Direction of movement impacts speed!
One of the tests that we perform is called a hop plant (in the video here). During this test, the athlete hops in four directions (forward, backwards, lateral and medial). During the course of the test, they are instructed to keep the contralateral leg off the ground so stability has to solely come from the limb being tested. Since tracking this on over 14,000 athletes, one trend we have seen is that there are much higher numbers (magnitude of valgus and speed of valgus) associated with the medial hop. If you dissect this motion and what is going on, it makes a lot of sense.
In this motion the athlete is standing on one leg. They must push off on the lateral aspect of their foot with enough explosive power to get their center of mass moving medially. At landing, they must resist the medial momentum at the knee and stabilize the knee and prevent from going into a valgus position. At the same time, they must also activate the core and hip to counteract the medial momentum of the center of mass (trunk) from continuing to move medially. This is obviously a very challenging motion but also one that is very relevant to sports.
What we know is that athletes who's motion exceeds 20 degrees of valgus at speeds higher than 220 degrees/sec tend to have more chronic lower kinetic chain issues (meaning non-contact ankle injuries, hamstring strains, etc). We also know that if we can improve these numbers, the frequency of these non-contact chronic chain issues goes down.
As an example, if you look at the athlete here. She is performing the task and successfully, but she has a lot of internal rotation, some valgus and her hip is dropping on the left side indicating right sided gluteus medius weakness. If I were to train this athlete and let her continue to do these plyometrics in this fashion, she would get stronger. But the default movement pattern that she would rely on would be this movement pattern. Hence I am training her to a potential injury down the line. If she is unable to perform this task without allowing her knee to go into valgus and her hip dropping, then I need to step this back to a less aggressive exercise until she is strong enough to do this with proper movement.
In other words, we should focus less on the ability to perform the task as the pre-requisite of progressing someone's program and focus more on the fact can they do it with proper movement. As basic as that sounds, this is where we fail all too often. We hope you have found this useful and is something you can take away and implement tomorrow with your training or with the training of your athletes.
Next week, we will continue that discussion on the impact of concussion on lower kinetic chain movement. Stay tuned as I am super excited to share with you. If you enjoy this blog, please share with your colleagues, athletes and training partners and please be sure to follow us on instagrm @ bjjpt_acl_guy and twitter @acl_prevention. Train hard and stay well. #ViPerformAMI #ACLPlayItSafe