Why are ACL injuries so common?

by Evan Christodoulou 0

Image: Graeme Furlong

As the 2017 season kicks off again for the NPL, we already begin to hear the horrible news about players (young and old) ‘rupturing’ their ACL (anterior cruciate ligament) so early in the season. This article is designed to educate you about the anatomy of the ACL, the risk factors associated with tears, the prevention mechanisms, and other contributing factors as to why it is so common these days.

Keep in mind youth players should also be aware of this as ACL ruptures are usually a result of incorrect conditioning throughout youth years.

Anatomy/Risk Factors

When we mention the ACL, we need to consider the main structures in the knee that play an important role in soccer, which work in unison.

There are four main ligaments in the knee that stabilise our knee joint to keep our tibia (shin) and femur (thigh) compact to allow smooth movements in different planes.

Within your knee capsule you have the four main ligaments, which I will mention only two based on this topic: the ACL and PCL.

The letter ‘A’ stands for anterior (front), as it runs from the back lateral side of your femur (thigh bone) and connects to the anterior medial (front) of your shin bone, whereas the PCL, ‘P’ being posterior, runs in the opposite direction from the front of the shin to back of the femur, so if you could see this from the side of your knee, the inside would look similar to the letter ‘X’.

The ACL prevents the shin from moving forward compared to the thigh, similar to the way you can grind the bottom row of your teeth forward while the top remains still. The ACL is about 3cm long that attaches into each bone; think of it as rope rather than elastic.

Our ACL is under the most tension when we are near extension (straightened knee) with an inwards rotation of the knee, and now you can visualise your foot being in front of you when running about to plant on the floor and you either suddenly twist or get tackled (force from the outside coming inwards), causing the ACL to tear. There are many reasons why it can tear. To name a few, it can be from:

  • Poor running technique – Where your foot plants too far in front of the body, increasing the ground reaction force loading the ACL too much over time, making it weaker. Gait training is very important and unfortunately something that is overlooked.
  • Internally rotated hips – Where your thigh bones angle inwards, mainly due to weak glutes (minimus and medius), which increases the load on your ACL during every stride/kick/pass/turn/shot.
  • Muscular weakness/posture imbalances – Muscles also increase the stability of the knee joint to keep these forces minimal. Our quadriceps, hamstrings, gluteals, and calf muscles are our anchor points (secondary stabilisers) that must all be well activated and strong to keep the knee joint compact and tight. If they are not, load is increased in an uneven matter which increases negative forces and tension in the ACL, decreases good posture/alignment, and can change our movement patterns.

The difficult thing to understand is that the average footballer will not identify the deficiencies plus many more, nor know how to correct them. Your body will try to manage it as best as it can, making it ‘hidden’ until it becomes under stress to breaking point, which can take months or years. Strengthening ligaments and tendons is vital for injury prevention, so don’t be fooled by athletically built players or ripped bodies – this doesn’t mean anything if your ligaments are loose, weak, and not providing accurate information to the brain.

Other factors increasing our risk of tears

There are also external factors in today’s game that have an impact on ACL ruptures that were not as evident going back 20+ years, to which previous footballing generations would say ‘we never used to cop those injuries’.

Let me explain some reasons as to why it is more common these days:

  • Game speed/intensity has increased over the years – We need to be stronger, faster, more agile, cover more ground and be more technical, which has a direct impact on the demands placed on the body, as it will be under more stress and required to do more for a longer period of time.
  • Longer seasons/more cups/ more work – We are required to play more games in a season, additional to more competitions in the background, i.e cups (FFA), which decreases our rest and recovery. This over time takes its toll on the body, not allowing recovery of musculature, increases mental fatigue and lethargic bodies, which leads to poor decision making and movement. We also work longer hours, sleep less, eat nutritionally poor foods, which also reduces recovery, muscle/ligament repair and optimal functioning of the body.
  • Grass vs turf – Not only are our pitches harder, meaning our joints undertake massive amounts of forces and tension that we label as ‘soreness’ and ‘stiffness’, but we have also been introduced to artificial turf, which generally has a rigid foundation and rubber surface that does not allow proper ‘give’ and ‘softness’ on our bodies structures, making it more difficult to turn, twist, and cushion our movements which again increase joint loads.

So what do we need to do now?

Regardless whether we talk about player management at an A-league level or your local leagues such as NPL or lower (obviously there are vast differences in funding, player commitment, and access to allied health professionals) but the big factor missing in all tears is the education surrounding how to prevent serious injuries such as ACL ruptures from occurring, and if we remain ignorant we will see no changes in the occurrence of serious injuries.

The human body is an amazing structure that requires preparation/training to prevent injuries from occurring.

The ACL, for example, is at its highest risk of rupturing when the foot plants in front of the body at near full extension with internal rotation of the knee (e.g leg out in front with a sudden twist or tackle forcing the knee inwards). This means it doesn’t have to be a bad tackle, but as simple as an awkward turn or landing where the body cannot react enough to correct the error in movement.

So, in terms of strength and conditioning, normal exercises such as squats, although they will strengthen these secondary structures of stability such as the quads, calves, lower back and hamstrings, we need to focus on strengthening the ligaments and tendons, which are the primary stabilisers, as well as the muscles that maintain correct alignment such as the glute minimus and medius.

Proprioceptive training is also ignored (I’m sure not a lot of people reading this will know), which is vital for injury prevention. NPL has already begun, and most teams have suffered an ACL injury in either pre-season or the first few rounds of the season.

Summing up

Money is no excuse for clubs not investing in correct player management. You don’t need to employ an exercise physiologist, sports chiro, physiotherapist 52 weeks a year to achieve great results.

An exercise specialist can prescribe programs on a monthly basis to manage/monitor performance and injury prevention (a much cheaper option).

We can undertake seminars/presentations to educate coaches and teams about physiology, activation/prehab methods, recovery to assist with education/knowledge (even cheaper again).

A prerequisite should be for clubs to form a partnership/relationship with a clinic, specialist, or allied health professional to refer players too when seeking injury prevention/recovery or even advice, so the platform is at least there (this is free) for players/coaches to access. If we continue to take shortcuts and find excuses to not look after players from youth to senior levels, don’t expect season-ending injuries to stop anytime soon.

Just because you attend the gym on your own with your generic program or self-made program thinking you are doing the right things for your body, you will be in for a vast reality check. Ask someone who has been through an ACL rehab process and thought that they were functionally sound (it’s a long, frustrating, and slow process). Like any degree, if you want a good service, you have to seek it from people who specialise in that field.

For more information/inquiries email evan@walkingtallep.com or visit our Facebook page ‘Walking Tall Exercise Physiology’.