Psychology of Sport Injury Course 1_Part4.pdf

Antecedents of Sport Injury   35 nisms by which psychosocial factors influence sport injury occurrence. On the other hand, the stress–injury model is a psychosocially oriented framework, and it speaks more explicitly about the role of psychosocial factors in sport injury occurrence. As argued earli...

Antecedents of Sport Injury   35 nisms by which psychosocial factors influence sport injury occurrence. On the other hand, the stress–injury model is a psychosocially oriented framework, and it speaks more explicitly about the role of psychosocial factors in sport injury occurrence. As argued earlier in this chapter, using the terminology of the multifactorial model, psychosocial factors contribute to athletes becoming both predisposed to injury (i.e., possessing a typically distal element of risk that makes injury more likely) and susceptible to injury (i.e., being on the verge of becoming injured, pending the presence of an inciting event). Psychosocial factors can even feature prominently in the inciting events that represent the last step in the causal chain—for example, when an angry opponent delivers a “cheap shot” to an athlete or when an athlete makes a fateful decision to push on despite experiencing a muscle twinge during competition. In their original article on the stress–injury model, M.B. Andersen and Williams (1988) proposed three primary proximal mechanisms by which psychosocial factors contribute to sport injury occurrence: muscle tension, distracted attention, and narrowed peripheral vision. Each of these mechanisms is thought to result directly from the stress response, which itself is thought to be influenced by personality, history of stressors, and coping resources. Empirical support for the proposed mechanisms varies. Despite the widespread notion that muscle tension emerges from the stress response, disturbs coordination, reduces flexibility, and contributes to the occurrence of a variety of musculoskeletal injuries (e.g., strains, sprains), these assertions are supported by remarkably little evidence. In contrast, there is some support for the idea that athletes become distracted under stressful conditions, whereupon they fail to attend to vital cues in the sport environment and sometimes become injured when a missed cue leads to an inciting event (e.g., collision, misstep). For example, as noted earlier, American football players who had experienced a major stressor in the past year experienced elevated risk for injury if they were low in attentional vigilance (N.J. Thompson & Morris, 1994). Similarly, although the finding was not linked directly to the stress response, Swanik et al. (2007) found that collegiate athletes who sustained a noncontact injury to the anterior cruciate ligament (ACL) scored more poorly on a preseason test of visual attention than did a matched group of their peers who did not incur such an injury. The strongest empirical support for a proposed mechanism by which a psychosocial factor affects sport injury occurrence involves narrowed peripheral vision. M.B. Andersen and Williams (1988) argued that “during stress, narrowing of the visual field may occur, leading to a failure to pick up vital cues in the periphery and thus increasing the likelihood of injury (e.g., getting blind-sided)” (p. 299). In fact, athletes have been shown to experience narrowing of peripheral vision during stressful conditions involving both laboratory stressors (J.M. Williams & Andersen, 1997; J.M. Williams, Tonymon, & Andersen, 1990, 1991) and real-life stressors (T.J. Rogers et al., 2003). For example, M.B. Andersen and Williams (1999) reported that among a sample of collegiate athletes with low social support, those who were high in negative life stress and peripheral narrowing sustained more injuries than did those who were low in negative life stress and peripheral narrowing. More recently, T.J. Rogers and Landers (2005) demonstrated that peripheral narrowing mediated 8 percent of the relationship between negative life stress and sport injury in a sample of high school athletes. Elaborating on the physiological and psychological aspects of the stress response, Petrie and Perna (2004) extended the hypothesized influence of the stress response to include the following prospective and interrelated mechanisms: • • • • Suppressed immune system Disrupted tissue-repair process Compromised sleep Altered self-care behavior Empirical links have been documented between stress and each of these four proposed mechanisms. For instance, immunosuppressive B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. 36 Psychology of Sport Injury effects are well documented for long-lasting chronic stress (Segerstrom & Miller, 2004). Moreover, coupling life stress with rigorous physical training, both of which involve the secretion of the stress hormone cortisol, further suppresses the immune system (Perna & McDowell, 1995) and can inhibit processes vital to healing muscle and other body tissues (Kiecolt-Glaser, Page, Marucha, MacCallum, & Glaser, 1998; Petrie & Perna, 2004). Stress can also interfere with sleep duration and quality (Cartwright & Wood, 1991; Van Reeth et al., 2000; W.F. Waters, Adams, Binks, & Varnado, 1993), which can bring about conditions conducive to the occurrence of injury—for example, compromised immune functioning, diminished concentration, slowed reaction time, hampered perception, increased aggressiveness, impaired decision making, and reduced secretion of growth hormone (Orzel-Gryglewska, 2010), which is a contributor to healing. In addition, stress can interfere with one’s ability or inclination to take care of oneself (Heatherton & Penn, 1995; Steptoe, Wardle, Pollard, & Canaan, 1996), which, for athletes, may contribute to neglecting to eat nutritious meals, hydrate sufficiently, or engage in adequate stretching, strengthening, or other preventive activities (Petrie & Perna, 2004). Taking stock, although logical and theoretical connections can be drawn between these four mechanisms and the occurrence of sport injury, the hypothesized relationships have not been tested empirically and are therefore currently without research support. Another potential mechanism by which psychosocial factors might influence the occurrence of sport injury lies in the behavior of athletes and their opponents in the competitive sport setting. Although this mechanism has been largely neglected in scientific literature on the psychosocial antecedents of sport injury, Bahr and Krosshaug (2005) identified player and opponent behavior as one of four categories of inciting events that could bring about injury in susceptible athletes. This cat- egory could also include the cognitive and emotional underpinnings of athletes’ actions toward and interactions with their opponents, because in some cases an athlete’s decision to behave in a particular way (e.g., to initiate hard contact) is what sets in motion a course of events that culminates in an injury. At the same time, a player’s behavior need not involve interaction with an opponent; it could simply reflect a decision made in the heat of competition (e.g., attempting a sharp turn without braking). Opponent behavior could be either intentionally or unintentionally (i.e., accidentally) injurious. Although little is known about athlete (and opponent) behavior as a mechanism of sport injury, insight may be provided by several lines of research. For example, Bredemeier and her colleagues (e.g., Bredemeier, 1985; Bredemeier, Weiss, Shields, & Cooper, 1987) have extensively examined intentionally injurious acts in sport from the perspective of moral reasoning. This research may prove helpful in identifying athletes who are likely to attempt to injure opponents intentionally, why they might choose to do so, and which opponents they might attempt to injure. With regard to the latter issue, Soligard, Grindem, et al. (2010) found that high levels of technical skill, tactical skill, and physical strength were associated with an elevated risk of injury in soccer players. This finding suggests the possibility that strong players in some sports may be targets of opponent behavior that confers an increased risk of injury. In another area of inquiry, fine-grained, video-based analyses have enabled researchers to determine the events immediately preceding injury in professional soccer players (T.E. Andersen, Larsen, Tenga, Engebretsen, & Bahr, 2003). In one study, the vast majority of ankle sprains observed were attributable to illegal tackles from the side in which the medial portion of the injured player’s lower leg was struck by an opponent’s foot (T.E. Andersen, Floerenes, Arnason, & Bahr, 2004). Thus, the influence of opponent behavior as B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. Antecedents of Sport Injury   37 an inciting event can be observable, quantifiable, and subject to analysis. Biopsychosocial Analysis Let us now return to the case of Alex, which led off the chapter. In hindsight, it is not surprising that he incurred an injury during the lacrosse season. Indeed, he (unintentionally, of course) collected risk factors for sport injury like they were going out of style. In addition to his previous injury to the same body part (shoulder) the year before, he experienced a series of major life events (the death of his father; the breakup of his romantic relationship; his mother’s alcohol abuse; and increased responsibilities for household tasks, an internship, and a heavy course load) that compromised his health behavior (e.g., insomnia, poor eating habits) and left him weakened, distracted, and unfocused on the sport tasks at hand. The circumstances of Alex’s injury are highly consistent with prominent models of sport injury etiology. In terms of the multifactorial model, Alex’s previous shoulder injury made him predisposed to subsequent injury; in turn, the stressful life events and their consequences increased his vulnerability until, finally, he sustained an injury upon encountering an unspecified inciting event, which may have been made more likely by his lack of focus. In terms of the stress–injury model, Alex had several risk factors that could have led to his injury. Little is revealed about his personality, but he had a history of stressors (i.e., major life events, previous injury) and an erosion of coping resources (at least in terms of social support, as evidenced by the dissolution of his romantic relationship and the death of his father) that appear to have affected his cognitive, behavioral, and, perhaps, physiological responses in ways that may have amplified his susceptibility to injury. One of the primary benefits of models of sport injury etiology is that they suggest points of entry for preventive interven- tion. Although Alex’s previous injury could not have been undone, his predisposition to future injury could conceivably have been modified by ensuring complete rehabilitation of his prior injury (if it was not). Similarly, although the stressful events he experienced might also have been unavoidable, he might have benefited from stress management training, academic support services, and social support. These measures might have helped Alex develop coping skills and given him resources to alter his reactions to life stressors, minimize his stress response, and, potentially, reduce his odds of incurring the new injury. Preventive efforts of this sort are addressed at length in chapter 3. Summary When we seek to develop strategies and interventions for preventing (or at least minimizing) and managing injuries, it is helpful to examine models of why and how athletes are injured and to know the psychosocial predictors of sport injury. To that end, this chapter presents two schools of thought regarding sport injury occurrence: 1. The multifactorial model of sport injury etiology 2. The stress–injury model The multifactorial model proposes that factors in sport injury include both intrinsic or personal items (e.g., previous injury, joint stability, age, physical conditioning level) and extrinsic or environmental factors (e.g., nature of chosen sport, exposure to injury-enabling situations, coaching, equipment, environmental influences). Modifications of the model have added the concept of the inciting event, which includes the playing situation, the behavior of the athlete and opponents, and biomechanical characteristics. The stress–injury model, on the other hand, posits the stress response as the proximal cause of sport injury. The stress response B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. 38 Psychology of Sport Injury is described as resulting from the cognitive appraisals that athletes make in stressful competitive sport situations. Cognitive appraisals are influenced by three broad categories of psychosocial factors: personality (i.e., welllearned patterns of thinking, feeling, and behaving), history of stressors (e.g., minor and major life events, previous injury, daily hassles), and coping resources (e.g., stress management techniques, proper rest and nutrition, social support). Cognitive appraisals affect both physiological and attentional processes that can influence the occurrence of sport injury. Although these two models evolved independently and appear to be quite different, they are in fact complementary; more specifically, the stress–injury model represents a specific pathway within the multifactorial model. Both models have been the source of considerable research and have made important contributions to understanding the etiology of sport injury. Consistent with the tenets of these models, numerous psychosocial factors have been identified as predictors of sport injury occurrence and time lost due to injury. Some factors have been linked to sport injury in a single study, whereas others have repeatedly emerged as predictors across multiple studies. Although no “injury-prone” personality has been identified, personality is one psychosocial category connected to injury occurrence. Personality factors associated with injury include hardiness, locus of control, competitive trait anxiety, and achievement motivation. For example, higher levels of competitive trait anxiety are related to more and longer-lasting injuries. In addition, several studies have found a positive association between the type A personality pattern and overuse injuries in runners. The most studied and consistently supported psychosocial predictor of sport injury is history of stressors. Total life-event stress (i.e., total stress from negative and positive life events) has frequently been correlated positively with subsequent injury. In contrast, little research has been conducted on the relationship between minor life events (e.g., daily hassles) and sport injury occurrence. Coping resources have received the least attention from researchers and have demonstrated the fewest associations with sport injury occurrence. Studies examining the relationship between coping resources (e.g., coping strategies, social support) and sport injury occurrence and severity have been inconclusive. Additional psychosocial variables that have been identified as predictors of sport injury include neurocognitive functioning, perceived motivational climate, physical self-perceptions, positive states of mind, and sociability. High levels of perceived mastery climate, perceived sport competence, and sociability are associated with elevated risk of injury, whereas low levels of neurocognitive functioning and positive states of mind are inversely related to injury risk. Relatively little is known about the mechanisms by which psychosocial factors affect sport injury occurrence. A variety of mechanisms have been proposed, including muscle tension, distracted attention, narrowed peripheral vision, suppressed immune functioning, disrupted tissue-repair process, compromised sleep, altered self-care behavior, and athlete and opponent behavior. Collectively, these factors may serve as a bridge between psychosocial factors and the occurrence of sport injury. B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. 42 Psychology of Sport Injury These cases, reported by Davis (1991), were not the randomized, controlled clinical trials necessary to demonstrate causation. They do, however, suggest that a sport psychology intervention consisting of relaxation and imagery might have a beneficial effect on injury rate in competitive athletes. In both cases, the goal of the intervention was not to prevent injury but to enhance performance. Even so, reduction in the occurrence of injury appears to have been an unintended favorable by-product. Sport injury is a public health problem that exacts enormous personal and social costs, and prevention has been advocated as one means of addressing the issue (Emery, 2010; Klügl et al., 2010). As a result, recent years have brought increased emphasis on prevention of sport injury in both research and clinical practice (Klügl et al.; Matheson, Mohtadi, Safran, & Meeuwisse, 2010). The upswing in preventive efforts has also been reflected in the staging of a quartet of world congresses on sport injury prevention, which were held in 2005, 2008, 2011, and 2014. To prevent sport injury, we must first understand how it occurs. Fortunately, as shown in chapter 2, an understanding of the antecedents of sport injury is emerging, and that understanding informs efforts to prevent the occurrence of sport injury. Because sport participation carries inherent risks, it is unlikely that we will ever completely prevent sport injury. However, learning about the factors that are related to—or, better yet, contribute to—sport injury occurrence can help us identify points of entry for preventive intervention. With that fact in mind, this chapter examines sport injury prevention with a particular emphasis on psychosocial aspects. It reviews types, models, and categories of prevention and addresses practical considerations for implementing preventive interventions. focus, therefore, on sport injury prevention, which can be categorized into three types: primary, secondary, and tertiary. Primary prevention involves actions taken prior to the occurrence of sport injury, and these preventive efforts are extended to the entire population of interest (e.g., all athletes in a given league or in a certain club), regardless of individual members’ level of risk. For example, if a requirement for hockey players to wear a mouth guard were implemented as a form of primary prevention, even players with no teeth would have to wear a mouth guard. Most preventive interventions that target sport injury fall into the category of primary prevention. Secondary prevention involves actions taken prior to injury occurrence among individuals deemed to be at elevated risk for sport injury within a larger population of interest. Individuals possessing one or more of the risk factors for sport injury identified in chapter 2 are targeted for intervention, thus enabling the concentration of preventive resources on those who need them the most. For example, Maddison and Prapavessis (2005) implemented a stress management intervention with rugby players who were low in social support and high in avoidance coping—factors that the researchers had previously demonstrated as placing the players at increased risk for injury. Tertiary prevention is not prevention at all in the traditional sense of the word. Rather, in tertiary prevention, athletes are treated as soon as possible after injury occurrence in an attempt to minimize the damage to the injured body part. Efforts are also made to rehabilitate injured athletes to the maximum extent possible. Most of the treatment that athletes receive for their injuries from sport health care professionals can be classified as tertiary prevention. Types of Prevention Models of Sport Injury Prevention The surest way to prevent sport injury is for people not to participate in sport. Of course, this solution is neither viable nor desirable— people will choose to participate in sport and expose themselves to the resulting risks. We Several frameworks have emerged to guide sport injury prevention efforts. These frameworks serve as models to ensure that sport injury research and practice proceed in an organized, scientific manner. Models of sport B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. Sport Injury Prevention   43 injury prevention have been proposed by W. van Mechelen, Hlobil, & Kemper (1992), Finch (2006), and Van Tiggelen, Wickes, Stevens, Roosen, and Witvrouw (2008). The model put forward by W. van Mechelen et al. proposed a four-step framework. The first step involves identifying the magnitude of the sport injury problem and describing the incidence and severity of sport injury. The second step involves determining the etiology and mechanisms of sport injury, and the third step involves introducing preventive measures. The final step involves assessing the effectiveness of the preventive measures introduced in the third step by essentially repeating the first step—that is, checking whether the incidence and severity of sport injury have changed as a result of the preventive efforts. Finch (2006) acknowledged that the model proposed by W. van Mechelen et al. (1992) had been valuable in guiding research on sport injury prevention and aligning it with public health approaches to injury prevention outside of sport, but she also identified a major shortcoming of the model. Specifically, it failed to consider challenges in implementing injuryprevention measures in sport settings; in fact, it completely neglected factors contributing to the adoption (or nonadoption) of preventive behavior. To remediate this deficiency, Finch proposed the six-step TRIPP framework, which is short for Translating Research into Injury Prevention Practice. The first four steps of TRIPP resemble the four steps of the model put forth by W. van Mechelen et al. (1992). Specifically, step 1 of TRIPP consists of injury surveillance—an ongoing process of monitoring the occurrence of sport injuries in order to establish the extent of the problem and gauge progress toward achieving prevention aims. Step 2 is identical to the second step of the van Mechelen model—establishing the etiology and mechanisms of injury. Step 3 involves using a multidisciplinary approach based on theory and research to identify possible solutions to the sport injury problem and develop corresponding preventive interventions. Step 4 consists of subjecting the preventive measures generated in the third step to evaluation under “ideal conditions”—that is, laboratory or controlled clinical or field settings in which researchers deliver interventions to coaches and athletes who have been convinced and helped to participate through incentives and reminders. In the fifth and sixth steps of TRIPP, Finch (2006) departs from the model of W. van Mechelen et al. (1992). The purpose of TRIPP step 5 is to “describe intervention context [in order] to inform implementation strategies” (p. 4). This process involves getting a sense of the real-world sport contexts in which to apply the preventive measures developed in step 3 and evaluated in step 4. Doing so requires gathering information about athletes’, coaches’, and administrators’ knowledge, attitudes, and current behaviors regarding sport safety practices. Ultimately, the critical tasks of step 5 are to determine how likely the target sport populations are to accept and adopt preventive interventions and to plan for the implementation of the interventions. In step 6, based on the information gathered in step 5, the preventive measures are implemented and evaluated in naturalistic sport settings under real-world conditions. In addition, whereas step 4 examined the efficacy of interventions, step 6 assesses their effectiveness (for more on the distinction between these two terms, see this chapter’s Focus on Research box). Despite their importance, steps 5 and 6 are underrepresented in the research literature (Klügl et al., 2010). Van Tiggelen et al. (2008) agreed with the contention of Finch (2006) that, contrary to the model of W. van Mechelen et al. (1992), merely showing that a preventive measure reduces the incidence or severity of injury is insufficient to demonstrate the effectiveness of that measure. As depicted in figure 3.1, they argued that for a preventive measure to be found effective, additional criteria must be satisfied. Specifically, after finding the preventive measure efficacious in the fourth steps of the W. van Mechelen et al. and Finch models, it is also necessary to show that the measure displays efficiency, is complied with adequately, and does not adversely affect risk taking. The first criterion, efficiency, is demonstrated when those involved in adopting and B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. 44 Psychology of Sport Injury Establishing the extent of the injury problem Step 1 Establishing the aetiology and mechanisms of the injury Step 2 Proposing a preventive measure Step 3 Establishing the efficacy of a preventive measure Step 4 Poor Good Poor Establishing the efficiency of a preventive measure Assessing the compliance and risktaking behavior for a preventive measure Good Poor Steps 5 and 6 Good Assess assumed effectiveness of prevention by repeating step 1 Step 7 Figure 3.1 Sequence of injury prevention. Reproduced from British Journal of Sports Medicine, "Effective prevention of sports injuries: A model integrating efficacy, efficiency, comE5665/Brewer/F03.01/541466/MattH-R2 pliance and risk-taking behavior," D. Van Tiggelen et al., 42: 648-652, 2008, with permission from BMJ Publishing Group Ltd. implementing preventive measures (e.g., administrators, coaches, athletes) deem that the benefits (e.g., fewer injuries, lower medical costs, fewer lost training hours, less postinjury distress) outweigh the costs (e.g., monetary expenses of prevention-related goods and services, time required to implement measures, discomfort or restricted movement when wearing protective gear). The second criterion, compliance, is satisfied when the preventive measures are introduced and are adhered to by intervention recipients. As discussed in chap- ter 6, the extent to which people adhere to interventions related to sport injury is influenced by a multitude of personal, social, cognitive, emotional, and behavioral factors. Compliance with preventive measures cannot be assumed, even for highly motivated athletes. The third criterion, which involves risktaking behavior, is satisfied by the avoidance of “risk homeostasis” (Wilde, 1998), in which the beneficial effects of prevention are offset by a corresponding increase in risk taking. It can be challenging to avoid risk homeostasis (also B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. Efficacy Versus Effectiveness Effectiveness studies are needed because interventions that succeed in the controlled environment of efficacy studies sometimes fail miserably when put into practice in the real world. For a vivid example outside of the domain of sport injury prevention, one need look no further than interventions pertaining to physical activity. Evidence abounds of the beneficial effects of exercise on a wide variety of physical and mental health outcomes. If people exercise with the appropriate frequency, duration, and intensity for a long enough period of time, they are likely to reap benefits. But that’s a big if, because dropout rates for exercise programs stand at about 50 percent (Buckworth & Dishman, 2007). Presumably, the same question applies to programs aimed at sport injury prevention. As emphasized by Van Tiggelen et al. (2008), preventive measures shown to be efficacious will be effective only to the extent that athletes complete the efficacious measures. An athlete may fail to complete a sport injury prevention program for any of many reasons. For example, coaches may not provide adequate time or support, the intervention may not be delivered with fidelity to the original, or the athlete might simply fail to adhere to the requirements of the program. Steps 5 and 6 in the TRIPP framework (Finch, 2006) are devoted to understanding and overcoming the barriers to successful implementation of efficacious interventions to prevent sport injury. In the end, interventions that are not efficacious are highly unlikely to be effective, and interventions that are efficacious still may be either effective or ineffective. Additional research efforts beyond efficacy studies are needed to help translate promising preventive methods into real-world practice. known as “risk compensation”), as illustrated by the following research findings: Skiers and snowboarders who wore a helmet went nearly 5 kilometers per hour faster than those who did not wear a helmet (Shealy, Ettlinger, & Johnson, 2005); children who wore safety gear proceeded through an obstacle course featuring various hazards faster and more recklessly than those who did not wear safety gear (Mor- rongiello, Walpole, & Lasenby, 2007); and athletes in collision sports (e.g., hockey, rugby) reported that they play more aggressively when wearing protective gear (C.F. Finch, McIntosh, & McCrory, 2001; Woods et al., 2007). The dangerous behavior that characterizes risk homeostasis may be underlain by erroneous beliefs about the protective capabilities of safety gear (Chaduneli & Ibanez, 2014). Focus on Research The TRIPP framework (C.F. Finch, 2006) highlights the distinction between efficacy studies and effectiveness studies pertaining to the prevention and treatment of sport injury. Whereas efficacy research examines an intervention’s success in preventing or reducing sport injury occurrence under controlled experimental conditions, effectiveness research evaluates success in a naturalistic, real-world environment. In essence, efficacy research addresses whether the intervention can work, whereas effectiveness research addresses whether it does work in the real world. Both types of study are vital to the eventual success of interventions designed to prevent or reduce sport injury occurrence. Once researchers have identified factors that cause or contribute to the incidence of sport injury, they can develop interventions that alter those causal or contributing factors in an attempt to decrease the injury rate. Newly developed interventions are then subjected to scientific scrutiny in efficacy studies, first simply to demonstrate that the intervention is feasible (i.e., “proof of concept”) and later to show that the intervention has the intended effect on the occurrence of sport injury. The gold standard for intervention research is the randomized controlled trial (RCT), in which eligible participants are randomly assigned to a treatment or no-treatment group. RCTs are often used in efficacy research because they allow for a critical test of the intervention’s potency. In providing the critical test of the intervention, however, an artificial study environment can be created in which extraneous, real-world influences are minimized. Interventions are typically delivered, by the investigators themselves, to participants (e.g., athletes) whose involvement in the study is encouraged, supported, and reinforced by the researchers and by coaches and administrators (Finch, 2006). B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. 45 46 Psychology of Sport Injury Content Categories of Sport Injury Prevention Given the many factors associated with the occurrence of sport injury, efforts to prevent sport injury vary widely in focus. Still, Klügl et al. (2010) have identified three main categories of content in sport injury prevention: 1. Training 2. Equipment 3. Regulation These categories are described in the following sections, along with an additional category that is a mere blip on the radar screen of sport injury prevention: psychosocial intervention. Training Training intervention, which is currently the dominant form of sport injury prevention in research investigations (McBain et al., 2011), consists of “all forms of physical preparation for sport and exercise” (Klügl et al., 2010, p. 408). Common targets of training include agility; balance; sport-specific skills; and muscular strength, endurance, and power. One popular preventive approach in this category is “neuromuscular training,” which “incorporates general (e.g., fundamental movements) and specific (e.g., exercises targeted to motor control deficits) strength and conditioning activities, such as resistance, dynamic stability, core-focused strength, plyometric, and agility, that are designed to enhance health and skillrelated components of physical fitness” (Myer et al., 2011, p. 157). The rationale for neuromuscular training holds that • biomechanical and other physical deficits underlie many sport injuries; • neuromuscular training helps reduce the deficits that underlie the injuries; and, therefore, • completing neuromuscular training reduces the occurrence of sport injuries. These assertions have been supported by empirical evidence. For example, screening of neuromuscular characteristics (e.g., certain patterns of electrical activity in the knee flexor and extensor muscles) has been found to predict the occurrence of ACL rupture (Zebis, Andersen, Bencke, Kjær, & Aagaard, 2009). In addition, neuromuscular training can lower the levels of sport injury risk related to biomechanics, flexibility, and strength (e.g., Lim et al., 2009). Research also suggests that neuromuscular training is an efficacious strategy for decreasing injury risk among both youth and adult sport participants (Aaltonen, Karjalainen, Heinonen, Parkkari, & Kujala, 2007; Abernethy & Bleakley, 2007; Campbell et al., 2014; Gagnier, Morgenstern, & Chess, 2013; Lauersen, Bertelsen, & Andersen, 2014; O’Malley, Murphy, Gissane, McCarthy-Persson, & Blake, 2014; Parkkari, Kujala, & Kannus, 2001; Pasanen et al., 2008). One primary advantage of neuromuscular training is its adaptability; specifically, it can be readily tailored to the age and chosen sport in the population of interest. For example, efficacious neuromuscular training programs have been developed specifically for youth sport participants (Myer et al., 2011); basketball players (e.g., Emery, Rose, McAllister, & Meeuwisse, 2007); soccer players (e.g., Emery & Meeuwisse, 2010; Mandelbaum et al., 2005); and prevention of injury in certain parts of the body, such as the ankle (e.g., Bahr & Lian, 1997; Stasinopoulos, 2004; E. Verhagen et al., 2004) and the ACL (e.g., Caraffa, Cerulli, Projetti, Aisa, & Rizzo, 1996; Mandelbaum et al.; Myklebust et al., 2003). As with any intervention, the success of neuromuscular training programs presumably depends at least in part on adherence to program requirements (Hägglund, Atroshi, Wagner, & Waldén, 2013; Soligard, Nilstad, et al., 2010; Sugimoto et al., 2012). One prime example of a widely disseminated neuromuscular training program can be found in the “11+” prevention program (as well as its predecessor, “The 11”). Developed with the support of the Fédération Internationale de Football Association (FIFA), the worldwide governing body for soccer, the 11+ program consists of a series of soccerspecific running, strengthening, jumping, and balancing exercises that can be completed as B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics. Sport Injury Prevention   47 a warm-up in about 20 minutes by players who are familiar with it (Soligard et al., 2008). Freely available on the web, the 11 and 11+ programs have been subjected to extensive evaluation in Switzerland (Junge et al., 2011; Junge, Rosch, Peterson, Graf-Baumann, & Dvorak, 2002), Norway (Soligard et al., 2008; Soligard, Nilstad, et al., 2010), the Netherlands (A. van Beijsterveldt, Krist, van de Port, & Backx, 2011b), Canada (Steffen, Emery, et al., 2013; Steffen, Meeuwisse, et al., 2013), and the United States (Silvers, Mandelbaum, Bizzini, & Dvorak, 2014). Research findings have generally supported the programs’ efficacy and effectiveness. In Switzerland, where soccer injuries account for annual health care costs of approximately $130 million, the 11 program was used as part of an ambitious countrywide campaign to reduce the incidence of soccer injuries by 10 percent. All coaches of amateur teams in the national soccer association were given instruction in how to implement the program in their training. Four years later, more than half of the coaches reported that their teams were still performing all or most of the program. Players on these teams experienced 12 percent fewer match injuries, 27 percent fewer noncontact match injuries, and about 25 percent fewer training injuries than did players on teams whose coaches reported that they were not performing the program. Teams performing the program also experienced 17 percent fewer match injuries and 19 percent fewer training injuries relative to their own experience of four years earlier (Junge et al., 2011). Thus, it is possible to develop a sport-specific neuromuscular training program, implement it on a large scale, and achieve a demonstrable favorable effect on injury outcomes. Comparable success was achieved with a neuromuscular warm-up program similar to the 11+ among 1,500 girls participating in high school basketball and soccer in Chicago. About half of the 95 coaches in the study were randomly assigned to a control condition, and the remaining coaches were randomly assigned to the intervention group. Coaches in the control group used their usual warm-up, whereas coaches in the intervention group re- ceived two hours of instruction on how to implement a 20-minute neuromuscular warm-up program with their players; they were also given a DVD and printed materials with specific information about the program. Interventiongroup coaches reported that they used the prescribed warm-up in more than 80 percent of their training sessions. As compared with controlgroup players, players in the intervention group experienced 65 percent fewer gradual-onset lower-extremity injuries; 56 percent fewer acute-onset, noncontact, lower-extremity injuries; and 66 percent fewer noncontact ankle sprains (LaBella et al., 2011). Thus, in this study, as with the 11 program in Switzerland, a minimal neuromuscular training intervention exerted a substantial favorable effect on the occurrence of sport injury (for more on this topic, see this chapter’s Focus on Application sidebar). Equipment Until the past decade, equipment interventions were the most studied form of sport injury prevention (Klügl et al., 2010; McBain et al., 2011). Preventive activities in this category focus on getting athletes to play on safer surfaces (e.g., gymnasium floors) or use protective equipment (e.g., helmets, mouth guards) or devices (e.g., braces, orthotics). The impetus to get athletes to play on certain surfaces (and not on others) comes from research showing that injury rates vary as a function of playing surface. For example, one study found that ACL injuries in female team handball players occurred with greater frequency on floors with artificial surfaces than on floors with wooden surfaces (Olsen, Myklebust, Engebretsen, Holme, & Bahr, 2003). In another study, when high school American football players competed on FieldTurf rather than on natural grass, they sustained more low-severity noncontact injuries, muscle injuries, surface or epidermal injuries, and injuries in high temperatures but fewer short-term injuries (one- to two-day time loss), long-term injuries (22 or more days of time loss), head or neural injuries, and ligament injuries (Meyers & Barnhill, 2004). B.W. Brewer and C.J. Redmond, Psychology of Sport Injury, Champaign, IL: Human Kinetics, 2017). For use only in Psychology of Sport Injury Course 1–Sport Medics.