Back of Knee Pain from Running with Wil Seto

Mark: Hi, it's Mark Bossert. I'm here with Wil Seto of Insync Physio in Vancouver, one of Vancouver's favourite physiotherapists and physiotherapist offices. And we're talking bodies. Today we're gonna talk about back of knee pain from running. How you doing Wil? 

Wil: I'm doing good, thanks. How about you?

Mark: Good. So, sometimes you get that back of the knee pain when I used to run. I don't run anymore. I gave up. But what's that from? What can cause that? 

Wil: Yeah. So one of the most common things and some of our physios have been treating a few runners that just ran the marathon here. And basically it's an overuse injury of a particular muscle in the back of the knee.

And so the muscle, it's called the popliteus. So just wanted to give you the name there. And basically the muscle becomes overused because it's very multifactorial. So it's not just like one thing and you look at the loading of training for something like a marathon. And you look at all the loading that happens with the training and so the popliteus muscle has a couple main functions. 

It's main function is, it flexes the knee and it helps with unlocking the knee joint. And preventing the femur, the top of the thigh bone basically dislocating over like the bottom leg. And then the secondary function of this muscle is that it acts to basically hold in place like stability, like it stabilizes the joint on a more static level. 

So how you usually injure it, like I said with an overuse, like you can also injure it traumatically but we're gonna talk about more of that overuse, kind of gradual onset. And like I said, there's multifactorial things going on and if you have over rotation of your lower leg and then you add all that load in repetition, then as you look at over time, then that can really be a big factor for that.

Mark: So why does over-training or how do you even stop this? What's the cause of this?

Wil: That's a great question. So quite often it would be someone that presented with like some previous injury or a history of an injury before. So in these specific individuals that have come in, you know two of them have actually had like reconstructive ligament repair. Reconstruction of the ACL, which is a major ligament of the knee. And so obviously when you have a surgical procedure like that, you really change the mechanics of your whole knee and your leg.

And then they rehabbed and it's been like, I don't know, maybe even like two or three years since the surgery, but their mechanics is still a little bit off. And then now they're like, Oh yeah, I wanna run a marathon now. This is my first marathon. I can, you know, test myself.

And so if they're not careful, then you can really have these compensations happen if it's weaker and you have weakness that basically occurs on the one side and you're not fully rehabbed strong enough, and you're not looking at the mechanics of your running.

And so essentially with that forced rotation and then you're getting excessive strain and pull on that popliteus when your foots in contact on the ground, and then your lower leg is essentially fixed. 

Mark: So is that the main cause? Is that someone's had reconstructive surgery or can this happen with other people?

Wil: Yeah, no, it can also happen with other type of injuries or even back pain and back stuff where essentially it's the changes in the mechanics of the leg. And when you have that extra rotation for whatever reason, whether it's like an injury or it happens to be that with something like ACL reconstructive surgery, it's a little more dramatic.

And so what happens there then, you know, you really gotta go through the rehab process to be able to have a proper normalization of the movement in that knee, in terms of mobility, but also the strength and the coordination of all the muscles around there. And so that's the main reason.

Mark: So how do you go about diagnosing it when someone comes in? 

Wil: Yeah. So there's different stages of it and we get runners that come in or even like from running sports like Ultimate, football, soccer and all that stuff, where you get pain over the sort of back outside of the knee. And it can be sometimes even just be painful like standing on it, going upstairs. And the range of motion is usually incomplete, like you're lacking range. And there could be even swelling and people usually have pain in that area. 

Mark: And so does the course of treatment include like, working on their biomechanics so they're not flexing or twisting in the wrong way that their body can't adjust to?

Wil: Yeah, 100%. And it's so crucial to be able to correct the maladaptive movement pattern. Because if we just settled down the muscle overuse aspect of it, then it doesn't necessarily fix the cause of it and how it all started. And then the other thing to really note too, like you know, when people come in with this, they're usually more concerned about like bigger things going on, and it's valid, right?

Because there could be other stuff going on that's legit. Cause it is in that area where, oh, maybe there's like a hamstring strain or like a meniscal injury, which is basically the cushiony part of the knee. Or ligament injury or something like that. And so people come in usually you know, being quite surprised when we assess their knee and one of our physios says, Well actually, you know, your ligaments are fine and you actually have an overuse in this muscle. And they never even heard of the muscle before, it's like, oh, popliteus. It's like, you know, the first time you've even heard of that word or that name of that muscle. So sort of an awareness to that too. 

Mark: What's the recovery time look like? 

Wil: Recovery time can be really good depending on how aggravated and like how bad it is, I guess. So you can have it where it's like super inflamed, then you gotta let it settle down first. So there's gonna be like a good few days where if it's swollen. So if you have pain just standing and walking and climbing stairs, then it's probably a little bit angry at you.

So you gotta let it settle down a little bit. And so that period you know, in terms of like, ok doesn't hurt with walking anymore. Then you look at, well then what's the gradual progression get back to like now doing a little bit more? And so typical timeframe is you know, we usually get runners back depending on how serious it is, but within like a couple weeks.

But the key is really unloading. So with these runners, they're doing like pretty heavy mileage per week. Or even if you're just recreationally running, like as you decrease the mileage, now you're just doing three and ones for five sets, that's significantly less than you know, 50 kilometres per week kind of thing. 

So decreasing the load is key too, in the first stage. And typically it takes about four to six weeks to fully recover to really work out that biomechanics of everything and making sure that the movement patterns are good in your hip, and also what's going on in the back, and how your core strength is activating. So that way you're not over rotating when you're making contact on the ground, when you're heel striking. And pushing through and you're not getting into that extreme range and aggravating it again. 

Mark: If you're having some back of the knee pain. The guys to see in Vancouver are Insync Physio. You can book online at, or you can call the Vancouver office, (604) 566-9716. They also have a North Burnaby office (604) 298-4878. You can book either place online at Thanks so much for watching and listening. We appreciate it. Thanks Wil. 

Wil: Thanks, Mark.