Table 2.

Barriers to implementation with citations from studies.

Barrier	Study quotes
Motivation	“Most of the 12 teams that declined to participate after learning about the preventive program expressed skepticism regarding the usefulness of the program as the reason for nonparticipation, which suggests a different attitude toward preventive training.” (Kiani et al.,26 2010, p. 44) “Considerable efforts were made to motivate the intervention teams to include the exercise program as a standard part of their training program. Instructors visited the teams three times during training at the start of the study and again after the summer break, and the teams received balance mats and a brochure detailing the intervention program. Despite this, the intervention teams included the injury prevention program in only 60% of their training sessions during the first half of the season…” (Steffen et al.,36 2008, p. 609) “As we discovered, implementing these types of exercise studies can be challenging because many coaches are unwilling to modify their practice protocols.” (Pfeiffer et al.,34 2006, p. 1773) “Furthermore, it might be difficult to motivate the subjects to perform the training as prescribed and to maintain their motivation at a high level throughout the study period. Therefore, in this investigation the authors (K.D. and S.W.) were in regular contact with the players to try to keep them motivated to perform the balance board training as prescribed. (Soderman et al.,35 2000, p. 361) “…all of the 10 exercises were to be carried out during every 15-min training session, generally without progression or variation. This may have resulted in reduced motivation among coaches and players.” (Steffen et al.,36 2008, p. 611)
Time requirements	“…during the competitive season, many of the teams in the present investigation often trained only once or twice weekly. As a consequence of these factors, the ability to include preventive training sessions on a consistent basis may have been limited.” (Steffen et al.,36 2008, p. 611) In the beginning of the present study many coaches were not convinced that the exercises suggested in the initial program may help to prevent injuries. Instead they were concerned that the exercises would steal valuable preseason training time. (Petersen et al.,33 2005, p. 620) “In an effort to design an effective program to prevent noncontact ACL injuries that could readily be used at many levels of play without significant investment in equipment or time, an expert panel was convened by the Santa Monica Orthopedic and Sports Medicine Research Foundation in 1999. This group designed the Prevent injury and Enhance Performance (PEP) Program.” (Gilchrist et al.,37 2008, p. 1477)
Skill requirements	“In the intervention a strong emphasis was placed on proper technical performance of every exercise. We considered it important that the intervention coaches and players had good knowledge of the correct training technique, typical mistakes in each exercise manoeuvre, and appropriate methods for their correction.” (Pasanen et al.,29 2010, p. 6) “During the practical demonstration of the exercises, study therapists instructed the coaches carefully on how to clear player to progress to the next level of difficulty—that is, when all repetitions were performed with good neuromuscular control, mainly focusing on core stability and proper knee alignment.” (Walden et al.,30 2012, p. 2) “The instructors had been familiarized with the programme during a two hour seminar, in which they received theoretical and practical training on how to conduct the programme.” (Olsen et al.,24 2005, p. 2) “Older, overweight, and less physically fit coaches tended to include fewer exercises, suggesting that they may have omitted exercises that they could not demonstrate themselves. Compliance may improve if each coach brings an athlete to the training session to learn demonstration of the exercises.” (LaBella et al.,27 2011, p. 1038)
Compliance	“In conclusion, we observed no effect of the injury prevention program on the injury rate, most likely because the compliance with the program was low.” (Steffen et al.,36 2008, p. 605) “We were somewhat surprised by the low compliance in the study because the problem of ACL injuries has received a lot of attention from the media and within the handball community. Despite the high incidence of injury, the dire future consequences to knee function in injured players, and close follow-up of the teams by physical therapists, acceptable compliance was achieved in less than half of the players.” (Myklebust et al.,32 2003, p. 76) “Older, overweight, and less physically fit coaches tended to include fewer exercises, suggesting that they may have omitted exercises that they could not demonstrate themselves. Compliance may improve if each coach brings an athlete to the training session to learn demonstration of the exercises.” (LaBella et al.,27 2011, p. 1038) “The high compliance rate in this study suggests that the program is easy to implement and incorporate into regular soccer practice.” (Kiani et al.,26 2010, p. 49)
Cost	“The cost of training a group of 15 to 20 coaches was $80 per coach.” (LaBella at al.,27 2011, p. 1036) “In an effort to design an effective program to prevent noncontact ACL injuries that could readily be used at many levels of play without significant investment in equipment or time, an expert panel was convened by the Santa Monica Orthopedic and Sports Medicine Research Foundation in 1999. This group designed the Prevent injury and Enhance Performance (PEP) Program.” (Gilchrist et al.,37 2008, p. 1477)

Abbreviation: ACL = anterior cruciate ligament.