P = 0.94) nor in the incidence for any type of injury. The training programme was used during 60% of training sessions in the first half of the season, but there was low compliance – only 14 out of 58 intervention teams completed more than 20 sessions. There was no effect of the prevention programme on the injury rate, possibly because the programme was not specifically aimed at these athletes’ particular biomechanical deficiencies and the low compliance (14). In order to address some of these shortcomings, this programme was restructured in a second study. Soligard et al. (50) completed a cluster randomised controlled trial of the “11+” in 125 football clubs from southern, eastern and middle regions of Norway. There were 65 clusters in the intervention group and 60 in the control group for one league season (8 months). There were a total of 1892 female players aged 13–17, with 1055 and 837 in the intervention and control groups, respectively. The 11+ warm-up programme aimed to improve strength, awareness and neuromuscular control during static and dynamic movements. During the season, 264 players had relevant injuries, 121 in the intervention group and 143 controls (RR 0.71; 95% CI 0.49–1.03). In the intervention group there was a significantly lower risk of overall injuries (0.68; 95% CI 0.48–0.98), of overuse injuries (0.47; 95% CI 0.26–0.85) and of severe injuries (0.55; 95% CI 0.36–0.83). The primary outcome – reduction in lower-limb injury – did not reach statistical significance, but the risk of
sportEX medicine 2011;47(Jan):14-21