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Reducing the incidence of ACL injuries in AFLW.

The Australia Football League women’s competition (AFLW) was the start of what has been a fantastic past 3 years for female sport in Australia. Young girls who are growing up watching/playing or considering playing football now have someone to look up to at the highest level. However, this expansion seems to be coming at a cost, and that cost is a dramatic rise in the incidence of anterior cruciate ligament (ACL) injures.


“AFLW began in 2017, and had 8 players tearing their ACL. The following year, 2018 saw 9 players tearing their ACL.” Australian Associated Press, 2018


Presently in the media, AFLW is a point of discussion, mainly around the increasing incidence of players injuring their ACL. The inaugural season of AFLW began with 8 teams, followed by 2 new teams this year in 2019 and 4 more are scheduled to join in 2020, increasing the competition to 14 teams and approximately 490 players. With 4 rounds remaining of the 7 game season, there has already been 5 players sustain an ACL injury and if the data is any predictor, could see the competition increase the ACL count by approximately 10% two years in a row. Raising the question, why is the incidence increasing?


Talking Points –


· Lack of experience

· Questions with Physiotherapist Tim Rowland

· Landing Mechanics

· 2 key risk factors

· Recipe for disaster

· Methods of remedy


Lack of experience


One thing that stands out clearly is the lack of experience a lot of these girls have at a high intensity/professional level, partly due to the competition only being in its third season, but also with a lot of players having played less than 30 games of football in their careers.


AFLW is still in the very developmental stages and a growing percentage of players in the league have transferred from other sports (often also state/national level) due to the athleticism that they possess or potential opportunities that weren’t available in their chosen sport. The most common sports that players transfer from are basketball and netball, as the general skills transfer over well, in terms of being able to catch the ball, position your body in a contest, move swiftly across the playing surface and change direction quickly.


Seeing debutants grace the field is almost a weekly occurrence in AFLW, which sounds terrific and it is, but in what other sport do you see newly drafted players, who may have played the sport for <12 months walk straight in and play in their first season?


In the men’s competition each club may draft 4-6, 18 year olds per year that often have played since AusKick (5-6 years of age), for only 1-3 on average to debut at the top level the following season due to either physical or skill capabilities.


Questions with Physiotherapist – Tim Rowland (Athlete's Authority)


I spoke with Tim Rowland, who holds degrees in both Physiotherapy and High Performance Sport and works as a Strength & Conditioning coach and Return to Sport specialist.


Q. How big of a significance do you believe adequate physical preparation in the form of periodised training, exposure to high intensity running/change of direction & strength training is in reducing the risk of ACL injuries to female footballers?


A. While some ACL injuries, especially contact ACL injuries, are very difficult to prevent (e.g. if non-modifiable internal risk factors are present), I believe the large majority (~80%) of ACL injuries could be prevented by proper training and load management. For me, proper training for ACL injury prevention looks like normal training! - single leg strength work in the gym, jump/land mechanics, change of direction mechanics, reactive agility drills/SSGs at training.


I posed the question to Tim that perhaps a tough decision needs to be made, on the potential of athletes being restricted in terms of game/training load in order to try and reduce the increasing rate of injuries being sustained.


Q. What do you believe is the best way to monitor/build these players to aid their development into strong and robust athletes?


A. I think data needs to be gathered on the training history of each of the girls and groups need to be created that reflect the training history (acute:chronic workload). From this, you can then increase the lower training age girl’s volumes over a period of a few months.” If you have GPS look to increase their total km and total high speed meters around 10% each week (can be quicker if starting off at a low total volume e.g. <8km per week). In terms of monitoring ideally take RPEs for each session and also wellness scores (measuring fatigue, soreness, sleep, nutrition) at least once a week. To see how they are handling the training. And encouraging open lines of communication between the athlete and the S+C/Physio to report any issues. Same rule of building up volume also applies to gym. If they are new to gym, then two full body sessions a week is fine. This can be built to 3-4 sessions a week over a period of several months.


Q. If you had to pick one single area to focus on, that you believe would greatly reduce the incidence of ACL injuries, what would it be and how would you implement it?


A. I believe the ability to effectively absorb force is the most critical element of ACL injury prevention. Because ultimately a non-contact ACL injury occurs due to the inability of the knee to properly absorb force when landing or cutting. To develop this quality, I work through a jump/land progression with my athletes.


Starting from: -tall to shorts (double and single leg) -altitude landings (double and single leg; different planes - forwards, lateral, rotational; with/without cognitive distraction e.g. ball catch) -plyometrics - extensive (e.g. pogos) to intensive (e.g. triple hop, single leg depth jump); and in different planes (vertical, horizontal, lateral); progressing to combined planes e.g. forward double leg jump > single leg lateral bound.




I created this graph to represent Tim’s answer to my second question. As you can see, by gradually increasing the training load of the partial and little training history groups towards that of significant training history, we can individually progress athletes overtime at a rate that allows them to develop the necessary physical qualities required by the sport. Obviously this is a best case scenario, and as discussed above, is not what happens currently.


Landing Mechanics


Nearly three quarters of all ACL injuries are non contact injuries.1

Biomechanical risk factors for ACL injury include the maintenance of dynamic stability around the knee through neuromuscular control and the magnitude and rate of impact forces generated during landing 2. The list of studies that go on to support facts such as those listed above are endless, yet the incidence seems to be ever increasing for ACL injuries.


In a game that requires rapid deceleration, unpredicted change of direction and the ability to absorb forces far greater than your own bodyweight, it is disappointing to see the continual injuries occur when the method to reduce the problem is quite simple.

If we look at two risk factors of non contact ACL injuries in females being, high peak-impact forces and poor lower extremity neuromuscular control, and break these two risks down, we can start to develop an effective process to reducing the incidence rate.




Below I have extended on the two sections of the previous table, which lists the method that may be best suited to evoke change, potentially how long may be spent in each area and what the benefit will be from each phase.





Shown below is Lachlan Wilmot’s plyometric continuum that he developed to progress from novice to advanced levels of plyometric exercises.



A similar approach can be used to develop a training strategy to build solid foundations for injury prevention. Below is a simple example of a progression template I created to begin introducing key aspects of landing mechanics into your athlete’s program.




Methods of Remedy


Proprioception and Neuromuscular Control programs:


There is mounting evidence behind the practice of participating in programs that specifically focus on increasing an athlete’s ability to be aware of their position in space relative to what surrounds them and the ability to control their body through motion, significantly decreases the likelihood of injury. Which when put into simple terms makes sense, because before you learn how to write, by gripping the pen or pencil properly, learning to control your fingers and hand simultaneously and developing the fine motor skills needed to write neatly, you're a terrible writer. So why shouldn't athletes take the same care for their own preservation and success when it comes to sport?



The table shows a 2-year study on the implementation of a neuromuscular and proprioceptive training intervention before any athletic activity. It consisted of education, stretching, strengthening, plyometrics, and sports-specific agility drills designed to replace the traditional warm-up 3. Highlighted in bold, are the results from both years, which show a significant decrease in ACL injury following the implementation.




This is an infographic I created to demonstrate the data a bit more clearly the significance of this study. The most important part of this infographic is the pie chart in the top right corner which addresses the total number of ACL tears throughout the duration of the 2 years. Despite the difference in group sizes, in relation to total number of members per group, the test group sustained approximately >5x less less ACL tears.


Here is the program that was completed by the test group.




Increasing knee flexion during landing:


To partner with the implementation of neuromuscular & proprioception interventions, placing a focus on the angle of knee flexion at moment of contact with the ground along with the range of motion the knee goes through during landing, has been shown to greatly decrease peak ground reaction force/total force placed through the knee.


A simple way to experience the effect this simple fix has is to try this example out at home. From a standing start, jump up in the air about 10cm off the ground and land with straight legs and take note of how it feels throughout your entire body. You probably noticed how abrupt your body came to a halt and felt the force of the ground ripple up your body. Now try the same exercise, but focus on landing with softly bent legs (roughly 15-20o) and take note of how it feels. If done correctly, you should have felt no abrupt halt, and it should have felt relatively soft. This is what can be achieved through focusing on increasing the flexion of the knee during landing.



The table above shows the variance in 4 aspects of measurement in relation to the relevance of knee flexion angles during landing from 39 health recreational athletes. The results were gathered by completing a volleyball jump task in an instrumented gait laboratory. Pre-modification jumps were performed first without any modification to their technique, followed by post-modification jumps where they were given oral instructions to land softly and increase their knee flexion during landing 4.


This table clearly shows a large decrease in vertical ground reaction force which has been shown to be a risk factor for ACL injury.


Conclusion


Whilst it would be great if we could prevent 100% of injuries, unfortunately this is not the case. What we can do however is reduce as many injuries as possible, through sufficient preparation and an increase of physical readiness.


This article only scratches the surface of possible solutions but brings to the forefront perhaps 2 of the key areas we should be focusing on in proprioception/neuromuscular control and knee flexion during landing.


The AFLW is set to expand again next season, which will bring more women into the professional ranks. We need to be doing our best to ensure these women are on the field, showing their best so that future generations can be inspired to follow in their footsteps.


I hope that you’ve enjoyed reading, if you have an questions, feel free to get in contact with me directly.


References


1. Boden BP, Dean GS, Feagin JA Jr, Garrett WE Jr Orthopedics. 2000 Jun; 23(6):573-8.


2. FERRETTI, A., P. PAPANDREA, F. CONTENDUCA, AND P.P. MAR- IANI. Knee ligament injuries in volleyball players. Am. J. Sports Med. 20:203–207. 1992.


3. Bert R. Mandelbaum, MD, Holly J. Silvers, MPT, Diane S. Watanabe, MA, ATC, John F. Knarr, PT, ATC, Stephen D. Thomas, MPT, Letha Y. Griffin, MD, Donald T. Kirkendall, PhD, William Garrett, Jr, MD, PhD. Effectiveness of a Neuromuscular and Proprioceptive Training Program in Preventing Anterior Cruciate Ligament Injuries in Female Athletes: 2-Year Follow-up


4. Julien Favre, PhD, Caitlin Clancy, MS†, Ariel V. Dowling, PhD, Thomas P. Andriacchi, PhD. Modification of Knee Flexion Angle Has Patient-Specific Effects on Anterior Cruciate Ligament Injury Risk Factors During Jump Landing 2016



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Hello. My name is Adriano Arguedas Soley, welcome to my online strength and conditioning journal.

Here, you can find articles written by myself and other coaches, learning resources and podcast episodes where I've had the pleasure of interviewing some of the leaders in our field. 

 

Through this online platform I share with you some of the things that have helped and continue to help me in my development as a strength and conditioning coach.

If you'd like to get in touch, please do not hesitate to email strengthcoachjournal@gmail.com

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© 2019 by Adriano Arguedas Soley 

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