Understanding Youth Sport Coaches' Perceptions of Evidence-Based Injury-Prevention Training Programs: A Systematic Literature Review

Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) method,⁴²  we identified studies focused on the knowledge, attitudes, and beliefs of youth sport coaches regarding injury-prevention training programs and their implementation. As the study is a scoping review, no protocol was required to be registered with the International Prospective Register of Systematic Reviews (PROSPERO). In November 2021, one author (L.E.H.) completed an electronic database search of the literature. Results were limited to articles printed in English. The search was conducted using PubMed and Google Scholar and combinations of the following search terms: knowledge, attitude, belief, injury prevention program, youth, sport, ACL, and lower extremity. Attitude is defined by the Oxford dictionary as “a settled way of thinking or feeling about someone or something, typically one that is reflected in a person's behavior.”⁴³  As this definition correlates closely with the Belief domains of the TDF, we chose attitude as a search term to ensure inclusion of all relevant articles.

We merged studies in which researchers reported on data from the same datasets and removed duplicate studies. To qualify for inclusion, studies must have been printed in English and published in a peer-reviewed journal. Unpublished manuscripts and conference abstracts were excluded. Inclusion was not limited by year of publication. A critical appraisal was not conducted. No specific study design was targeted in order to include all results. When a specific age was missing but the authors stated participants coached “youth” or “adolescent” athletes, we assumed the athletes were under 18 years old. To meet the inclusion criteria, investigators must have evaluated the knowledge, attitudes, beliefs, contextual perceptions, or all 4 of youth sport coaches regarding ACL injury-prevention training programs. If an intervention was provided to educate implementers about injury-prevention training programs, we examined only the knowledge, attitude, belief, and contextual perception responses before the intervention, as we were interested in baseline measures.

After the database search, we reviewed the titles and abstracts and excluded those that did not pertain to injury-prevention efforts. Full texts of the remaining articles were retrieved. Upon a full-text review, those articles that did not pertain to the lower extremity; did not address ACL injury-prevention training programs; did not include coaches' knowledge, attitude, beliefs, or contextual perceptions; or were not specific to youth sports were excluded. Sixteen articles qualified for inclusion. A citation search of the original 16 articles was completed by the first author (L.E.H.), who identified additional titles to be retrieved for assessment of eligibility. Of these titles, and following the same exclusion criteria, 3 additional articles were deemed eligible for the review. A total of 19 studies were included in our final review, which was agreed upon by 2 authors (L.E.H. and D.A.P.).

Information on authors, study design, location (country in which the study was performed), sport, level of play, injury-prevention training program used (if applicable), and implementation framework or behavioral theory used was charted.

Implementation frameworks are used to support the application of evidence-based practices and often consist of processes and factors that are important to consider throughout the implementation process.⁴⁴  For the purposes of this review, we charted implementation frameworks to gauge the general use and variety of frameworks used when evaluating the application of ACL injury-prevention training programs. Health behavior refers to “actions of individuals, groups, and organizations as well as those actions' determinants, correlates, and consequences,” and may also include the measurable “mental events and feeling states” of individuals.⁴⁵  Behavioral theories are used to understand health behavior and were therefore of interest in this literature review.

The terms youth and adolescent were used interchangeably in this review to indicate those under 18 years of age. Competitive level was characterized as the level stated in the original study. Researchers of the original studies used terms such as school or high school, club, elite, grass-root, amateur, and youth or adolescent to label the level of competition. For this review, if the level was identified with the word school, we considered it a school-organized activity. All other identifiers were considered independently organized sport.

The charted data were organized and summarized using the following 4 domains of the TDF: Knowledge, Beliefs About Capabilities, Beliefs About Consequences, and Environmental Context and Resources. Although additional domains (eg, Skill, Professional Role, and Social Influences) are also important, few to no evaluations of these domains were available in the included population, perhaps indicating a need for future evaluation of these factors.

The TDF defines knowledge as “an awareness of the existence of something.”³⁷  Beliefs are categorized into 2 separate domains, namely, Beliefs About Capabilities and Beliefs About Consequences. Beliefs About Capabilities is defined as an “acceptance of the truth, reality, or validity about an ability, talent, or facility that a person can put to constructive use.”³⁷ Beliefs About Consequences is defined as “acceptance of the truth, reality, or validity about outcomes of a behavior in a given situation.”³⁷  Factors outside the individual, including features of the context in which he or she lives and works, can also affect implementer perceptions. This defines the TDF domain of Environmental Context and Resources.³⁷  Responses were categorized into each of the domains based on whether they fit the constructs associated with the domain or aligned with the domain's guiding questions. The domains, constructs, and associated questions can be found in Table 2.

The strategy used for searching, screening, and inclusion per the PRISMA-ScR guidelines is depicted in Figure 1.⁴²  The 19 studies consisted of responses from 4191 sport stakeholders, of whom 2473 were youth sport coaches (age = 18–66 years; sex = 629 males, 196 females, 1648 not reported by the study authors; coaching experience = 1–40 years). Only a few investigators described coach demographics that affect social determinants of health. Four groups addressed coach education levels,^27,46–48  2 noted the rural or urban nature of teams,^27,49  and only 1 provided the race or ethnicity of coaches.⁴⁶  Stakeholders who did not identify as coaches included fitness coaches (n = 4), physiotherapists (n = 5), parents (n = 292), and athletes (n = 1417). Responses from athletes and parents who did not serve as coaches were excluded. O'Brien and Finch⁴¹  did not separate responses according to participant role; therefore, the views of fitness coaches and physiotherapists were included in the results. All 19 groups evaluated knowledge and beliefs, and 13 groups^{27,28,40,46–55}  evaluated environmental context and resources.

In 11 studies, researchers assessed knowledge or beliefs regarding general ACL injury-prevention programming^*; in 5, they asked specifically about the Federation Internationale de Football Association (FIFA) 11+^{39,41,48,49,55} ; and in 3, they considered other injury-prevention training programs (ie, Activate,⁶⁰  Knee Control,⁵⁰  and Knokl for dit knæ⁴⁰). A behavioral theory (Health Belief Model^{40,41,46,50,58} [n = 5]; Theory of Planned Behavior/Reasoned Action^28,39,57,58 [n = 4]; Transtheoretical Model⁴⁶ [n = 1]); or implementation framework (Reach, Effectiveness, Adoption, Implementation, Maintenance [RE-AIM]^{39–41,49,51,56,58} [n = 7]; Health Action Process Approach^47,48,59,60 [n = 4]; Predisposing, Reinforcing, and Enabling Constructs in Education/Ecological Diagnosis & Evaluation [PRECEDE]/Policy, Regulatory, and Organizational Constructs in Educational & Environmental Development [PROCEED]⁵² [n = 1]) was applied in 16 of the 19 studies, indicating widespread use of both behavioral theories and implementation frameworks to understand the function of ACL injury-prevention training programs. Diversity of frameworks and theories was lacking, as only 3 frameworks and 3 theories were used.

Most investigations (n = 16) focused on youth soccer or basketball.^{27,28,39,41,46–52,54–58}  Thirteen studies were conducted outside the United States.^{39–41,47–51,54–56,59,60}  Of the 6 studies conducted within the United States, 4 examined high school alone^28,46,52,57; 1 examined solely club (U9–U19)⁵⁸ ; and 1 looked at club, high school, and collegiate (U12–college age) athletes.²⁷  In many studies (13), the knowledge, beliefs, or contextual perspectives of coaches engaged in independently organized sport were evaluated.^{27,39–41,47–51,54–56,58}  Nearly half (n = 8) examined school-organized athletics.^{27,28,46,47,52,57,59,60}  Two included coaches from both settings.^27,47  The studies and study characteristics are described in Table 3.

Coaches were generally lacking in knowledge of injury-prevention training programs. Specifically, they lacked knowledge of the TDF constructs of knowledge of condition or scientific rationale and procedural knowledge (see Table 2). Findings in the construct of knowledge of condition or scientific rationale included a lack of knowledge about knee injuries or injury prevention^{39,46,50,51,54,56,58}  and the existence of injury-prevention training programs.^{28,40,49,55,56}  Findings in the construct of procedural knowledge included a lack of knowledge about appropriate exercises to include^{47,49,52,54,59}  and implementation of injury-prevention training programs.^27,40,49 

Although some coaches were aware of the injury risk among youth athletes,^41,48  that knowledge was inconsistent^50,51,54  and varied depending on the age and sex of the athletes with whom coaches interacted.^28,39,58  Additionally, coaches were not aware of the long-term health effects an ACL injury can have on a youth athlete.⁵⁸  Just over half knew of the decreased injury risk associated with injury-prevention training programs.^27,58  Coaches who attempted to increase their knowledge did so in several ways, including learning from other coaches^{40,47,49,50,52}  or from health care providers,^47,54  attending courses,^{40,47,49–52,57}  and relying on personal experience.^27,47,51,52 

Coaches' perceptions of injury risk fell under the TDF domain Beliefs About Consequences. Few coaches perceived lower extremity injuries to be a problem for their teams.²⁸  Some coaches did not anticipate their athletes would be injured in the near future^46,59  and believed that if they did, it would be due to “bad luck.”⁴⁰  A subset of coaches did not believe their athletes would sustain knee injuries, most believed that knee injuries were preventable, injury prevention was important, and injury-prevention training programs would assist in lowering the injury risk.^† Although coaches generally believed that injury-prevention training programs would reduce the injury risk, others were looking for statistical assurance that injury-prevention training programs reduced injury, improved performance, or both.^{27,28,40,51,58} 

A coach's perception of his or her ability to reduce the injury risk falls under the TDF domain Beliefs About Capabilities. Coaches displayed positive perceptions of injury-prevention training programs^56,57  and believed that injury prevention was their responsibility,^39,40,53  yet many expressed doubt about their ability to implement these programs. De Ste Croix et al⁵⁶  found that only about a quarter of European grass-root soccer coaches self-identified as confident to deliver injury-prevention training to their youth athletes. Interviews with 12 southern California high school coaches highlighted a lack of confidence in their ability to choose exercises, properly order them, and adequately teach their athletes how to perform them.⁵²  Researchers in 1 study noted that most coaches (78%) displayed high self-efficacy scores; however, only 25.2% of the same sample demonstrated high injury-prevention knowledge scores.⁴⁶ 

Findings pertaining to coaches' contextual perceptions fell under the TDF constructs of resources or material resources, environmental stressors, organizational culture or climate, and barriers and facilitators (Table 1). Currently, coaches individually research injury prevention and injury-prevention training programs, which results in information obtained from various sources, not all of which is correct or up to date.^{39,40,47,51,52,54}  Coaches also cited a lack of time,^{27,28,48,49,52}  space,^48,52  athlete interest,^28,48,52  support,^46,51  and resources^28,46,48  as barriers to implementation. Investigators in 2 studies^27,40  observed that coaches unanimously agreed that education on injury prevention and injury-prevention training programs should be an essential part of coach education or licensure. Although 84% of coaches said they could access injury-prevention information, only a third said coaching courses included information about injury risk and interventions, and half of those with access to information stated that their clubs were not advocates for interventions or sources for awareness.⁵¹  Additionally, coaches cited a lack of training, administrative support, and availability of materials as factors influencing their use of injury-prevention training programs.^46,50,56 

The aim of our scoping review was to explore and summarize the current literature regarding youth sport coaches' knowledge, attitudes, beliefs, and contextual perceptions of injury-prevention training programs. We organized these findings within the TDF. Coaches displayed largely positive attitudes toward injury-prevention training programs and believed they could reduce injury (Beliefs About Capabilities and Beliefs About Consequences domains), but large gaps in coach knowledge persisted (ie, constructs of general knowledge and procedural knowledge). Additionally, the effects of environmental context and resources on implementation were not evaluated as frequently as knowledge, attitudes, and beliefs, and when they were assessed, important factors related to social determinants of health were often left out.

Based on these results, we are the first to demonstrate that information about the effectiveness of training programs to prevent ACL injury has not reached youth sport coaches. These coaches are charged with training young athletes whose risk of injury has risen exponentially in recent years.⁴  Our findings also indicate varied degrees of knowledge among coaches about risk factors for and consequences of an ACL injury, as well as the interventions available to reduce risk and how to successfully implement them. Developing mechanisms to broaden coaches' knowledge of the effect that participation in an ACL injury-prevention training program can have on their athletes is essential.

Use of the TDF and associated frameworks is a viable option to aid in the development of such mechanisms. The TDF creators, namely, Susan Michie and her research team,⁶¹  also identified specific behavioral change strategies to address the barriers and facilitators in each domain. These strategies can be further developed into interventions through the use of the Michie et al⁶² COM-B framework and Behavior Change Wheel. Developers of the COM-B suggested that 3 conditions, namely, capability, opportunity, and motivation (COM), can be used to influence behavioral (B) change. This technique of mapping strategies to TDF domains has been successful in a school setting. After the barriers, TDF domains in which they fell, and application of appropriate intervention strategies were identified, researchers^63–65  found increases in overall compliance with a nutrition program in Australia. Based on the barriers we identified in this review, potential intervention strategies based on the Michie guides include those that provide information regarding behavior and its outcomes, increase and rehearse skills, and provide feedback. All of these strategies could be taught through coach education programming.

Injury-prevention education for coaches was suggested by a number of authors.^{40,48,50,55–57,60}  Investigators in 4 studies^27,46,51,54  went so far as to propose policy changes mandating the incorporation of such information in coach education and licensure requirements. Injury-prevention education programs have been effective strategies in the past. After an educational intervention, coaches were successful in delivering an injury-prevention training program consistently to their teams.^27,66–68  Switzerland and New Zealand were successful in implementing injury-prevention training programs countrywide^69,70 ; however, such an undertaking would be considerably more difficult in a country the size of the United States with less cohesive youth sports organizations. Targeting individual coaching associations or school districts instead may be more feasible.

Athletic trainers are in ideal positions to deliver such train-the-trainer education to coaches. Although it is difficult for secondary school athletic trainers to reach every team every day, they do have established, trusting relationships with coaching staffs. Athletic trainers are health care providers who are experts in injury prevention and reliable sources of injury-prevention information. Training coaches to deliver injury-prevention training programs allows information to be delivered more widely to student-athletes, with little increased demand on athletic trainers' already limited time. Providing athletic trainers with intervention strategies that coaches find acceptable, appropriate, and feasible will be important if we are to make the most of this opportunity.

Previous researchers^69,71  suggested that educational programs appeal most to coaches when their individual experiences are acknowledged and appreciated and the material is delivered in a “propose” rather than “impose” manner, allowing coaches to adapt the program to their sport and team needs. Additionally, coaches place a great deal of importance on practical, field-type experiences and training, as it applies to both injury-prevention education^27,48,50,56  and general coach education and development.^71,72  Just as important is the opportunity for coaches to interact with and learn from each other. Mentoring is a crucial piece of a coach's development; therefore, allowing time to practice skills together, receive critiques from peers rather than program implementors, and engage in critical thinking with like-minded colleagues to troubleshoot common barriers is essential.^48,71–73  Packaging injury-prevention information appropriately may increase its appeal to coaches. Furthermore, providing accessible and applicable injury-prevention education to youth sport coaches takes the onus off coaches to find and determine what information can be trusted.

Here, we demonstrated that coaches believe injury prevention is important and that injury-prevention training programs work. However, if they do not believe their athletes will experience ACL injuries, implementation remains in question. Although McKay et al³⁹  found no correlation between coaches' knowledge and beliefs about injury risk and prevention and team adherence to injury-prevention training programs, they did suggest that injury-prevention programs should be tailored to the needs and motivations of the intended audience. Conversely, Møller et al⁴⁰  identified that beliefs and attitudes, along with experiences, about injury risk and prevention affected injury-prevention training program uptake and posited that these factors should be better understood by program developers. Continued research is needed in this area to further clarify beliefs about injury risk (TDF domain of Beliefs About Consequences) and injury-prevention training programs that contribute to implementation decisions.

Of the investigations included in this review, researchers of 5 studies^{46,48,51,52,56}  evaluated self-efficacy and its effect on implementation or planned implementation. It is important to note that self-efficacy is a construct in the TDF domain of Beliefs About Capabilities and thereby influences implementation. In 1 study,⁴⁶  the authors reported high levels of self-efficacy among 78% of coaches, and yet, 75% of coaches displayed poor injury-prevention knowledge scores. This information indicates that, in some cases, coaches may not be applying appropriate injury-prevention strategies, highlighting the need for better knowledge translation from research to practice in this population. Self-efficacy, although important, is insufficient to ensure appropriate implementation. In Spain, where 37% of coaches expressed confidence in their ability to implement programs, implementation remained around the 20% mark (22%).⁵⁶  Similarly, Frank et al⁷⁴  discovered that soccer coaches' intent to implement injury-prevention training programs did not result in actual implementation. Future researchers should continue to hone the use of behavioral theory, not just as a postintervention measure but in the creation of the intervention itself. Application of the COM-B model and Behavior Change Wheel⁶²  lends itself well here. As the authors of the studies included in this review described, creating tailored interventions that address the needs, motivations, and perceived barriers of coaches is important^{41,48,49,51,52,60}  and currently missing in the United States.

Along with addressing the individual factors that affect implementation, more exploration is required to fully understand the effect of environmental context on the implementation of injury-prevention training programs. Historically in sports medicine, we have thought of ACL injury-prevention training program implementation as a 1-phase process. As researchers realized that evidence-based ACL injury-prevention training programs were not being used, much work was done to understand barriers to and facilitators of (Environmental Context and Resources domain constructs) program implementation. Despite the recognition of common barriers (lack of time, knowledge, and resources^{28,48–50,52,56}) and common facilitators (administrative support, access to education programs, and confidence in the ability to deliver programs^27,40,50,55), few investigators have evaluated viable implementation strategies to address these barriers and facilitators. The identification and development of implementation strategies and preparing implementors for the injury-prevention training program are phases we have failed to target in the larger implementation context.

The use of implementation science strategies is supported in the realm of sports injury prevention,^75–77  and the field of implementation science offers an array of frameworks to help tackle gaps in the current implementation procedure. Nilsen⁷⁸  identified several categories of implementation theories, models, and frameworks that provide guidance for choosing the appropriate framework for the task at hand. Nilsen's categories included process models, determinant frameworks, classic theories, implementation theories, and evaluation frameworks.⁷⁸  Some of these frameworks and theories have already been used in an injury-prevention context. For example, RE-AIM,⁷⁹  PRECEDE/PROCEED,⁸⁰  and the Consolidated Framework for Implementation Research (CFIR)⁸¹  have all been applied to evaluate barriers to and facilitators and implementation of ACL injury-prevention training programs.^34,49,52  Moreover, Padua et al³¹  and Finch et al^32,82  provided the injury-prevention community with process models specific to our context. The field of injury prevention would benefit by broadening our use of implementation frameworks beyond process and evaluation. As both CFIR and TDF fall under determinant frameworks and address domains of concern identified through this literature review, their use in future research may be helpful.

A gap in the literature about identifying the motivations, needs, and priorities of school-organized, youth sport coaches in the United States remains. One reason for this lack of attention in the United States may stem from the largely decentralized structure of youth sport. Whereas the United Kingdom and other European countries have organized youth club soccer so that organizations are under the same umbrella, this is not the case in the United States. Some teams are associated with organizations such as USA Basketball and the US Soccer Federation, but countless independent clubs and Amateur Athletic Union organizations, in addition to middle and high school teams, provide opportunities for youth athletes to play. This decentralized structure makes it more difficult to gather information and also decreases the applicability of injury-prevention training programs as well as coach education programs. As sport is such an important part of the culture in the United States, we need to make sure young athletes are participating safely, regardless of the organization in which they play. The wide variety of organizations, coaches, and athlete needs makes it all that much more important to understand the context, needs, and motivations to help facilitate successful implementation of injury-prevention training programs.

The use of a determinant framework focused on individual domains, such as the TDF, will be helpful in organizing constructs contributing to the decision to implement ACL injury-prevention training programs. Our synthesis of the available evidence revealed coaches' disappointment in the lack of support, resources, and time related to the implementation of injury-prevention programming as well as their inability to access injury-prevention education (Figure 2).^{39,41,46,49,56}  Reaching coaches of all athletes, regardless of race, location, and socioeconomic status, is necessary to ensure nondiscriminatory access to injury-prevention training programs, which can then influence equitable quality of life post–sport participation.

A limitation of the studies fitting the inclusion criteria for our scoping review was the lack of information regarding coaches' race or ethnicity, the rural or urban nature of the teams they coached, the socioeconomic status of the area in which they coached, and the level of education of the coaches themselves. As such, in future examinations, pairing the TDF with another determinant framework that considers constructs outside the individual, such as CFIR, will assist in addressing those concerns. Additionally, most of the studies that qualified for this review were conducted in high-income countries, focused on sport organizations classified as elite, top tier, or of the highest level and primarily included coaches of male basketball and soccer teams. Future authors should evaluate the knowledge, beliefs, and perceptions of coaches located in nations of different income levels who work with lower-level athletic organizations across sport and gender categories to ensure the appropriate development of intervention strategies.

Our study was not without limitations. As a systematic scoping review, it was not eligible for registration with PROSPERO. Also, due to the nature of scoping reviews, no critical appraisal of the studies was conducted. Except for these limitations, the remainder of the items on the PRISMA-ScR checklist were addressed and reported (see Supplemental Table, available online at 10.4085/1062-6050-0215.22.S1). Furthermore, although only 1 author (L.E.H.) performed the database search and initial extraction of studies, final inclusion was confirmed separately by 2 authors (L.E.H. and D.A.P.).

The integration of implementation science strategies in the area of injury prevention remains a new concept with much opportunity to expand the field and develop a greater understanding of their interplay. Researchers thus far have primarily used implementation science frameworks in an evaluative manner. Additionally, although researchers have been successful in the identification of appropriate components of injury-prevention training programs, less has been done to prepare coaches for implementation. Athletic trainers, once equipped with effective strategies, are perfectly positioned to prepare and assist coaches in delivering programs. Moving forward, it is important to understand diverse, American youth sport coaches' readiness to implement and integrate determinant frameworks to identify domains that should be attended to. Strategies used to address readiness for and barriers to implementation should align with identified domains of determinant frameworks and be rooted in behavioral change techniques.

Supplemental Table. Preferred Reporting Items for Systematic Review and Meta-Analysis Extension for Scoping Reviews (PRISMA-ScR) Checklist.

Found at DOI: http://dx.doi.org/10.4085/1062-6050-0215.22.S1