In the past we discussed that Anterior Cruciate Ligament (ACL) injuries are on the rise, noting some staggering statistics on its prevalence. We also mentioned some functions of the ACL, like being a key player when slowing down from a run or sprint by helping prevent forward movement of the shin out from under the femur. The ACL is commonly injured when there is frontal shin movement forces with a fixed foot, excessive internal rotation forces on the shin when the foot is fixed or hyperextension forces on the knee when the shin is fixed. In the recent ACL post we also posed some questions about why ACL injuries are on the rise, noting an important one being loss of muscular integrity leading to improper motion and stability.
When we workout we create micro tears in muscle fibers. As a result, the body increases inflammation to start the healing process. With the stress of working out, the resulting inflammation can alter the communication between the nervous system and muscle system. This ultimately leads muscles to not be able to contract properly.
Have you ever completed a workout and tried to come back too soon to do it again and noticed decreases in performance? When working out in this state, with muscles are not optimally recovered, your body is not able to produce forces like normal. This is because they have not fully healed, and many athletes operate in this state since it is common to do different types of movement and exercise when in an under recovered state. An example is for an athlete to lift legs one day and practice the following day. After a workout, inflammation accumulates to start the healing process. This reduces contractile properties of muscles that act as stabilizers to joints.
Since muscles are the first line of stabilization in the body, if they are weak and unable to control motion, ligaments will take the load. This is why over-training can cause increased injury rates. When in an over-trained state, the nervous system is operating in a more sympathetic state, which is also termed the “fight or flight” branch of the nervous system.
With new technology we are beginning to understand this relationship between the nervous system, inflammation and injury. For instance, we are currently seeing many professional teams start to monitor the state of the nervous system of their players to determine if they are in an under recovered state. What many people do not understand is that when the nervous system is in a state of sympathetic overload, the result is higher levels of systemic inflammation. Since inflammation decreases muscle contractile efficiency, when the body is inflamed we can see higher levels of injury because sympathetic hyperactivity leads to greater inflammation which decreases muscle contraction. Decreased muscle contraction decreases joint stability and leads to greater forces on knee ligaments such as ACLs and greater potential for injury.
However, what if there was a way to determine the integrity of the muscular system to ensure an athlete or client poses necessary stability for movement BEFORE injury?