Physics...Physiology...Physical Therapy

Core is a movement, not a place

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‘Core’ is such a buzzword in the health and fitness world. But what muscles comprise it and what does it actually mean? We can all think of ‘core’ exercises (e.g. planks, crunches, etc), and we’re core-rect about that (sorry, couldn’t help it!), but we’re selling ourselves short if we are satisfied that these will get us the results we want. Let me also be clear, if the results you want are simply to look good, then planks and crunches will go a long way, but if you want a functionally strong core, then we’ve got to dig deeper.

Since this is a running blog, we’ll keep it in the context of running. Someone please stop me if this gets too geeky.

Think of your core as the place where movement initiates from and pivots. This can vary slightly from person to person. As you lift your knee to take your first step, a series of muscles need to fire to make it happen, this should start around the lower abdominal region, then the hip flexors, quads, tibialis anterior, etc. From there, every time your foot hits the ground, there is a force that travels up your leg (think Newton’s law: for every force there’s an equal and opposite force), as a result of your body weight striking the ground. As that force travels up your leg, your leg muscles should contribute to the shock absorption (think bucket brigade). When that force hits your hip and lower torso area, it should be able to be quickly and readily absorbed, which loads those muscles and allows them to push-off for the next stride. At this point, your upper body should be helping to leverage your lower half in order to make it easy for the next push-off.

So essentially, the forces of your body should pivot around your belly button when you are running. Quite often, this is not the case. Quite often, due to weakness in our lower core, that force has to travel further up our torso before enough other muscles are involved to effectively put the brakes on and send the force back toward the ground. When this is the case, what it can often look like is excessive arm swing, straining of the neck and shoulders, forward trunk lean, or a head that moves too much. Here are a few examples.

What these all have in common, is that their arms and upper bodies are tattling on their cores. Essentially, they have to use their arms and upper bodies differently to help absorb and leverage the forces that should be taken care of in the lower core. This amounts to decreased efficiency and performance and higher susceptibility to pain.

So, let’s pick on traditional core exercises again for a moment. What’s typically lacking is the vertical component for how the muscles need to work. This often means that key muscles (gluts, pelvic floor) don’t get strengthened in a way that actually translates to the demands of running. Can’t you just hear your six-pack muscles saying ‘thank you! can I get some help from below?!’ Here’s an example of a progression that engages your core in a way that translates to running.

There are several ways to modify this also. By using a 5-10# weighted object, that will increase the load, and make you work much harder. By taking bigger strides and going deeper into the lunge, that will increase the workout also. This can also be done as a run form drill, by holding in your arms in any of the 6 positions, based on what tendency you may be trying to overcome. What you should be feeling is the your hips and lower core region is working much harder to keep stability, since you are effectively taking your upper body out of the equation, or biasing it toward a direction of weakness.

Hopefully that all makes sense. Perhaps a more lengthy video with verbal explanations and demonstrations would be helpful. Please let me know if you would like to see this explained in more detail. Let me know how this goes for you!

Knee pain in a jumper

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This is Jeremiah, he is a stud high jumper and runner who has had right anterior knee pain, which is his jumping leg. Our discussion today is in the context of jumping, but the biomechanical principals certainly carry over to running as well. We didn’t take any footage of him running, but this video of a single leg squat tells us plenty!

There’s a lot that can we can draw from watching him do a single leg squat. As you can imagine, every time he jumps off his right leg, he has to load that leg in a squatting movement. The biggest muscle groups that are responsible for propelling upward to jump are the gluts, quads, and calf. So the question that helps us is, how do these muscles know when they have been loaded enough to propel him skyward? There are a few factors that go into the answer. In order to engage the foot and calf, the big toe and medial forefoot have to be driven into the ground to their end-range. In the video, you can see his forefoot pronate heavily, which causes his knee to fall inward rather dramatically. In order to push off, he needs to have a rigid forefoot to propel with, which happens at the end-range of forefoot pronation. Only when his forefoot reaches the end-range of pronation, do the bigger muscles further up the chain (calves, quads, gluts) get the signal that it’s time to push off.

I realize that became a little geeky with the biomechanics, but stick with me. What it boils down to for his knee, which is where the pain has been, is that when it comes time to push off, his knee is at an awkward angle, which means that the quads are pulling on the tendon (front of knee cap) from a direction that is dysfunctional and weaker. This causes increased stress on the tendon and certainly affects his ability to perform.

So, what to do about it. What is tough to discern from the video, is that structurally he has forefoot varus, which means that when his ankle and heel are in a neutral position, his big toe is off the ground. This is a common thing, and most people with this type of foot appear to be flat-footed. One of the first things we did is put a little pad under the base of the big toe. This will hopefully be a temporary measure to cause the forefoot to load more quickly and keep the knee in a happier position. We also did this exercise to encourage the whole leg to stay in more proper alignment. The pull of the thera-band forces his gluts to fire more quickly, as well as strengthens the medial quad (VMO), and helps teach the foot and knee to stay in better alignment.

As you can see, his foot has to struggle to keep proper alignment. It certainly will take some work to build a better habit with this. Here is another simple exercise to strengthen a foot that demonstrates these types of patterns.

Again, with constant practice to build strength and consistency, this will help keep his knee in better alignment and get rid of the knee pain. Keep up the good work Jeremiah!

These principles also carry over to running. If you think this may be an issue for you, watch yourself do a single leg squat in a mirror, if your knee is dipping inward excessively, you might respond well to these exercises as well. Let me know how it goes.

Forefoot pain and hip weakness

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This is Jasmine. She is a superstar runner who is beginning her track season. Some of the issues she has dealt with include forefoot pain and calf stiffness. Her low back has also been sore at times. She is not limited with running, but these are frequent annoyances. Another quirk is that toward the end of a race or tough workout, her head tends to move a lot, sort of like a bobble-head. We don’t have any footage of that sadly, but you can catch a glimpse of it when close up! Here is video of her at the beginning of a run.

From behind, the most obvious parts are the increased loading time in the hips both sides and slowness to push-off through the feet. From the sideview, she has a forward trunk lean. What these indicate is weakness in her hips and core, especially in the context of loading in the sagittal plane (forward/backward). Essentially, every time her foot hits the ground, her hip and lower core region should be able to quickly absorb the force of the ground traveling up and transfer that to an efficient push-off. Instead, it takes extra effort to absorb that load, so she’s forced to lean forward and leverage her head and neck to pick up the slack. Ideally, her head and upper body should be fairly quiet and relaxed because the work is mostly picked up by the lower half.

So, what to do about it. We have already been working on the flexibility of her hips and calves, mostly working on posterior and anterior hip flexibility, which videos of others doing these can be found in previous posts of similar runners, as well as calf stretches with twists thrown in. Again, these can be shown in recent posts. So these videos focus on the running form aspect.

First, another assessment video. The instruction given was simply to stay on her toes. This can be a great way to discern how strong the forefeet are. Often, if the form worsens when running on the toes, that’s a dead giveaway that lack of foot strength is part of the equation. Indeed that’s what we see with Jasmine.

Here is a simple drill to emphasize quickness with the loading phase and power during push-off phase. I’ve heard these most commonly referred to as ‘power skips.’

Next, to develop proper core control in the sagittal plane, she ran with the most convenient object with a little weight to it, a purse!

What this accomplishes is that it forces her to stay more upright and stable through her upper body. This can be done with any object that weighs a few pounds, a backpack, a rock, or a small weight. From the side, her upper body certainly stays more upright, which is a great sign! From behind, her head and shoulders stay more stable, also a great sign!

After these drills, here is what her form looked like.

From the side, she certainly looks more upright. From behind, her feet and hips look quicker and more efficient. So these are good indicators that the drills will be helpful for developing better patterns for stability and efficiency and should translate to better performance. Great work Jasmine!

Hip and Achilles pain, where do we start?

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This week’s spotlight is on Victoria. She is a rockstar collegiate runner who has had bilateral hip pain and achilles pain. Her pain has made it difficult to train and compete over the last year. Originally, she began experiencing hip pain after performing lateral lunges. The achilles pain had a progressive onset several months later. Most of these videos are taken several weeks into treatment, so she has already made progress. Here is footage of her running.

I apologize for the video not being very close-up, but we can make it work! The biggest things that jump out to me are the hard landings/slow push-off of both feet, as well as her high and tensed arm swing on both sides. There is a little excessive hip motion side to side also.

Upon more thorough assessment, we found deficits in her hips’ external rotation, as well as limited inversion of her rearfoot(heel bone) both right and left. How do these findings translate to running form? With hip motion, as your leg swings through it is primarily going through flexion, but on a more subtle level it is also externally rotating. As the foot hits the ground, there needs to be enough margin in the flexibility to allow the muscles to load further to accept body weight onto that leg. If you’ve used up the flexion/external rotation too quickly, than the glut muscles are not able to properly accept the load, which means something further up the chain must do that. Enter the high and tensed arm swing. While running, our arms serve mostly as a way to counterbalance our lower extremities and load the core from above to allow for overall improved efficiency. This also opens up another discussion on the core that we’ll get into at a later time. In brief, think of your core as a pivot point for the body. With running, that pivot point should be relatively close to your pelvis and lower abdominal area. For Victoria, her pivot point was much higher, closer to her upper back, which is why her arms have to work so hard to give the counterbalance her lower body needs to move forward. She also has struggled with neck, shoulder, and upper back tightness for some time.

Her feet also need addressing, as the inability of her heels to invert, translates to a poor transition from loading of the foot to pushing off. In order to push off well, we need to be able to pry our heel off the ground, while the foot and calf are in a loaded position (dorsiflexed). Hopefully that makes sense, I think a more thorough video on this specific topic may be forthcoming! Anyway, here is what we did to improve the foot mechanics. Notice that she is in a traditional calf stretch position, but the focus of the exercise is to rotate the lower leg to unplant the heel, without actually lifting the heel up. In the video, I’m assisting the movement, but it can be done without help.

We also did a stretch for the posterior hip. It’s most helpful to do it in two stages, first the rotation of the hips, which is shown very briefly at the beginning, and secondly the forward trunk lean.

After these active stretches and movement exercises. We took to the pavement to work on form drills. Rather than focus on feet and lower extremity stuff, we monkeyed with her arm position to see how this affected the rest of her.

These types of drills are helpful for developing better core control while running. As discussed above, the core should be a pivot point between the upper and lower bodies. Where exactly that pivot point is can make a huge difference when it comes to running more or less efficiently, as well as with or without pain. For Victoria, her pivot point was way too high. This isn’t something that can just be consciously corrected, so a way to monkey with this is to put her arms in an extreme position. This forces her body to establish a difference pivot point, because the arms are no longer able to counterbalance as they had been. Ultimately this forces her hips to work more efficiently because they can’t pass the buck higher up the chain as they were previously.

Comparing the videos with her hands to the right and left respectively, it’s helpful to note that her hips looked more efficient with her hands to the right. This can reveal Right-Left imbalances as well, though we focused on both sides equally today.

After these drills, here is another video of her running. Again, all the running videos were taken after we had already improved hip and foot motion, so the change isn’t as dramatic, but still very important.

Notice her arms are more relaxed and there is less hip side to side motion. With continued focus on more efficiency with her transition from load to push-off, and working on core stability/mechanics as mentioned above, she will continue to make gains over the coming weeks. Great job Victoria!

Hamstrings bend my knee right?

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The hamstrings are a misunderstood group of muscles. When most people think about hamstring health, the first things that come to mind are usually stretching by touching your toes, standing or seated, or strengthening by seated hamstring curls on a weight machine. Do these stretches/exercises target the hamstrings? Absolutely. Do they teach the hamstrings how they are supposed to behave in functional movements? Hardly.

So this begs the question: what do your hamstrings do and how do we properly train them? The answer: it depends. It depends on what you do. This will look different for a runner compared to a farmer, or a soccer player compared to someone sitting in a desk all day. For the purposes of this post, we’ll keep it in the context of running. Quick anatomy lesson: the hamstrings are a group of three muscles that originate from the ischial tuberosity (sit bone) and extend past the knee, two out of the three on the inside of the knee, the other attaches to the head of the fibula on the outside of the knee.

There are three primary phases for each leg with running: 1) swing phase, 2) loading phase, and 3) push-off phase. The hamstrings have different functions during each phase and it’s important to understand what’s supposed to be happening at each. Also, most of the discussion will focus on the sagittal plane of movement (forward/backward), as this is the most obvious direction to observe. There are movements and forces in the transverse plane (rotational), and frontal plane (side to side) that we’ll touch on, but focusing on the sagittal plane will help keep details a little cleaner.

Swing phase: This is the ‘open chain’ portion of the cycle where the foot is off the ground swinging forward. During this phase the knee should bend as the hip flexes. The hamstring is not responsible for this knee bend, but rather the hip flexors driving the femur forward and momentum of the lower leg created by the push-off. The hamstrings during this phase are partially responsible for slowing down hip flexion as the swing phase ends, but are relatively quiet at the knee.

Loading phase: This is where the fun begins. As the foot touches the ground and body weight is loaded onto the planted foot, the hamstrings become more awake. At the knee, the hamstrings are mainly responsible for keeping the knee stable, not allowing terminal extension too quickly, nor allowing the knee to further flex. (The soleus is mainly responsible for controlling the knee during loading phase, but the hamstrings also assist with this.) At the hip the hamstrings eccentrically control anterior pelvic tilting, which translates to preventing trunk/pelvic flexion and ultimately keeping your upper body upright. The tricky part about this phase is that the hamstrings are responsible for both the knee and hip. As long as the knee and hip are behaving, than all is good, but if there is dysfunction in any of the adjacent joints or muscles, than this can cause a brief, unhealthy, tug-of-war which can quickly translate to a strain or pull.

Push-off phase: At the transition from loading to push-off, the hamstrings act like a catapult helping to propel the hips forward over the fixed lower leg. The hamstrings assist with extending the knee at this point to allow for full push-off. Then the leg is back into swing phase.

Again, when considering hamstring health, it’s most effective to train them in a way that translates most directly to what they need to do for the specific activity. The majority of the hamstrings’ contribution to running occurs with the foot planted on the ground. Because of this, the most effective hamstring exercises are done with the foot on the ground or planted on something, and the upper body mimicking the movements that occur during running. Here are a few examples.

First, a stretch for the hamstrings with rotational reaches to target different parts of the muscles.

Next, a strengthening progression, essentially a single leg deadlift, then hip rotations to strengthen the hip rotators.

Lastly, a variation of the single leg deadlift with theraband around the knee to challenge control in keeping the knee out of early terminal knee extension.

Give them a try or pass these on to someone who may appreciate better hamstring strength or flexibility. Let me know how you do with them!