Factors Influencing the Implementation of Anterior Cruciate Ligament Injury Prevention Strategies by Girls Soccer Coaches : The Journal of Strength & Conditioning Research

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Factors Influencing the Implementation of Anterior Cruciate Ligament Injury Prevention Strategies by Girls Soccer Coaches

Joy, Elizabeth A.; Taylor, John R.; Novak, Melissa A.; Chen, Michael; Fink, Barbara P.; Porucznik, Christina A.

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Journal of Strength and Conditioning Research 27(8):p 2263-2269, August 2013. | DOI: 10.1519/JSC.0b013e31827ef12e
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Soccer is one of the fastest growing team sports in the United States. Its increasing popularity is largely because of its accessibility and relative safety as a sport. These characteristics have helped soccer become the fourth most popular high school sport in terms of participation for both boys and girls (5). In the 2007–2008 school years, 383,561 boys and 346,545 girls played on high school teams across the country (5). The rise in the number of woman players is largely responsible for the growth. According to the Sporting Goods Manufacturers Association, the percentage of frequent woman players—those who played at least 52 days per year—was 28% in 1987. In 2008, the quantity increased to 56% (3). One downside to this growth in participation is that woman soccer players are 3 times more susceptible to tearing their anterior cruciate ligament (ACL) than their man counterparts (15). The disparity in injury rates is particularly interesting to health care and sports medicine professionals in Utah because the state has one of the highest rates of soccer participation among youth in the United States (13). According to the Utah Youth Soccer Association (UYSA), in 2009, 17,280 of the 36,000 participants (48%) were woman (4). This makes Utah an optimal location for evaluating and further studying ACL injury in woman athletes related to soccer participation.

ACL injury has a profound impact on athletes. In addition to losing a significant amount of time from competition, ACL injury may bring a heavy financial and emotional burden as well. The average time for an athlete, who tears his or her ACL to return to play, is 6 months (7). Total surgical repair and rehabilitation costs can exceed $10,000, with average patient out-of-pocket expenses of $2,300 or more (1,8,10). In addition to this financial burden, it has been reported that the emotional stress from the injury may negatively impact student academic performance and place them at higher risk of developing depression (9,11).

The majority of ACL tears in woman soccer players occur through noncontact mechanisms. The mechanisms often include but are not limited to change of direction or cutting maneuvers combined with deceleration, landing from a jump in or near full knee extension, and pivoting with the knee near full extension and the foot planted (2). Multiple studies have evaluated the effect of adding neuromuscular training programs specifically designed to reduce ACL injuries to the athletes’ training regimen (10–15). The results of these studies have been encouraging and demonstrate that neuromuscular training—including strengthening and flexibility exercises, plyometrics, agility, balance, technique training, and heightened awareness of the biomechanics of injury—reduces ACL injury risk in woman athletes (10,11). In addition, a recently published systematic review of injury prevention training programs found that there is moderate evidence to support the use of multifaceted interventions as effective in the prevention of ACL injuries in woman athletes (17).

Despite promising evidence that prevention programs are effective in reducing the incidence of ACL injury, ACL injury prevention is not fully embraced by soccer coaches, and the proportion of coaches at all levels of competition (club, high school, or collegiate) who have implemented such a program is unknown. Reported barriers to incorporating ACL prevention programs into routine practice and conditioning by coaches include lack of knowledge about ACL injury as a preventable condition, competing time demands, a perceived lack of expertise in implementing such a program, and insufficient benefits (i.e., a perceived lack of performance benefit) (6). Incomplete or partial implementation of an ACL IPP or poor compliance by coaches and athletes will not decrease the ACL injury rate (11). To overcome these barriers and improve compliance, we believe that identifying a “best practice” approach will provide us with greater understanding of those factors that promote successful implementation of prevention programs by soccer coaches. In turn, this will assist us in disseminating, implementing, and evaluating evidence-based ACL IPPs in community settings.

There are 3 specific aims of this study. The first aim was to determine the proportion of soccer coaches who have implemented an ACL IPP. We hypothesize that a small percentage of respondents will have implemented an ACL IPP. The second aim was to identify those factors influencing the ability and willingness of a coach to implement a program. We hypothesize that various factors, such as coaching licensure, personal history of ACL injury, and team location (urban, semiurban, and rural), will predict that coaches are most likely to have implemented an ACL protection program. These predictor variables were selected based on literature, suggesting that coach characteristics predict knowledge of sports injury prevention (15,16). The third aim was to identify best practice coaches in the state of Utah, i.e., those implementing an appropriate ACL prevention program.


Experimental Approach to the Problem

This is a cross-sectional study of Utah girls soccer coaches, coaching players from ages U12 (players at least 11 years of age, but younger than 12 years at the start of the soccer season) up though the collegiate level, including club, high school, and university-level coaches.

Our main outcome measure was the presence of an ACL IPP. Predictor variables included level of competition coached; coach age, gender, and education level; coaching licensure; coach’s highest level of competitive play; team location (defined as urban, semiurban, and ural); number of ACL injuries on the team; and coach or coach family member with ACL injury (15,16).

The survey was then followed by a qualitative study in which best practice coaches—coaches who met criteria for implementation of ACL IPPs—were interviewed via telephone.


Institutional Review Board (IRB) approval for the study was obtained from the University of Utah and appropriate consent was obtained pursuant to the law (IRB 00033623). Collegiate coaches (n = 7) were identified from school web sites; high school coaches (n = 100) were identified through the Utah High School Activities Association; and club coaches (n = 649) were identified with the assistance of the UYSA.


Survey data were collected from June 2009 through December 2009. A link to the Web-based survey was sent directly to UYSA coaches from the association and was accompanied by a cover letter from UYSA encouraging participation. High school and college coaches received an e-mail including a link to the survey directly from the principal investigator. In addition to e-mail distribution of the questionnaire, paper copies were distributed to club coaches at soccer tournaments and coach licensing certification courses through the UYSA. Responses to the hard copies were manually added to the database. No controls were used in this study because of the study design.

Efforts to enhance the response rate included (a) resending the survey via e-mail at regular intervals (every 2 weeks for 5 cycles), (b) phone calls to coaches reminding them to complete the online survey, and (c) encouragement from soccer club directors to their coaches to complete and return the online survey.

Completion and return of the survey signified consent to participate. At the conclusion of the survey, subjects were asked if they would participate in a brief telephone interview. If selected to take part in this phase of the study, study personnel called and asked participants to consent again after which a copy of the consent was mailed to them.

Coaches who responded affirmatively to the question, “Do you have a training program specifically aimed at ACL injury prevention?” and acknowledged that incorporation of at least 3 of 5 program elements (i.e., providing immediate feedback on technique, inclusion of hamstring strengthening, cutting drills, balance training, and core stabilization) were determined to be best practice coaches.

Best practice soccer coaches were asked to participate in a telephone interview to gain further insight regarding their education and knowledge of prevention programs, barriers faced, and implementation strategies. A single investigator conducted telephone interviews from November 2010 through February 2011.

In appreciation for their participation, all coaches who completed and returned the initial survey were mailed a DVD of the Santa Monica Prevent Injury and Enhance Performance Program. The DVD provides coaches with information (pictures, video, and instructional text) regarding implementation of a research-tested ACL IPP designed specifically for woman soccer players.

Statistical Analyses

Statistical analysis of the survey and telephone interview data were performed using SAS version 9.2 (SAS Institute, Cary, NC, USA). The a priori hypothesis was that best practice coaches would differ in some measurable aspects of demographics, education, and experience from other coaches. Identifying these differences could lead directly to delivery of education or tools intended to enhance adoption of ACL prevention programs among all coaches. For example, we compared the coaches’ own level of play experience expecting that best practice coaches were more likely to have experience at the collegiate or higher level and have participated in ACL prevention programs themselves. Although experience level of the coach is not an easily modifiable factor, coaches lacking such experience could be targeted for clinics or additional training in how to incorporate ACL prevention programs into their routine.



Coach participation is illustrated in Figure 1. Seven hundred fifty-six coaches were invited to take part in the study. Response rates for the survey were 71% for college/university coaches, 56% for high school coaches, and 12% for club coaches.

Figure 1:
Flow of participants in the study.

Coaches responding to the survey are described in Table 1. Coaches are divided into implementers and nonimplementers and further stratified by competitive level (club, high school, and college), team location (urban, semiurban, and rural), professional education, and competitive playing experience. Both implementers and nonimplementers had very similar responses across most of the variables measured in the study. Implementers had a higher level of education, a higher level of personal playing experience, and had a higher incidence of ACL injuries on their team than nonimplementers.

Table 1:
Characteristics of the study population.*

Only 19.8% of respondents have implemented a team ACL IPP. Of those implementing a program, 61% coached teams in an urban area, 36 % coached teams in a semiurban area, and 4% coached teams in a rural area. Sixty-eight percent of those that implemented an ACL IPP was man, 50% had ≥10 years of coaching experience, and 92% had postsecondary education.

Coaches with more than the median number of years coaching experience (7 years) were more likely to have an ACL IPP (odds ratio [OR] = 2.69, 95% confidence interval [CI] 1.1002–6.5850) than less experienced coaches. There was no association between having a prevention program and any other coach characteristics.

In univariate analysis, number of personnel (e.g., assistant coach, athletic trainer for the team) was correlated with the likelihood of reporting an ACL IPP (p = 0.0115). Specific types of support personnel were also associated with having an ACL prevention program. Teams that included a strength and conditioning coach had the greatest odds of having a prevention program (OR = 5.20, 95% CI 2.0176–13.4021) compared with teams lacking such an individual. Teams with more than 2 support personnel were also more likely to have a prevention program (OR = 3.04, 95% CI 1.23–7.55) than teams with fewer staff.

Logistic regression modeling was used to evaluate the concurrent association between coach and team characteristics. The model that best predicted (−2log L = 114.658) the odds of having a program included only presence of a coach with more than 7 years of coaching experience (OR = 2.425, 95% CI 0.949–6.195) and presence of a strength and conditioning coach (OR = 4.835, 95% CI 1.841–12.699).

Best Practice Interviews

There was unanimous agreement (n =14/14) among the coaches identified as best practice coaches that there are performance-enhancing benefits of ACL IPPs, education on ACL injury prevention should be required for licensure, and dissemination and implementation will require policy enactment within soccer associations.

At the high school level, best practice coaches believed that fewer coaches in their league were implementing an ACL IPP (14%) than actually are implementing (35%). In contrast, at the club level, best practice coaches overestimate how many of their peers are implementing (33%) versus the number of coaches actually implementing a program (12%).

Best practice coaches have identified several hurdles and challenges to implementing an ACL IPP. The most significant being lack of knowledge on how to implement an IPP along with how to give adequate feedback to athletes on injury prevention techniques—both of which were identified by 64% of the coaches. Time restrictions (43%) and getting athletes and parents to support the program (43%) were also barriers.

Best practice coaches overcame these hurdles and challenges in several ways. Many reported that having a positive attitude and acceptance of change regarding injury prevention (43%) were important in their ability to implement. Thirty-six percent of respondents pursued self-education and 29% reported efforts to educate parents and athletes on ACL injury prevention. The personal playing experience of coaches also contributed to successful implementation for 14% of respondents.

Influences prompting initiation of an ACL IPP by best practice coaches are represented in Figure 2. They were most notably influenced by injury prevention (93%) followed by performance enhancement (36%). A small percentage of coaches (14%) acknowledged an awareness of the higher risk of ACL injury in woman soccer players, which in turn lead to their efforts at injury prevention. Others felt pressure from parents to implement a program (14%) and others report being influenced because they knew someone (14%) who sustained an ACL injury as a result of soccer participation.

Figure 2:
Influences that promoted implementation of program.

Only 21% of best practice coaches use a validated ACL IPP, 14% use the Santa Monica Prevent Injury and Enhance Performance Program (12), and 7% use the Cincinnati Sports Metric Program (10). The majority of best practice coaches (79%) describe using a combined approach when implementing an ACL IPP.

Best practice coaches were also asked where and how they first obtained information on ACL injuries in soccer and more specifically ACL injury prevention while at a conference (29%), from a team parent who was often involved in health care (21%), or their own playing experience (21%). The majority of coaches (86%) followed up structured learning experiences by looking for information on the Internet. Likewise, these same coaches felt that they would benefit from further education through Web-based programs, DVDs, and conferences.

Nearly, all (13/14) the best practice coaches felt that the soccer organizations should be responsible for disseminating information on ACL injury prevention and most would personally advocate for ACL injury prevention education as a requirement for coaching licensure.


To date, implementation research regarding ACL IPPs in the United States has received little attention. The main finding of this study was that only a small proportion of girls soccer coaches in Utah (19.8%) have implemented an ACL IPP with their respective teams, despite the fact that ACL IPPs have growing support in the scientific literature. A consequence of this low implementation rate is a higher likelihood of preventable knee injuries in woman soccer players.

Through structured interviews with best practice coaches, we identified both modifiable and nonmodifiable factors that influence whether or not a coach will implement an ACL IPP with their team. Compared with nonimplementers, implementers were more likely to have higher level of education, higher level of personal playing experience, and higher incidence of ACL injuries on their team and were more likely to have an assistant coach, an athletic trainer, or strength and conditioning coach to assist with implementation.

In addition, information gathered from interviews provided insight regarding the knowledge, attitudes, beliefs, and behaviors of the coaches who successfully implemented an IPP with their athletes. Implementers further identified because best practice coaches seem to have a positive attitude toward implementing a prevention program accept change and believe that the program has performance-enhancing benefits that make their athletes better overall soccer players.

Best practice coaches are able to identify hurdles and overcome them. Many stated that once they realized the benefit of the ACL IPP for their woman athletes, they felt compelled to learn more about protecting their team. Knowledge is a hurdle best practice coaches identified as a challenge. Many of the coaches first obtained information on ACL injury while at a conference, from a team parent who was often involved in health care, or from their own playing experience—prompting a search for further information. Those interviewed feel that information should be more accessible and believe that the league governing body bears responsibility for dissemination of ACL injury prevention information. Despite their success in implementing a program, our best practice coaches felt that they would benefit from further education through Web-based programs, DVDs, and conferences/workshops specifically focused training on feedback recommendations.

Best practice coaches also felt that in addition to furthering their own knowledge on ACL IPPs, educating parents and athletes is the key to obtaining full and willing participation. These coaches were particularly motivated in sharing this information with athletes and parents, but many feel that it would be better for information to be systematically disseminated to athletes and parents by the soccer league.

There was unanimous agreement among best practice coaches that ACL injury prevention education should be required for coaching licensure similar to concussion education. The majority of these coaches felt so strongly about the need for ACL prevention education that they would be willing to personally advocate for this requirement being added to the licensure process.

Even among the identified best practice coaches, many use a combined prevention program and this may limit our ability to accurately assess outcomes for injury prevention. A minority of best practice coaches are implementing all components of a validated ACL IPP. Many of them tend to take bits and pieces from several different programs to meet their team’s needs depending on time constraints and/or availability of equipment. This indicates a continued need for education and knowledge enhancement even for those coaches who are doing their best.

Practical Applications

Because the body of knowledge supporting ACL IPPs grows, we need to identify how best to disseminate and implement this information. The goal was to prevent injuries in athletes whenever possible. A best practice approach promotes understanding of the most successful program implementations thus far while providing evidence for continued efforts in this area. Our data would suggest that to improve implementation of ACL IPP, it may be necessary to enact policy change within the soccer associations. Education on ACL injury prevention should be required for coach licensure. Demonstration and verbal feedback during soccer coaching workshops would also be a useful educational approach and a dissemination tool.


Funding for this project was provided by the American Medical Society for Sports Medicine Foundation. The authors of this article report no conflicts of interest. The results of the present study do not constitute endorsement of any products or programs by the authors or the National Strength and Conditioning Association.


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knee; athlete; education

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