Ben Serpell – ACL Injury

Ben Serpell is currently the Athletic performance coach at the ACT Brumbies Rugby Union club. He works closely with the team physios, coaches and medical department to make sure each athlete is training optimally. Bens previous work includes weights & rehab for Port Adelaide AFL club and before that was in England working in Rugby Union where he completed a Bachelor of Occupational therapy.ben-serpell

Ben’s research at ANU is looking at ACL injury and the role of pre-tension and pre-activation – the dynamic muscle stiffness and the relation to ACL injury. This stops the ligaments being stressed during ground reaction forces. The method of training for this is plyometric training in order to increase performance and potentially protect against injury. Ben recently presented his thoughts and experience on ACL injury as part of the Master of High Performance Sport degree. His presentation is summarized below along with some reflection from myself.

Key Points:

Ben regularly sees common mechanisms of ACL injury. A high proportion come from snow sports as the foot is locked or fixed in ski boots for example. Roughly 70% of injuries occur from non-contact mechanisms for field and court sports. Over last 4 years though he has seen 6 out of 9 ACL’s from contact so research can give one indication but it may be something completely out of our control. Typically there will be a low flexion angle, rotation about the knee and a valgus movement. You will see an almost straight legged foot plant from outside the centre of mass of the body. With contact injuries you will see the same things at the knee joint in the kinematics of the injury. This is the 2nd most severe injury in sport after hamstring injury in regards to lost game time and cost to rehab, surgery and physio.

A couple of non-contact movements leading to injury were then described by Ben. A Power cut – An example of such a movement was explained wherein a left change of direction is made off the right leg. A Speed cut – is where the left change of direction comes off the left leg. This comes back to improving cutting techniques and knee flexion angle.  By being better able to absorb load and then reproduce that force during dynamic cutting movements will reduce injury risk in his opinion.clyde-rathbone

Ben went on to list other known contributors to ACL injury: females, a fixed foot position, skill level and the genetics of the knee. In a roundabout way this justifies much of his interest in this injury as even though these contributors have been known for many years injury occurrence has not improved. Therefore you would think it is worth more research to further understand the injury and to decrease the risk of injury.

How does Ben identify risks within his athletes? Firstly, looking for a weak hip or core that is causing the foot to be planted out wide from the body. Then poor hip control, especially when fatigued, you can unnecessarily load up the glutes, then the hamstrings and then the hips so you can no longer properly unload the knee. The athlete needs to get to the point where they can plant their foot whilst having synchronisiation of your shoulders and hips to control the foot plant.Cheetahs v Brumbies

What can you do once risks are identified? The training of leg stiffness through plyometric exercises is a good start. Begin training pre-tension through running on the sand or uneven surfaces. Hip control is important as the legs will go all over the place if poor control in hips – try practicing sticking landings to improve this. Foot plant needs to be right below your centre of mass – if you can teach someone to run well in a straight line first then you can translate that into sideways movements by using the shoulders to change direction. Instruct the athlete to concentrate on dropping the shoulder to steer the rest of the kinetic chain and the rest of the body will naturally follow.

Ben stressed that it is important to remember during the rehab process that no two injuries are the same.  Therefore, we must customise the program for each individual.  Also, sports are different too – For example, Rugby league players will be back quicker as they spend more time strengthening the lower extremity in normal circumstances compared to AFL (usually out to 12 months) or soccer but there is no general rule of thumb.  Also the type of surgery undertaken will also govern the type of rehab. For example, at the 6-10 week mark the new graft is at the most vulnerable state and you really don’t want to stress it too much with high impact forces during this period. Preferably Ben would only introduce gentle strengthening work during this time of rehab.

After Full rehab is there anything that he looks for? Hip, hamstring and core weakness in particular – especially if a hamstring graft has been used for the surgery there will be weakness in the hamstring and at a higher risk of a tear. It is a good idea to test hamstring strength during this period along with integrating plenty of gliding movements that progressively stretch the hamstrings in the first 6 weeks. Continue working hamstring strength and function throughout to minimise injury in this area and by 12 weeks you ideally want full extension of the knee.nord

At the return to play stage is there anything to look out for? Yes, the hamstrings again (stretching / strength) and also consider the adductors as they can become sore and overworked by compensating for a lack of hamstring strength. ITB lengthening and stretching to reduce fat pad impingement whilst limiting asymmetry around all these areas. This is important during the first 12 months as once you run asymmetrically you increase the risk of injury recurrence in all areas.

Any advice for those getting into High Performance Sport? Don’t expect $$$ but keep knocking on doors and opportunities will come. Ask plenty of questions as you can learn from anyone you meet. Be prepared to move and be away from home as often the best opportunities aren’t always in your own backyard. If you really want to do it you will get a chance so just grab it and run with it by trying to learn as much as possible. Spend time with different types of coaches that work in the sport to get the whole picture around the sport. Having an attitude where you “Never want to stop learning” creates a great depth of understanding that can transfer across to many other areas of sport. In dealing with injuries and in closing – Understand where you would like the athlete to be by the end of the injury so that you can gauge how far they are – as every injury type will be different.

Application to High Performance Environment:

Ben touched on the effect of diet and how we as practitioners can impact their recovery early in rehab up until 12 week phase. For me, I hadn’t really factored the importance of diet into recovery from surgery as I was concentrated on his implementation of different exercises.  So for Ben to mention this made me consider it rather than just the rehab protocols themselves in returning an athlete from injury or surgery. By effecting diet you can aid in creating stiffness through the ligament during that period along with the necessary rehabilitation exercises as previously mentioned.diet_plan-1

Ben also commented on the best graft type is in his opinion – The Hamstring or patella tendon? This would be a common question asked of you in a high performance environment so having experience with each methodology along with solid research to back up your recommendations would be important. The patella has risk of patella tendonopathy down the track whilst the hamstring graft has its drawbacks also. If it is on the same limb as the knee you are at risk of injuring your hamstring with a particularly increased risk in this in first 12 months. Ben sited no preference but either way you should be stronger in hamstring strength and function post injury compared to before the injury regardless of what graft is chosen.

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