With an estimated 45 million children and adolescents involved in organized athletics in the United States, it is not surprising that sport is the primary cause of injury in young people (1,2). The majority of injuries are mild strains, sprains, and contusions, with few severe enough to require hospitalization. Despite the relatively low severity of these injuries, they can have a significant impact. Injuries may lead to reduced participation in sport and fitness activities, thus contributing to the childhood obesity epidemic. Injury also may disrupt potential benefits of sport, including increased self-esteem, community involvement, and increased fitness. Injury has direct costs from evaluation, treatment, and rehabilitation, and indirect costs of parental sick leave and lost productivity if parents miss work to tend to an injured child.
Many youth sport-related injuries can be prevented. Prevention strategies include educational programs, rule changes, safety equipment, and preseason and in-season conditioning programs. An excellent review discussing youth sports injury prevention was published in Current Sports Medicine Reports in 2003 (3). Since the publication of that review, a number of new youth injury prevention programs have been evaluated; this article reviews this recent research.
EDUCATIONAL PROGRAMS AND RULE CHANGES
Specific rules have been established to ensure the safety of athletes. Spearing in American football, crosschecking in ice hockey, and tackling from behind in soccer are examples of activities limited by rules designed to protect athletes. Another component of ensuring athlete safety is providing proper sport fundamental instruction. Several educational programs have been adopted by sport-governing bodies to reinforce the importance of adhering to rules, to teach proper fundamentals, and to reduce injury related to poor technique.
Violation of existing rules appears to be a major risk factor for injury. A recent study evaluated nine high school sports to determine the number of sports-related injuries sustained as a result of illegal activity. This study revealed that 6.4% of overall injuries were related to rules transgressions. It was estimated that 98,066 injuries occur nationally on an annual basis as the result of illegal activity. By enforcing existing rules strictly, and by educating athletes about the dangers of rules infractions, a high percentage of injuries potentially could be prevented (4).
Ice hockey is a fast-paced sport with a high rate of injury. A policy statement published in 2000 by the American Academy of Pediatrics (AAP) called for the limitation of body checking, the adoption of fair-play policies, and educational programs emphasizing following the rules and safe play (5). Several recent articles have looked at the effect of implementing these injury prevention practices.
Body checking clearly exposes athletes to injury. Youth leagues with younger participants typically restrict body checking. A recent study examined checking related injuries, confirming that leagues that allowed checking had a higher injury rate than leagues where checking was not allowed. Some hockey experts feel that teaching checking at earlier ages would allow for more time to perfect proper checking technique, and therefore be protective against future injury. However, this study found evidence to the contrary. Players at the bantam level who had learned checking legally at an earlier age had higher odds of sustaining an injury due to checking than the bantam players who were not allowed to check at age 10 and 11. The authors concluded that the early acceptance of body checking raised the injury rate substantially in younger and older athletes (6).
Some hockey governing bodies have adopted "fair play" policies. Teams can earn standings points through victories and ties, but additional standings points may be earned if a team does not accumulate a large number of penalties. Prior studies of fair play programs have shown a reduction in numbers of penalties and injuries (7). The Fair-Play Program (FPP) adopted by Hockey Quebec was recently examined. In games played under the FPP rules, the number of penalties was significantly lower than the number of penalties in the games not played under the FPP. Despite this disparity, there was no difference in the injury rate. There was a statistically insignificant trend toward lower injury severity in the FPP games, but the study was limited by small sample size (8). Further study of the FPP used by Hockey Quebec is warranted to determine whether these rule changes reduce injury rates or severity.
USA Hockey and Hockey Canada have extensive educational programs regarding player safety and injury prevention. USA Hockey implemented its Heads Up Hockey initiative in 1996; this program focuses on reducing head and spinal cord injury through player and coach education. Instructional tools and a DVD are available through USA Hockey. However, there is no recently published literature evaluating the effectiveness of this program (9).
Hockey Canada has provided a similar safety program since 1995 with a focus upon injury prevention and first aid (10). ThinkFirst Canada, a brain and spinal cord injury prevention foundation, has produced a video titled Smart Hockey, which teaches youth players about the causes, symptoms, and prevention of head and spinal cord injury (11). The effectiveness of this program was evaluated in a 2003 study. Players who viewed the video were more familiar than controls with the causes of concussion and spinal cord injury, and they were better able than controls to identify symptoms of concussion. There was a significant reduction in the number of crosschecking and checking from behind penalties in athletes who watched the video. This suggests that preseason educational programs can improve players' knowledge of brain and spinal cord injury, and that such programs can reduce the number of certain high-risk penalties. Further study is warranted to determine whether this program reduces injuries (12).
In summary, studies support the implementation of the recommendations made by the AAP in its 2000 policy statement on ice hockey. Limiting body checking, using fair play policies, and educating athletes have been shown to be effective strategies in youth ice hockey injury prevention.
In an effort to reduce the number of shoulder and elbow injuries in youth baseball pitchers, the USA Baseball Medical and Safety Advisory Committee released a revised position statement in May 2006 addressing pitch counts, pitch types, and appearances made by youth pitchers (13). These recommendations are summarized in the Table. In October 2007, Little League implemented revised rules to limit the number of pitches made by Little League pitchers (14). Both the USA Baseball and Little League position statements outline age-specific pitch count limits. Additionally, USA Baseball advises players to refrain from participating in multiple leagues, participating in year-round baseball, and participating in scouting showcases. Both sets of recommendations are based on a recent paper reporting the results of a case-control study. Pitchers with a history of a significant pitching-related shoulder or elbow injury were more likely than uninjured counterparts to have pitched more months per year, more innings per year, more pitches per game, and more pitches per year. Injured pitchers were more likely to have participated in scouting showcases, andwere more likely to have pitched through arm pain or fatigue (15). It is hoped that implementation of rule changes such as pitch count limitations will prevent a significant number of youth pitching-related injuries.
A variety of safety devices have been designed for athletes in nearly every sport. Many recent studies have evaluated the efficacy of safety devices in preventing injury. Unfortunately, despite the availability of existing safety devices, some athletes choose not to use the equipment. There is an evolving body of literature looking at the effectiveness of promotional campaigns to increase the use of safety devices.
Helmets and Headgear
Helmet use is mandatory in certain sports, but remains optional for many other sports despite significant risk for head injury. Headgear use has increased in soccer, as players are more aware of the potential for traumatic brain injury. A recent study evaluated the effectiveness of three brands of soccer headgear at reducing forces transmitted to the head as the result of heading or direct head-to-head contact. None of the equipment tested showed any attenuation in mechanical forces due to heading, but there was a 33% reduction in acceleration forces from head-to-head impact when the headgear was used (16). Further study is warranted in soccer to evaluate the effectiveness of headgear at preventing injury.
Alpine skiing and snowboarding are popular winter activities that carry a significant risk for head injury. Helmets are mandatory equipment for Féderation Internationale de Ski (FIS) ski events, but helmet use is optional for the recreational skier or boarder. A recent case-control study of recreational skiers and snowboarders revealed a 60% reduction in risk for head injury among skiers using helmets compared with a control group (17). Efforts have been made to increase helmet use among skiers and snowboarders through promotional campaigns. A multi-faceted helmet promotion campaign entitled "It Ain't Brain Surgery" has been evaluated in Colorado. This program used numerous media outlets to promote helmet use. Another component of the program involved a helmet loaner program. Stores offering free loaner helmets with ski rental packages noted a 10-fold increase in helmet acceptance and use. This multi-faceted campaign resulted in an obvious increase in helmet use, although data on injury prevention have yet to follow (18).
In 2004, the AAP Committee on Sports Medicine and Fitness published a policy statement promoting the use of protective eyewear for athletes. Specific manufacturing standards exist for protective eyewear, and protective goggles and glasses meeting these standards were recommended by the committee for specific sports. It was further recommended that functionally one-eyed athletes should wear eye protection for all sports. Functionally one-eyed athletes were recommended to avoid boxing, martial arts, and wrestling due to the significant risk of eye injury in these sports (19).
Squash is a particularly high-risk sport for eye injury because of its rapidly moving, small hard projectile and the close quarters of the competitors wielding long hard rackets. A multi-faceted eyewear promotion strategy similar to the previously mentioned helmet campaign has been evaluated. Promotional and educational materials about eye injury and eye protection were provided at squash venues. Appropriate protective eyewear was available for players to try or purchase. Compared with controls, those players exposed to the promotional program had a 2.4 times increased odds for wearing appropriate eyewear (20). This study, as does the helmet study, shows the potential for increased use of safety equipment when multi-faceted promotional campaigns are undertaken.
Faceguards, Safety Balls, and Chest Protectors
Baseball has a high rate of injury as the result of being struck by the ball. Numerous safety devices are used in youth baseball to reduce the risk of injury. Many youth baseball organizations support the use of faceguards, safety balls, and chest protectors.
In 2001, USA Baseball recommended that youth baseball organizations use reduced-impact safety balls in leagues with young players. This recommendation was made based on the high incidence of injuries related to being struck with the baseball (21). In a recent 3-yr study of Little League Baseball, the injury rate was reduced by 23% when safety balls were used. The use of faceguards reduced the risk of facial injury by 35% (22). Safety balls and faceguards appear to be effective injury prevention strategies when implemented in youth baseball.
Commotio cordis is a rare but devastating event in sport. A recent report revealed that, of 85 recent cases of commotio cordis occurring during organized sport participation, 32 (38%) occurred in athletes wearing chest protectors (23). This report follows another study in which youth baseball and lacrosse chest protectors were evaluated for their ability to prevent commotio cordis. None of the chest protectors were effective at lowering the risk of commotio cordis when compared with wearing no protection at all (24). These studies suggest that wholesale reevaluation of the design and use of chest protectors is necessary to lower the risk of commotio cordis.
A variety of braces are available, with wide variations in price and design. Many athletes elect to use braces for purposes of protection or injury prevention. A recent epidemiologic study revealed that previous lower extremity injury increases the rate of sustaining future lower extremity twofold (25). Those athletes with previous leg injury appear justified in implementing an injury prevention strategy, although bracing may not be the most effective method.
Several recent studies have been published examining ankle braces in volleyball players. An ankle brace ideally would prevent injury without compromising performance or impairing normal ankle function. One case-series examining ankle bracing among volleyball players revealed a significant reduction in ankle injuries among athletes using an ankle brace. The authors reported an injury rate of 0.07 injuries per 1000 athlete exposures, compared with a rate of 0.98 per 1000 exposures reported by the NCAA Injury Surveillance System (26). The Yang study demonstrated that the overall lower extremity injury rate was reduced by use of lower extremity protective equipment, but the modest reduction was attributed entirely to the use of kneepads. When the kneepad data were excluded, it appeared that the use of knee and ankle braces actually increased rates of lower extremity injury (25).
A recent study of athletes with chronic ankle instability found no detrimental impact on agility testing when semi-rigid or soft ankle braces were used. This same study demonstrated a significant subjective difference in terms of comfort, with soft braces being more acceptable than semi-rigid braces (27). The use of external ankle braces in volleyball players over the course of a season does not appear to have a detrimental effect upon dynamic ankle restraint mechanisms (28). In summary, the use of ankle braces may be an effective strategy for preventing ankle injury, although recent data are mixed. There appears to be no measurable adverse impact upon either performance or function based upon recent studies.
Traditional warm-up and cool-down stretching exercises have been a standard routine in competitive and recreational sports. The utility of these exercises has been extensively studied, but findings are inconclusive. A systematic review suggests there is "not sufficient evidence to support or discontinue routine stretching before or after exercise to prevent injury" (29). Although there is little evidence for injury prevention, nearly all coaches surveyed believe that warm-up stretching routines do, in fact, prevent injury (30).
Several recent injury prevention studies have focused on preseason and in-season neuromuscular training, proprioceptive training, and sport-specific skill interventions. Many of these studies have shown beneficial effect with regards to injury prevention.
Neuromuscular training programs have been a mainstay in physical therapy for treatment of injuries. There is evidence that neuromuscular training programs also may be effective in injury prevention, especially with regards to female anterior cruciate ligament (ACL) injuries. A prospective cohort study found that a structured warm-up including strengthening, stretching, plyometrics, and soccer specific skill sets was more effective in reducing ACL injury in adolescent female soccer players than traditional warm-up stretching exercises (31). Another study showed that it is possible to prevent ACL injuries with a neuromuscular program in female handball athletes (32). A meta-analysis of six studies relating to ACL injury prevention in female athletes concluded that neuromuscular training programs may reduce the risk of ACL injury (33). This study recommends training programs that also emphasize performance enhancement as a means to motivate compliance in athletes.
It is unknown whether any one training program is superior to other training regimens for preventing ACL injuries. One study compared a basic resistance training program with a plyometric training program in high school female athletes. Both regimens induced favorable mechanics, but outcome data regarding injuries were not reported (34).
Myrick performed a small study of one basketball team using performance enhancement and an injury prevention training program with positive results (35). However, this study was limited by small sample size and lack of a control group. The results suggest that programs incorporating performance enhancement to motivate athlete compliance may produce lower injury rates, but further study is warranted.
Proprioceptive balance training, like neuromuscular training, is used frequently for treatment of sports-related injuries and has been studied as an element in injury prevention. Emery et al. studied the effectiveness of a home-based wobble board program. Initial studies were promising in reducing sports-related injuries among healthy adolescents (36). In a follow-up wobble board study, no statistically significant results were observed, but self-reported compliance was low. However, a potentially clinically relevant trend in favor of reducing lower extremity injuries was observed (37). McGuine et al. studied the effect of a balance training program on the risk of ankle sprains in adolescents. The rate of ankle sprains was 6.1% in those athletes who underwent the training program compared with 9.9% in the control group (38). Those with a previous history of ankle sprains in the intervention group decreased their risk of having an ankle sprain by one-half. In summary, the evidence suggests balance training programs are effective in preventing ankle sprains, especially in those athletes with a history of previous ankle sprains.
Sports with frequent jumping, landing, and high-speed running with rapid directional change have a higher rate of injury. The influence of preseason and in-season skill-specific injury prevention programs has been studied. Scase et al. studied the effectiveness of a preseason physical training program geared at improving landing skills in elite, under 18, male Australian football players. It was found that the intervention resulted in an overall improvement in landing skills, with a subsequent reduction in injury risk(39).
Researchers also have studied the influence of in-season injury prevention training upon hip and knee kinematics specific to landing in female soccer players. The training program induced significant changes in biomechanics that may play a role in ACL injury (40). Replacement of traditional warm-up and cool-down routines with structured warm-up programs can prevent injury, especially to the knee and ankle. Efforts should be made to incorporate such injury prevention training programs into youth sports (41).
Based upon the recent available data, there are numerous strategies that can be implemented in youth sports to effectively prevent injuries. Enhancing the safety of athletes may lead to greater enjoyment of and longer participation in sports. Given the recent pediatric obesity epidemic, it stands to reason that medical professionals should promote safe and enjoyable physical activities for our youth. Strong evidence exists that supports the implementation of altered rules, use of safety equipment, and participation in specific conditioning programs. Enforcement of rules designed to protect athletes should be uniform. Education of parents and coaches must continue regarding evolving injury prevention methods. Sports medicine providers who care for young athletes are in a unique position to stay abreast of new literature on injury prevention and to educate athletes, parents, and coaches of new ways to protect our young athletes.
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