TAKING NOTE: Justin Moore on "knees in", internal/external rotation and training on the Just Fly Performance Podcast

Hey there, I’m back today with the second instalment of this series where I share what I have learnt from various podcasts and other free resources in a more short and easy to digest way. I’m going to share what I got out of episode #176 of the Just Fly Performance Podcast with Justin Moore. There was a decent amount which they covered in this episode so if you like what you read here I recommend you go listen to the podcast as well.

Before we get started, as always, I just want to say that these ideas/concepts are not originally mine and rather this is just my interpretation and breaking of what I have learnt from the podcast. If you are interested in the topic I highly recommend you listen to the episode and support them. The link to this podcast is: https://www.just-fly-sports.com/podcast-176-justin-moore/

Now, let’s get into it.

Why does “knees in” occur?

First off, lets talk about why athletes present with their knees coming in on jumping and squat movements.

The practical reason is that this internal rotation at the hip joint is a moment of elastic return for the athlete so that they can jump higher/produce more force. Many of the best jumpers/lifters in the world do it and if this is true, it can be safe to assume that there is something to it.

It is useful to understand mechanically why/how this occurs. To do this, Justin uses Bill Hartmans model which explains movement at the hip. I believe that the squat is the easiest way to illustrate this, and Justin explains it this way in the podcast also. Basically, if you follow the arch of the hip joints and sequentially how the femur will move you will be able to see the following movement. As you descend into the squat, (hip flexion) the femur will externally rotate, as you inhale and expand, resulting in the pelvic floor descending with a relative nutation of the pelvis, this is expansion. This is a lot of actions at once however if you follow it through, it makes sense. I think that it is important to note however, that in this movement, all of these actions occur together. Then, after you reach the bottom of the squat, move back up and move past the sticking point, these will all reverse, mainly (in terms of what we are talking about here), the femur will move into a relative moment of internal rotation and compression of the system will occur here. This is where your knees might knock together.

Also based on the model, in the gait cycle, as you move into toe off, the same thing would happen again in the other direction, relative external rotation as you reach the end of hip extension and then returning to internal rotation as you enter recovery phase of your gait cycle. This is interesting to note because your femur moves through a larger range of motion in gait compared to a squat or jump.

I have made a (somewhat) decent graphic showing this external/internal rotation here:

All of this movement should mean that you can see the pelvis moving straight up and down, with a thorax oriented directly on top of it and with no other relative movement of the pelvis either backwards or “tucking under”. The only movement of the pelvis itself should be intrapelvic and up and down.

The nutation of the pelvis is why this is able to occur. When the nutation of the pelvis occurs (in the down phase), this allows the pelvic floor to descend, and allowing the guts to drop with it. This occurs alongside the diaphragm also descending in a “piston like movement”. When this reverses as we move back up out of the squat/loading of the jump, the movement into relative IR of the femur/adduction assist in the counternutation of the pelvis, ascending the pelvic floor (along with the diaphragm) and essentially will help to “propel” the athlete up and the guts ascend back up.

What we get out of this is that the way the pelvis is structurally and the way it moves at the femur moves into flexion/extension, allows for us to produce more force and move somewhat more fluently.

Essentially, with all of this in mind, if the system self-organises itself to move this way for a number of reasons discussed above, and it makes sense from a mechanical standpoint, then maybe we shouldn’t be trying to completely coach it out of all athletes. However, it’s not all great when it comes to the knees coming in, and that’s why it is important to discuss when it can become a problem.

When can knees in be an issue?

The main issue with knees in, which is why people try to coach athletes out of it, is injury.

The first most obvious way this can increase the occurrence of injury is if the knees are literally knocking into each other. While this doesn’t happen as often in athletes, Justin say’s that he has seen multiple cases of it and this can become an issue.

The second reason that this can become an issue is because of the relative stability at the knee joint due to the lack of degrees of freedom and how the lower leg moves in this presentation of knees in. Because the feet are still on the ground when this is expressed, while the femur is going into internal rotation, the tibia is going into relative external rotation and these to movements occurring together is when issues occur.

If either of these occur too often due to the knees coming in, the main issue is that while the athlete may be able to create more force, they are also more likely to develop chronic pain which may prevent them from training and competing over time.

Pretty much, when an athlete is presenting more extreme cases of this knees knocking together, or if they have a history of knee pain, this might be where we as coaches intervene. Obviously there is context specific factors and everyone is individual however this would be a starting point to identify this. Now that we know this, we can move into how we may address it.

How can we look to address this?

When explaining this, Justin gives an example of a figure skater who he worked with who presented an extreme case where her knees literally knocked together when she jumped. The other side of this however was that she had one of the bast fore jumps compared to anyone she was competing with. This issue resulted in a large amount of pain not allowing her to train as much as required. Pretty much, without telling all of his story, this needed to be addressed.

The way Justin suggests that this can be addressed is by trying to teach the athlete how to adjust their breathing mechanics of expansion/compression. Essentially, some people will either be dominantly compressed or expanded. Based on the requirements of their sport, this can either be beneficial or counterproductive. This goes back to the basic principle which explains why we don’t see people who look like they are going to be able to run a marathon lifting world record weights and vice versa.

In this case, the figure skater had a relatively inhaled skeleton with an exhaled compensation. This means that for her to produce the movements that we spoke about before, she needed to move into more internal rotation of the femur causing this motion which was affecting her negatively.

In order to counteract this, Justin worked on building a greater concentric strategy to allow her pelvic diaphragm to ascend on exhalation more effectively and prevent this knees in movement. He needed to teach her to guts moving up through a propulsive strategy starting from slow to moving fast while maintaining coordinative and respiratory control.

Practically he used box squats and then having her exhaling and propelling off of the box. Her would keep on teaching this as he takes away the box and she increases velocity. He added velocity and intensity in the pogo jumps while cueing her to have an aggressive exhale on her propulsive movements. They also work on her control of hamstrings and glute max so that she can better control the movement of the femur and also the intrapelvic movement occurring in nutation and counternutation.

Through this work to teach her to how to exhale fully, she learns all of these movements that we described earlier without having to internally rotate her femurs so far. This for her worked and she learned how to move better from the axial skeleton and then from the extremities. This reduced her pain and improved her mechanics so that she actually performed better.

In this case, her mechanics have now improved and we have avoided the issues of knees in. While allowing for this propulsive strategy was beneficial, the relative benefits of being pain free and practice more where more important. She still uses a degree of knees in however this is a safer amount which still allows her to propel when jumping.

Why we can’t go too far in the other direction

There is now a building movement that we should “just let the athletes play the sport because there is nothing wrong with the way they self-organise”. Justin says that this could lead to ignoring things that should be worked on such as with this figure skater. It may not be sustainable to just leave things and let people express movements too far in one direction.

We may need to change the constraints, organism, task or environment for a more balanced output which in the long run will be more beneficial.

Conclusion:

So those are the main parts of what I took away from the podcast. You have to appreciate the forces which are put in the body and understand why the body self-organises in a certain way. Once you identify this and any compensatory strategies, you can look if it is an issue and then work to improve by increasing movement options and giving them full respiratory variability.

A couple of these concepts can be difficult to grasp (I’m still trying to fully) and so I recommend that if you are interested then to look into Bill Hartman’s model and obviously this podcast. Again I highly recommend you go to listen to it. There was even more that he spoke about in it which I didn’t touch on because I simply felt that I wouldn’t do it justice with my current level of understanding. This one will definitely be something I give a re-listen to at some point down the line.

For now, I hope you got something out of this, and thanks for reading.