Photo: Michael Willson Photography
The anterior cruciate ligament, or ACL, is one of the most dreaded yet most frequently injured ligaments in the sporting arena, particularly common in agility based sports such as netball, basketball and football. A diagnosis of an ACL rupture can mean 9-12 months on the side-lines, something any athlete at any level would be keen to avoid.
We’re going to look at how and why this ligament is so commonly injured and give you some management and more importantly prevention tips to implement into your own training.
Mechanism of Injury
The ACL’s role in simplistic terms is to prevent the tibia (shin bone) from moving anteriorly (forward) away from the femur (thigh bone), however it also has a role in rotational control of the knee joint.
With this being the case the ACL is in its most vulnerable position when the knee is flexed from 0-30 degrees and in an internally rotated position, as seen in our picture above;
There have been multiple studies to show that maximum strain on the ACL occurs when an anterior force is applied to the tibia. These same studies also show that this strain increases when coupled with an internal rotation or valgus force (pressure forcing the knee towards the midline of the body). This is important to understand as it will help form the basis of our strengthening and prevention training programs.
Unfortunately, most ACL ruptures need to be repaired through surgical intervention, especially in the case of the sporting population. This carries with it a lengthy rehabilitation and manual therapy (Osteopathy!) program, with studies showing that adherence to a strong, clinical rehabilitation program will significantly reduce the chance of re-injury.
However, the best-case scenario is to prevent the injury altogether!
Below are our tips on how to Prevent injury in the first place:
- Increase glute strength
Strong glutes will help prevent the pelvis and knee dropping towards the mid-line in single leg stance positions. There are a million different ways to develop glute strength; my favourite (and most specific) is the walking lunge with medicine ball rotation (a bit of a mouthful). It will address glute, quadriceps and core control as well as involving an important rotational component through the knee.
- Master a single leg balance:
This will start to work on proprioception and balance but in a static position, to begin with. Start off by simply standing on one leg, then build to closing your eyes for up to one minute, you can then add sport specific exercises such as catching a ball while balancing, then a single leg hop, land and catching etc.
- Learn how to land
Perhaps the most important exercise in the prevention program! Learning and practicing how to land is essential to develop proprioception and motor patterning in this position. Basically, the body will become more familiar with this motion and less likely to land in an awkward position.
The best way to train this is with depth jumps, both double and single leg.
A really nice and challenging progression on this is the partner push landing, as shown here..
If these are too challenging, then take a step back to the single leg balance and build up to it.
- Increase hip and ankle mobility
If landing and proprioception is not the most important factor in prevention of ACL injuries, then mobility at the hip and ankle joints has to be. The vast majority (especially non-contact) of knee injuries, and we are not just talking ACL here, can be traced back to either mobility or control issues at the hip or ankle joints.
I like to think of the knee as a conduit joint, it is always stuck in between the ankle and hip and as such can only do as much or as little as they allow. If we look at these three joints working as a team they all need to contribute evenly to our general lower limb motion, as soon as one (or two) is restricted the others have to increase their work load, which can eventually lead to injury. Looking at it like this makes us realise that maybe those “unlucky”, “random” non-contact injuries may be a lot more preventable than we think.
Below are two of my favourite mobility exercises
It is important to make sure that any exercises you are doing are being done correctly, otherwise you can cause more damage than good without realising.
If you are ever unsure about what you are doing our Osteopaths and Personal Trainers can work together, with you, to create a full rehab or sports injury prevention programme tailored to your needs.