Written by David Hardy, Volleyball Trainer (learn more about David at the end of this article)

WHAT DOES “ACL” AND “MCL” MEAN?

To better understand these injuries, it’s important to understand what the ACL and MCL actually are.

The Anterior Cruciate Ligament (ACL) and the Medial Collateral Ligament (MCL) are ligaments. We tend to think of ligaments as “the things that connect bones to bones”, and they are, but another way to think about them is that they “support” each joint. A joint being the area where two bones meet, the ACL and MCL are two of several ligaments that support the joint we call the knee.

Now, typically there is a certain degree of “allowed” movement in each joint, which is to say, the amount of natural movement that the joint should experience in a given direction. There is also generally “un-allowed” movement, or movement that shouldn’t happen very much in a given direction.

An example of this allowed vs un-allowed motion would be flexion vs extension of the knee. In knee flexion, we can pull our heel back and touch or almost touch our butt with it, but we know it wouldn’t be good if we bent our knee in the other direction (extension) and touched our toes to our stomach. Our ligaments work to help keep these joint motions in check so that they stay within the allowed ranges as opposed to the un-allowed ranges.

INJURIES IN NON-CONTACT SPORTS (LIKE VOLLEYBALL)

When ACL and MCL injuries happen in a non-contact setting, it’s typically because the joint was forced too far into the un-allowed range and the ligament could not hold up to the stress.

To give an example of this, the ACL works to help prevent “hyperextension” which as I mentioned above, would be the knee bending so that the toes touch the stomach. In a situation where a person lands sloppily on one leg and the knee caves inward into excessive, or “hyper” extension, the ACL would try to prevent or limit that motion. If it couldn’t handle the force, it would tear.

Understanding what ligaments are and what they do, it is important to note that you cannot actually “strengthen” them; they remain the way they exist and have a certain “breaking point”. Once that breaking point is reached, damage occurs. All we can hope to do is keep them from reaching that point.

To decrease the chance of that happening in a non-contact scenario, we need to look toward the muscles. All motion that happens within the body happens as a result of the muscles. The way it works is that the muscles contract, and when they do, they pull on the bones via their attachment through their tendons. When that happens, the bones move around their joints, which are supported by the respective ligaments.

So understanding that motion itself is dictated by muscles, it stands to reason that the halt or slowing of this same motion is also the result of muscles. For motion to stop, it first needs to be slowed, and this is referred to as deceleration. And in most non-contact injury situations, it’s the lack of the body’s (or more specifically, the body’s muscles’) ability to effectively decelerate, that ends up being the cause.

Running, shuffling and landing (after jumping) create motion at a high velocity, and when this motion isn’t properly slowed, the momentum can force joints into an un-allowed range leading to a tear in their ligaments. How then, can we reduce the risk of this happening?

REDUCING ACL AND MCL INJURIES

We can improve the neuromuscular efficiency and strength of the muscles responsible for decelerating the motions required for volleyball. Neuromuscular efficiency (NME) is the ability of the nervous system to properly recruit the correct muscles to produce and reduce the right amount of force at the right time during motion. This can be simplified as “body control”, or the ability to control motion in a safe and efficient manner.

Strength is the amount of force that a muscle can produce. So, neuromuscular efficiency, pertaining to deceleration, can be improved by doing and getting used to motions that require a good amount of proper deceleration. This would be agility training, jump training and focusing on proper landing and running/shuffling mechanics. And of course, you increase strength by properly performing resistance exercises for the muscles you want to strengthen.

As you begin to train and strengthen these muscles, in addition to performing dynamic movements with them, there will eventually be an improvement in neuromuscular efficiency. So which muscles should be the focus when it comes to this kind of training, with the goal of preventing this specific type of injury? Well, to say the muscles that dictate direct motion of the knee is kind of a no brainer, but they aren’t the only muscles that matter. In fact, they might not even be the most important.

The knee is a particularly stable joint that is stuck between two particularly mobile joints, the hip and the ankle. However, in what we call the “kinetic chain”, the motion of one joint has an effect on the other joints in close proximity. If you were to stand up right now and shift or rotate one of your hips, you would likely see and/or feel the corresponding motion happening at the knee of that leg. The same would be true for the ankle. So what, then, happens when excessive, unchecked motion happens at the ankle or the hip and the knee is forced to deal with it?

In some unfortunate cases, it results in an injury of the knee. It makes sense, then, to also pay attention to and train the muscles of the hip and ankle, if our goal is to decrease the likelihood of these particular injuries.

OVERVIEW

To summarize, the ligaments themselves cannot be strengthened and will maintain the same resilience to injury, regardless of what type of training is done. That being said, we can strengthen the muscles that work to reduce the amount of stress the ligaments would be put under. We can also improve how efficiently these muscles do their job. In an effort to decrease the likelihood of damage to the ligaments of the knee, the muscles directly responsible for creating and controlling motion at the knee should be prioritized.

However, due to the way motion at the hips and ankles also affects the knees, the muscles dictating the motion of these joints should also receive attention. Of course, no amount of training will 100% guarantee that an injury will not occur, but proper training following these principles can drastically reduce the chances. This is especially true regarding injuries of the non-contact variety.

DAVID HARDY

NASM-CPT, PES, CAFS

David Hardy has been a volleyball trainer in Northwest Indiana since 2014. A staff member of Trademark Performance Corporation, David trains youth volleyball players of all ages and can often be found on weekends watching his athletes play in local tournaments. Follow David on Instagram and Facebook, or call (219) 319-0110 to book a training session with him today!