The ACL is a band of dense connective tissue between the femur and the tibia. The anteromedial bundle and posterolateral bundle both make up the ACL, however depending on the angle at the knee the force that is then transferred through these bundles may alter. An uninjured and functioning ACL would limit and control excessive ranges of motion from the tibia. (Petersen and Zantop, 2007) The ACL attachments are at the articulations of the knee joint. However when the knee is fully extended there is no impingement due to the broad insertion on the tibia (both bundle insertions are anterior to the intercondylar tibial eminence). The origin of the bundles are on the posteromedial side of the lateral femoral condyle. (Siegel, Vandenakker – Albanese, and Seigel, 2012).
ACL injuries are one of the most common injuries in rugby and team sports especially Rugby union. To prevent the non contact ACL injury, it is vital that there is an understanding of the mechanisms of the injury (Yu and Garret, 2007). Multiple studies confirmed that non contact ACL injuries in rugby union were common during weight bearing movements with the knee in shallow flexion and the foot in contact with the floor such as decelerations, landing, change of directions and side stepping (Shimokochi and Shultz, 2008). These findings were also supported by Montgomery et al (2016).
Here are a few prevention strategies:
- Practicing repeated sprints and sudden stops at multiple speeds and distances to mimic those the athlete would do during a game in a controlled manner.
- Side stepping and cutting practices at different speeds and angles. Having other team mates to chase or block allowing for the athletes to challenge each other, and be more specific to the lack of predictability they may face on the field.
- Landing practices also play an important part. Drop jumps and other exercises that may have a more plyometric element (E.g drop jump with immediate vertical jump, single sided exercises or leg hops) may help with this (Haff and Triplett, 2016).
- In addition to using these exercises to visually screening the landing (identifying internal/external rotation and values knee), they can be used to practice and allow the athlete to consciously correct over time (Mok and Leow, 2016). The lack of co-contraction of the hamstrings has being linked in multiple studies to ACL injuries. Therefore focus on increasing strength and rate of muscular activation through compound exercises (for strength), eccentric loading and more explosive plyometrics or olympic lift variations, looking at the angle of knee and hip flexion (for power).
- With all this being said the practices can be introduced prior to in- season to allow for familiarisation and also to any athlete that has any been identified as being at risk of injury (Posthumus,Durandt, and Hons, 2009).
These suggestions are not exhaustive as there are more exercises that could also be included. It is important to remember if this is for yourself or an athlete you coach, base these choices on the individual (training history, position specific and movement patterns on and off the field etc to identify the risk of injury). Start with just a few of these exercises at a time to allow for adaptation if they haven’t been done for a while or at all.
Finally looking at research on recovery methods and reducing the likely hood of fatigue should not be overlooked. (Tavares, Smith, and Driller, 2017).
Another thing that shouldn’t be overlooked in injury prevention of the ACL, is the training experience or number of years an injured athlete has been playing in rugby (this could be a potential risk factor). Along side this mental state should also be considered as most decisions that are made during games/ tournaments are often down to an emotional response.