Discussion

D2E has previously been shown to be efficacious in reducing risk factors associated with lower-limb injury.28 The reach of the current study expanded from the original efficacy study.28 Using coach training as a delivery platform; a key factor for effective translation of scientific evidence into practice,12 13 the capacity to reach a large number of junior community netball players that could not be reached otherwise was enhanced. In total, approximately half of junior players and coaches of junior players from the target age groups within an association were exposed to D2E.

Coaches' perspectives about the effectiveness of D2E indicated that the majority believed that it was effective in teaching junior players correct landing techniques and reducing their lower-limb injury risk. It is important to acknowledge that this implies that coaches were observing landing techniques that better matched D2E information and subsequently injury risk was reduced. In their opinion, D2E was also effective in improving players' athletic attributes and improving game-related skills, such as passing, catching and abiding by the stepping rule.

To maximise D2E programme adoption, the current implementation strategy aimed to empower and educate coaches in the principles of safe-landing technique training, using the D2E resource. The coaches were then expected to implement the programme with their players while noting any emerging challenges. Although coaches adopted the programme, they were more likely to consider D2E relevant for U13, U15 and less skilled players than the very young or more skilled, senior players. At times, the programme was found to be too difficult and boring for the younger players. In contrast, there was the perception that older players lacked motivation and did not believe they needed to develop a safe-landing technique.

In support of existing research12 13 it seems that incorporating D2E into existing coaching workshops and/or accreditation courses would be the most appropriate way to encourage coaches to implement the programme. This would facilitate the dissemination of critical information about correct landing techniques, motor learning concepts and how to access resources, thereby addressing some of the barriers identified to facilitate the adoption of D2E.

The D2E booklet was considered an important resource to assist coaches to implement the programme, with indications that a website and information kit would further aid implementation. Coaches also felt that specific coach training within existing accreditation schemes would assist programme implementation. This finding reinforces coaches' views that they need to acquire adequate knowledge to maximise their capacity to implement injury prevention strategies.13 Coaches also identified a range of barriers to the implementation of D2E including a lack of skills/not being trained properly in this aspect of coaching. While this finding supports the importance of developing the coach as the interface between efficacy and effectiveness in sports injury prevention, further investigation is required to ascertain the particular aspects of the programme for which coaches lacked skills and understanding. In addition, D2E incorporates three key aspects: guidelines for safe and effective landing; a decreasing feedback schedule to enable players eventually to correct their own technique independently and a set of drills to reinforce these components.28 The programme focuses on the control of single-leg landings that are common in netball and uses a progression of drills to develop the level of control required.28 It would be important for future research to ascertain whether a single component of the programme, or a combination, was more difficult for the coaches to implement with particular types of players.

The coaches identified how they adapted and modified D2E to facilitate implementation in their own specific coaching environment. Strategies included decreasing the number of sets and repetitions for exercises and making the exercises easier for younger players, although this was sometimes difficult for coaches to do. This highlights a problem with the translation of scientific evidence generated from the laboratory into a real-world environment. In the case of D2E, the adaptation and modification by coaches makes it difficult to know if the programme would still be effective if a different set of activities were implemented. A comparison of injury rates, however, between a cohort of players exposed to D2E and a matched control group could shed light on the effect of programme modification.

Player-related factors would also need to be addressed before further implementation of D2E. Player concentration and motivation levels, and their perceived value of injury prevention programmes, are key factors that would need consideration. Although our coaches heavily promoted this safe-landing programme, coaches reported that player perceptions of injury prevention were somewhat negative. Subsequently, the only reported disadvantage of implementing D2E was player boredom. Coaches believed that a wider range of drills and exercises, relevant to the skill/age level of players, would enable coaches to deliver D2E in a more enjoyable and game-like way. In addition, coaches believed that players would be engaging in injury prevention practice without consciously being aware of it. Alternatively, a performance-enhancing benefit has been identified by coaches12 and players5 as a factor that would be likely to enhance the adoption of an injury prevention programme. Future injury prevention intervention research, particularly in netball, should thus consider the context in which the programme is promoted.

Evaluation of the maintenance of an intervention should include an assessment of its sustainability over time, particularly after the cessation of the formal research phase.19 This assessment of D2E maintenance was based on coaches' perceptions 17 weeks post-implementation, allowing coaches time to reflect on and observe the intermediate outcomes of the programme. Most coaches stated that they would implement D2E in the future with players of most ages and skill levels, suggesting that they were willing to maintain programme implementation well into the future. It would be worthwhile to reassess the retention of coaches' knowledge and beliefs of D2E principles with an extended follow-up (eg, into the next season).

A major strength of this study is the theoretical underpinning of the evaluation. The RE–AIM framework19 is a well recognised framework for effectiveness research, and this study is one of the few to address the final stages of the translating research into injury prevention practice framework16 by considering an injury prevention intervention within its intended implementation context. Although this study was restricted to one netball association, and on a relatively small sample of coaches, there is no reason to believe that the issues raised would be very different to those raised by junior coaches elsewhere.

In summary, the effectiveness of D2E has been structured and evaluated using the RE–AIM framework, by examining the perceptions of coaches at 17 weeks post-intervention. The programme reached a large proportion of the coaches and players who were targeted and coaches believed the programme to be effective in improving their players' ability to perform correct landing techniques and improving players' athletic attributes. Barriers towards the adoption and implementation of D2E were identified, as were potential strategies to overcome them including: incorporating the programme into coaching accreditation courses; providing more ideas for training drills; making the exercises and drills less physically demanding and more fun and game-like and developing and disseminating a range of support resources. Fundamentally, this research has enhanced the understanding of translating scientific evidence into practice within a junior sport community.