Latest Trends in Neuromuscular Training to Prevent Anterior Cruciate Ligament Injury: A Literature Review

PURPOSE: Anterior cruciate ligament (ACL) injuries are the most common in sports and have doubled in the past 20 years. This study aimed to analyze the latest trends and changes in training programs for ACL injury prevention.METHODS: In this study, literature was searched using academic search sites, such as ‘PubMed’, ‘Google Scholar’, and ‘Wiley Online Library’. The literature published between 2015 and 2021 was used.RESULTS: Eleven papers were selected based on the literature selection criteria. Five warm-up exercise papers and six ACL injury prevention training program papers emphasized neuromuscular training.CONCLUSIONS: The ACL injury prevention program can be applied in warm-up exercises and training programs. It consists of an exercise form that includes multidimensional components such as plyometrics, muscle strength, balance, and agility. The key to the ACL injury prevention program is to reflect multidimensional components in neuromuscular training and to obtain a significant effect, and it is recommended to participate in regular training for 12-18 sessions and at least 6 months. In addition, it is suggested to utilize the ACL injury prevention program presented in this study until an individual study for ACL injury prevention by sports type is conducted.

Implementing ACL Injury Prevention in Daily Sports Practice—It’s Not Just the Program: Let’s Build Together, Involve the Context, and Improve the Content

Although the benefits of current anterior cruciate ligament (ACL) injury prevention programmes have been demonstrated in efficacy studies, they, unfortunately, have had limited public health impact to date. For example, the incidence of ACL injuries continues to rise in adolescent athletes. Raising awareness and educating coaches and athletes is not enough to facilitate the widespread, sustained use of these programmes in the real-world setting. Considering the profound burden of ACL injuries, it is necessary to continue to improve the current ACL injury prevention programmes through co-creation. First, the uptake of the programmes should be optimized by a better appreciation and understanding of the individual, socio-cultural and environmental context (i.e., community). Second, the content of the programmes should be optimized to better reflect the demands of the sport by creating more ownership and increasing motivation (incorporating challenging, sport-specific and fun elements) with the end-users. In addition, implicit motor learning, random practice and differential learning are concepts that should be integrated when practising to obtain the most optimal results when learning or finetuning skills.

COACH EDUCATION IMPROVES ADHERENCE TO ACL INJURY PREVENTION PROGRAMS: A CLUSTER-RANDOMIZED CONTROLLED TRIAL

Background: ACL injury prevention programs have demonstrated limited impact on population health, due in part to poor adherence to expert recommendations by sports coaches. Neuromuscular training (NMT) serves as a protective factor against ACL injury and serves as a key component of many ACL injury prevention programs. The objective of this study was to determine the effect of an educational workshop for sports coaches on adherence to neuromuscular training (NMT) implementation recommendations. Methods: In a cluster-randomized controlled trial, 22 teams in 8 high schools were randomized to either the intervention or control group. The intervention schools included 12 teams (5 female), and the control schools included 10 teams (4 female). The sports included basketball, volleyball, track and field, baseball, softball, and lacrosse. Coaches in the intervention group participated in a 60-minute educational workshop designed to teach coaches how to effectively implement a NMT program as a warm-up prior to team practice sessions and games. The schools in the control arm received print materials on recommended NMT exercises. Adherence to NMT implementation recommendation by sports coaches was the primary outcome. Eight data collectors, who were blinded to the teams’ assignment, were trained to observe each team’s practice or game 2-3 times a week. At each session, they completed a study questionnaire to identify the exercises completed by athletes during the team’s warm-up. They then recorded whether the coach 1) delivered exercise instructions, and 2) provided corrective cues. Generalized estimating equations (GEE) were used to account for potential correlations among teams at the same school. Results: A total of 399 practices or games were observed over 2 seasons. A greater proportion of coaches in the intervention group provided cues to correct improper technique compared to coaches in the control group [difference=0.04 (95% CI: 0.01, 0.07, p=0.006]. In addition, more coaches in the intervention group completed a full NMT program [OR=4.62 (1.22, 17.50), p=0.02]. There was a similar proportion of coaches in the intervention and control groups who provided exercise instructions [difference=0.01 (95% CI: -0.02, 0.04), p<0.44]. Conclusions: Coach education can improve adherence to NMT implementation recommendations and the delivery of corrective cues during NMT sessions, which are both critical to reducing the risk of ACL injury. All coaches should receive in-person training that highlights the salience of NMT and provides the knowledge and skills required to effectively implement NMT sessions with young athletes.

Poor Motor Coordination Elicits Altered Lower Limb Biomechanics in Young Football (Soccer) Players: Implications for Injury Prevention through Wearable Sensors

Motor coordination and lower limb biomechanics are crucial aspects of anterior cruciate ligament (ACL) injury prevention strategies in football. These two aspects have never been assessed together in real scenarios in the young population. The present study aimed to investigate the influence of motor coordination on lower limb biomechanics in young footballers during an on-the-pitch training. Eighteen juvenile football players (10 y ± 2 m) were enrolled. Each player performed a training drill with sport-specific movements (vertical jump, agility ladders, change of direction) and the Harre circuit test (HCT) to evaluate players’ motor coordination. Wearable inertial sensors (MTw Awinda, Xsens) were used to assess lower limb joint angles and accelerations. Based on the results of the HCT, players were divided into poorly coordinated (PC) and well-coordinated (WC) on the basis of the literature benchmark. The PC group showed a stiffer hip biomechanics strategy (up to 40% lower flexion angle, ES = 2.0) and higher internal-external hip rotation and knee valgus (p < 0.05). Significant biomechanical limb asymmetries were found only in the PC group for the knee joint (31–39% difference between dominant and non-dominant limb, ES 1.6–2.3). Poor motor coordination elicited altered hip and knee biomechanics during sport-specific dynamic movements. The monitoring of motor coordination and on-field biomechanics might enhance the targeted trainings for ACL injury prevention.