Tendon Compression Explained

: On today's episode, tendon compression explained. Welcome to the podcast helping you overcome your proximal hamstring tendinopathy. This podcast is designed to help you understand this condition, learn the most effective evidence-based treatments and... bust the widespread misconceptions. My name is Brody Sharp. I'm an online physiotherapist, recreational athlete, creator of the Run Smarter series and a chronic proximal hamstring tendinopathy battler. Whether you are an athlete or not, this podcast will educate and empower you in taking the right steps to overcome this horrible condition. So let's give you the right knowledge along with practical takeaways in today's lesson. Thank you for joining me on another episode. I have been meaning to do this episode for a while, but, um, well, pretty much because on either injury chats, which you are jumping on, which is lovely. Uh, or the clients that I have treating PhD. Um, like I say, I have a lot of them and essentially because of this podcast, uh, a lot of you are sort of gravitating towards me, which I love. Um, thank you so much. And. I'm getting a couple of times, um, a few responses of yes, I hear you talk about compression a lot, but I still don't fully understand it and put into the back of my mind. Okay. I'm hearing this more often than not. So let's put an episode together, but you know, it's hard. It's such a, I guess one little question or one little topic to try and fit it out into an entire podcast episode is probably the reason why I've. haven't, I haven't really necessarily created an episode. I'm like, Oh, is there enough here? Is there enough content to produce an episode? But nonetheless, I'm going against that idea just so I can have a resource to point people to when the next person says, you know, I understand you talk about compression a lot, but I still can't grasp it. I still can't fully comprehend. And You might need to listen to this episode a couple of times because I get it. It's an audio format and you do need like, it took me a while to understand tendon compression when I was graduating and they'll talk about tendon rehab and compression and like, okay, what does that fully mean? It just took a few examples for me to grasp. And those few examples took like. tendon models or took like, you know, the skeleton models where you can sort of see how things move and what the tendons are doing and what the, where the attachment points are. And once I, once I understood it, it was quite simple, like the analogy or the examples are quite simple, but it just needs to be explained in a, in a way that people can understand. And I understand you as a PhD rehab or just trying to understand more about it. is going to be tough with an audio format and your, your background of anatomy and tendon function isn't to the degree of like university, but nonetheless, I have tried my best to lay it out in the best way that I can in an audio format to try and help explain tendon compression. And I guess if you're not too sure of why we're talking about tendon compression, um, maybe have a listen to a few earlier episodes. You'll notice that, say the papers, when I talk about research papers on PHT rehab, early stages, they'll mention, you know, train the or strengthen the hamstring out of compression. And then stages two, three, four is start to tolerate deeper levels of tendon compression or tolerate higher levels of compression. So there's a lot of reason and premise to kind of understand what And it has to, the only way we can start is by talking about the anatomy, talking about the structures, particularly the hamstring tendon, where it attaches and grasp that first before I move on to something a little bit more complex, which is talking about the compression itself. So. You have a couple of hamstring tendons, but let's just simplify it and talk about one main origin that attaches. So obviously, you know where your hamstring is as it travels up your hamstring up the back of your thigh. It the tendon itself attaches to the sitting bone. So the hamstring, well, first of all, tendons are they act as anchor points. So every muscle will along its path when it gets to the end of the muscle will become tendon and that tendon attaches itself onto the bone. It's that creates like a pulley that it's required to anchor itself onto the bone to create movement. We try we move the bones of our skeleton to create movement and the hamstring itself attaches onto the sitting bone but it wraps underneath the sitting bone first and attaches itself behind the sitting bone. So if you are sitting, if you can imagine sitting on a firm surface, you feel your bones, you feel your sitting bones making contact with the chair or making contact with that surface. Your tendon passes in between your sitting bone and that surface of the chair and wraps itself behind to the other side of the sitting bone. That's why sitting can be quite annoying. and quite aggravating for some people who can't tolerate compression because we're essentially squashing the tendon between the bone and between the hard surface, the hard sitting surface. And so when we say compression, when sitting is concerned, it literally means squashing the tendons, compression. But during movement and exercise is where it gets a little bit tricky. If you don't have a physical surface squashing the tendon, say for like a deadlift or a squat when we say that's high loads of compression, what does that actually mean? The sitting analogy or visualizing sitting is a bit easier, but now we're moving on to the movement and exercise. And the best way I can describe it is by visualizing, you know, one of those gym pulleys, you know, the cable that wraps around the pulley wheel that has a little groove that the cable kind of wraps around. and then you can attach it to say, it's got a strap and you can hold onto the strap and do like a bicep curl or do some leg exercises. If you can visualize that pulley, that will definitely help this because I'm gonna talk about it a lot. So you have the cable that wraps around the wheel and the wheel has a little groove in it that allows the cable to sit in it. And the cable wraps around that wheel in certain... directions. It might be like a 90 degree direction. It might be all the way like almost close to 180 sort of wrap around. And let's use the example of an exercise. So the cable itself attaches to a weighted rack. So the rack which you can assign different weights, you can move the pin to pick up different weights, and then that cable moves itself down, let's just say that wheel is close to the floor, and then the cable goes down to that wheel, wraps around the wheel and comes back up, and we do say a bicep curl. So that cable attaches to a strap, we hold onto that strap and we do a bicep curl. As we do that bicep curl, the cable pulls that weight, wraps around the wheel and pulls the weight up as we apply force. If you're not familiar, let me just Google, machine weight pulley. If you just do that, look up images, you can probably see what I'm talking about. You can see some topless people doing bicep curls, you can see some topless guys doing tricep dips and the pulley kind of system. Importantly, you grasp that. If you're not grasping it, then go to Google, look at Google images, and then we can move forward. Let's say, oh well, let's say we're doing that bicep curl. There are two main forces applied to the cable itself, because this cable is gonna represent our muscle and our tendon. So it's important that we understand this. One is tension. So the cable itself is getting pulled by the weight at one side. and my biceps at the other side. So it's getting stretched, but because it doesn't have any stretch qualities, it doesn't actually lengthen, but the tension is being applied to that cable. But the other force that's being applied to that cable is compression. The compression is around that wheel. So it's being, as a lot of load is being applied in tension, as it wraps around the wheel, it's getting squashed into that wheel. It's getting pressed into that wheel. If you try and take that cable and you try and pull it away from the wheel, if it's under tension, it's not going to release it. You're not going to be able to lift it or pull it away just because it's getting squashed into that wheel. Hope that makes sense. And this is more or less happening to the sitting bone, just in different types of compression. And these different types of compression we're going to delve into because different angles will allow for different contact on the pulley and I'll explain in a second. This podcast episode is sponsored by the Run Smarter Physiotherapy Clinic, which is my own physio clinic where I help treat a wide range of PHT sufferers, both locally in person and all over the world with online physiotherapy packages. In the years I've been self-employed as a physio, close to 70% of my entire caseload has been helping people with proximal hamstring tendinopathy, which is why I decided to launch this podcast. So if you're building upon your own rehab knowledge through the podcast, but still require tailored assistance, I'd love to be on your rehab team. Whether you are a runner or not, head to runsmarter.online to see your available options for working together. If you're still unsure if physiotherapy is right for you, or if you need a rehab second opinion, you can always schedule a free 20 minute injury chat with me. Find the free injury chat button on my website or in the podcast show notes. to be taken to my online calendar to book in a time. So different angles of the pulley. Let's just use the above example of that bicep curl. That cable that runs from the weight rack, which is going to be quite high, let's just say it's about five feet off the ground. Then it travels straight down, wraps around that wheel, comes back up and attaches to your hand, to your bicep curl. If you're focusing on that example, the cable is making a lot of contact with that wheel. It's wrapping all the way around close to like a 180 degree movement before it comes back up. And so when you apply force, there's a lot of contact of that cable on that wheel. And therefore there's a lot of compression that's being applied to that cable. On the other hand, if we had If we were doing say a hamstring curl where we are facing the cable and the pulley Cable is the strap is now attached to our ankle Which is like if we're sitting and facing that pulley the foot is at the floor and then we apply say a hamstring curl It's almost like a 90 degree Direction that the cables heading in it's going straight down to the floor. It's wrapping around that wheel And then it's almost following the line of the floor as we pull that cable doing a hamstring curl. Now, if we focus on that particular angle, it's almost moving in like a 90 degree direction and there's less compression, there's less contact time of that cable on that pulley wheel. And so we can count that as kind of less compression. It's under it's undergoing the same amount of tension as you would say with a bicep curl if it's the same weight if we are curling the same as much as we bicep but the level of compression is less. I've got one last kind of example here which we're going to move the wheel position so let's just say that the wheel is the cable is attached to the weight rack let's just say the weight rack is at the height of our head. And the wheel. is at the height of say our shoulders and we are lying on the floor, looking up at that cable and doing, and we're pulling that cable towards us. Let's say it's like a row or something. You can imagine that cable just continues to travel straight down and almost bypass the wheel. It can still make contact with the wheel, but you're hardly, it's hardly making any contact because the direction of the cable is straight down. And if you try to take that cable and pinch that cable and move it away from the wheel, you could probably do that even if it's under tension because the level of compression is extremely less. So that push that the cable, the compression of that cable into the wheel is a lot less. So this is more or less what's going on with different hamstring exercises. You have exercises where you're undergoing more compression, more wrapping of that tendon around that sitting bone. but then less compression where that tendon isn't just really squashing into that bone at the same degree. Yes, it can be under the same tension. We can work that hamstring really hard, but it just be under less or more compression. So as I said before, we know that the hamstring attaches behind the sitting bone. So certain exercises can lead to the tendon wrapping around the bone a little bit more or less. The examples that I can use is say a hamstring curl, where what we call like a prone hamstring curl. Most people would know this as, let's use a thera-band for an example. You're lying on the floor, on your stomach, everything out straight, and then you get a band and you attach it to your ankle, and then you bring that ankle towards your glutes in a hamstring curl fashion. Because your hips are straight, that tendon doesn't have to wrap around that sitting bone as much as other exercises. So that example is kind of like the third position that I described with our row, where the cable is moving straight down to the floor and hardly making contact with that pulley wheel. That would be an exercise out of compression or with less compression. If we say, take another example and do a sitting hamstring curl. So, Not really focusing directly on the compression onto the seat, but just visualize a hamstring curl where you're sitting and the hips are bent at 90 degrees. So when the hips are bent at 90 degrees, the tendon has to wrap around the sitting bone longer. And then you still apply tension to the hamstring by doing a seated hamstring curl. That means that as you apply tension to the hamstring, that tension is being applied. So force number one, but then force number two, compression. It's wrapping around that sitting bone at kind of like a 90 degree position. So it's kind of like that second position of the pulley that we described before, where it moves at like a 90 degree. And yes, compression is being applied. More compression than that exes, the previous example. but we can even compress it more by doing things like really deep deadlifts or really deep lunges, these sorts of things, especially deadlifts because I guess with a squat, you are definitely going into really deep levels of compression, but you're not activating the hamstring in a primary fashion. You're mainly using your glutes and your quads when you do a squat. So yes, it is getting compressed around the sitting bone because you're moving really deep into that position, but the tension isn't necessarily being applied because we need tension to generate high levels of compression that cable needs to be pulled on for it to have compression on that wheel. So a deadlift is a good example because you can go through large ranges of movement with a deadlift and that primarily uses your hamstrings. So when your hamstring activates, that's tension. and that really wraps around that sitting bone because you're going into a really large range of hip movement, hip flexion. And so you've got this interesting combination of tension and compression and large ranges of compression. And like I said before, you might remember from past episodes, the goal of early rehab is to, well, I guess if you can't tolerate large amounts of compression, if you try to do a really easy deadlift, and it flares you up, then maybe you're not ready for that level of compression. The idea in rehab is to try and find what level of compression you can tolerate, but then it's important that you build up to tolerate high levels compression. Rehab progresses, you build up the tendon's capacity to tolerate higher forces of compression. Why? Because it builds resiliency and you need compression for function. You need to compress the tendon to bend over, to pick up a laundry basket, to pick up your kids, to tolerate sitting because if you can't tolerate any sort of compression and then you sit and the tendon gets squashed, it's gonna get sore. So pretty much for function and building resiliency in your rehab, we need to sort of find what level of compression you can tolerate. A physical therapist or a... PT or a health professional can help understand what variety of exercises have low levels of compression, medium levels of compression, high levels of compression, and find where you are on that kind of spectrum and then build up from there. That's one of the main ideas of rehab or the main goals of rehab. So you can build that up and you can do that. Because it's very, very important. I've had people do bridges and to stay with bridges for several months without the idea to progress to tolerate higher levels of compression. And it's only once they start tolerating higher levels of compression, introducing high levels of compression that their rehab, um, makes it turns a corner. So hope this at least gave you a grasp. Like I said, you might need to listen to this again. You might need to Google what those sort of pulleys are. Cause once you can grasp the concept, it makes a lot of sentence. a big game changer for understanding your rehab and why you're doing certain things. And hopefully, my hope is that it encourages you to sort of progress your exercises, to go beyond bridges and prone hamstring curls and start encouraging yourself to do some of these exercises, these hamstring exercises into more levels of hip flexion. So I managed to talk about tendon compression for 20 minutes. I hope that It made sense. I hope maybe if you listen to this a second or third time around the light just switches on and you finally get and grasp the idea I have just, well, at the time of recording just half an hour ago, post on social media around the Facebook groups, some question answers for next episode. So if you do have any questions, feel free to reach out on social media. And yeah, we're doing a Q and a episode next time. Good luck with your rehab this week with your PhD. If you have any questions, like I said, I've got the injury chat available in the show notes of every podcast episode, and we'll catch you next time. Thanks once again for listening and taking control of your rehab. If you are a runner and love learning through the podcast format, then go ahead and check out the Run Smarter podcast, hosted by me. I'll include the link along with all the other links mentioned today in the show notes. So open up your device, click on the show description, and all the links will be there waiting for you. Congratulations on paving your way forward towards an empowering, pain-free future, and remember... Knowledge is power.