Thigh high rehab: treating anterior thigh injuries with Adam Johnson

In this episode with Adam Johnson we discuss the different biomechanical demands of the anterior thigh muscles in a task such as running or kicking, and how this can result in them needing specific rehabilitation. He also guides us through the muscle groups that should be incorporated into a rehab program for an anterior thigh injury to help prevent re-injury.

Want to learn more about anterior thigh injuries? Adam recently did an awesome Masterclass with us called “Anterior thigh injuries: assessment to rehab” where he goes into further depth on assessment and rehabilitation of anterior thigh injuries.

👉🏻 You can watch his whole class now with our 7-day free trial: physio.network/masterclass-johnson

Adam Johnson is a Physiotherapist with more than 12 years experience of working within elite football clubs. He is currently a First Team Physiotherapist at Everton Football Club within the English Premier League.

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Our host is @James_Armstrong_Physio from Physio Network 

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Transcript

SPEAKER_01 0:00

you need to have strong hip flexors if you're going to be able to run quickly and the theory behind that being that it allows for a kind of really rapid recovery of the leg during swing phase and allows you to have real good high stride frequency so that's something that really stands out for me thinking about it i'd probably think of rectus femoris potentially as more of a good strong knee extensor but actually when we're looking at running there's a lot of research out there to support that actually predominantly is a hip flexor and that's what we need to be thinking about within our rehabilitation of it.

SPEAKER_02 0:45

In this episode, we get an eye-opening insight into anterior thigh injuries with Adam Johnson as we talk through the biomechanical demands of the anterior thigh musculature, how we translate that knowledge into effective rehab, and then finally the criteria we can use to ensure a safe return to play following an anterior thigh injury. Adam Johnson is a physiotherapist with more than 12 years experience working within elite football clubs. He is currently the first team physiotherapist at Everton Football Club within the English Premier League. And away from his day job, Adam has a large interest in research and has had three papers published within peer-reviewed journals on a range of topics such as hypermobility screening, rehabilitation and injury incidence. Now Adam has done a masterclass with the Physio Network on anterior thigh injuries where you'll be able to get a lot more detail looking at the assessment, rehabilitation and return to play of these athletes. So click on the link in the show notes so you can watch Adam's masterclass for free with our seven-day trial. As always I know you'll gain a lot from this episode so enjoy. I'm James Armstrong, and this is Physio Explained. Welcome back to the show, Adam Johnson. How are you? Yeah,

SPEAKER_01 1:55

I'm very good. Thank you. Thanks very much for having me on. Like I say, again, it's an honour to be back on. So thanks very much for having me.

SPEAKER_02 2:02

Brilliant. And today we've got you on for a very, very good reason. We're going to be talking about a topic on anterior thigh injuries, looking at from assessment to rehab. which coincidentally is a masterclass which you've just done for the Physio Network, which is out now. So we're really excited by that. I know the listeners and our members are going to be really interested to go and check that out very quickly, Adam. So thanks for that. And today's topic is going to complement that really, really well. And we're going to be talking about anterior thigh injuries, which I'm sure many of our listeners have come across. And they're not always that easy to treat. So I think this is going to be really helpful. We're going to dive into something that I think is really important. probably quite crucial to know at the beginning. And that's the demands on one of our big anterior thigh muscles, and that's rectus femoris. So talk us through, Adam, some of the demands, the biomechanical demands on that muscle group in running and kicking, for instance. You're absolutely right. They're

SPEAKER_01 2:57

really complex injuries to manage because, as you say, specifically the rectus femoris plays kind of so many different roles with knee extension, hip flexion. And what's really, really interesting when you look at key papers by Gisendum and Hoff in 2007. And they looked at surface EMG analysis and found that there was a twofold increase in rectus femoris activity as running speed increases. So that gives us a good feeling that the quicker you're running, the more these demands are coming in. Now, as we think about our sports and elite sports, that the game's getting quicker, the demands are getting more intense. So you can see why these injuries might becoming more common and more difficult to manage. And they also reported within that study that the separate timing of the rectus femoris activation compared to the vasti muscles, so the rest of the quadricep muscles, and that led them to propose it probably means it plays a different role with the vasti active just before stance phase, therefore trying to stabilize at the knee and resist downward displacement. whereas the rectus femoris kind of kicks in at the beginning of that swing phase. And therefore, it's been the only biarticular muscle in the quadriceps. However, it's a bit different to the vastar they suggest. It probably plays a role as more of a hip flexor than a knee extensor within running, which is something really, really important to consider within our rehab. And that was kind of backed up by a slightly earlier study by Anderson in 1997. And the advantage of this study is to use fine wire electrodes analysis as opposed to surface ENG. So they can actually look at the hip flexors, so iliopsoas. And they demonstrated that psoas and rect fem had very different activation patterns to the other muscles that they studied as they actually had like two distinct activation patterns, whereas a lot of the other muscles only had the one, so say vasti, just before that stance phase. And they found within that rec fem that there was some activation. There was a distinct activation in that kind of early stance phase as it does its essentially knee extensor role. However, it's got this real big, strong activation just as hip flexion kicks in in the swing phase. And again, really, really supports its role as a predominantly hip flexor role with the rectus femoris as opposed to a knee extensor. And again, probably another study to back this up, really recent study actually from Miller in 2022, which looked at actually muscle volume, so slightly different, but looking at muscle volume in elite female sprinters. And they found quite a significant correlation between those sprinters who were quickest, so the most elite within that group, having much more muscle volume within the hip flexor group, so Iliaka, Soas, and rectus femoris. And again, they said that supports that you need to have strong hip flexors if you're going to be able to run quickly. And the theory behind that being that it allows for a kind of really rapid recovery of the leg during swing phase and allows you to have real good high stride frequency. So that's something that really stands out for me. Thinking about it, I'd probably think of rectus femoris potentially as more of a good strong knee extensor. But actually, when we're looking at running, there's a lot of research out there to support that actually predominantly is a hip flexor. And that's what we need to be thinking about within our rehabilitation of it, is thinking of its hip flexor role, really, rather than its knee extension role. It does a bit of both, but its kind of key role is hip flexion, really. And that, again, probably leads into kicking real key paper from Barfield in 1998 broke kicking down into six distinct phases. And the real key ones probably to look at within this, he calls it swing limb loading. And then your next phase is where you go to flexion at the hip and extension at the knee, that kind of essentially ball contact just before that ball contact. And we can imagine what huge demand that will be on the rectus femoris within the swing limb loading phase. The rectum's being loaded really strongly centrically as this hip extension and knee flexion occurring both at the same time. And then that, as you go into the hip flexion phase, is essentially initiated at the hip. So the upper part of that thigh goes into flexion. And then the load is kind of... shifted from possible to distal through the elastic and contractile components of the knee extensors to produce really, really quick angular velocities in the potential to 3,000, sorry, 2,000 degrees per second, they report. So you can see, again, what that rectum's doing. Essentially, in running and in kicking, it's initiating a lot of hip flexion first before then maybe it goes into its knee extensor role. So again, thinking about in our rehabs, How can we play around with that, having that information there? How can we get a lot of hip flexor activity? And then how does that distribute distally down the limb to the knee, really?

SPEAKER_02 8:29

Really interesting, because as you say there, it's not necessarily quite what we would automatically think of its role. And that's really important in rehab, isn't it? Because we're going to be looking at actually what we're going to talk about next is how we rehab that and a bit how we later talk about power as well. We're looking at a production of force with speed. So that's going to make our rehab quite specific. So let's dive straight into that then, Adam, in terms of when we're rehabbing an anterior thigh injury, how do we use those sort of complementary muscle groups to help with our rehab? And what are your thoughts around that?

SPEAKER_01 9:02

The best starting point is to think about the rectus femoris and what role it does. And it kind of doesn't have a hugely distinct role. It kind of picks up a lot of slack for other things. So if you've got weakness within that chain somewhere and another muscle group's not maybe doing as much as you'd like for whatever reason, whether that's kind of lack of attention to it in training, poor strength, previous injury in different areas, generally that rectum is going to pick up that load a little bit. So if we think we've had an injury within the rect fem, that's already compromised. Any other compromises throughout that chain are going to really impact it and increase its work. So thinking about what we just talked about, those hip flexors, iliacus psoas, are going to play such a huge role. And the more work we can do with them within the rehab process, the less strain and stress is going to have to be taken up by the rectus femoris specifically. if we've had an injury there. So thinking about it in that point of view, you can see why you need to train it. And we've kind of probably touched on that within the biomechanics. But other areas are abdominals. And there's a couple of proposed reasons for that. The first is looking at rectus abdominis and obliques as limiting the amount of anterior pelvic tilt, particularly during the toe-off phase in running. And the reason why this is proposed to be important is is that it helps assist in getting an optimal length-tension relationship in the iliopsoas. If we've got a suboptimal relationship here, we can see how that's going to increase forces at the anterior hip and ultimately subsequently demand in the proximal rectus femoris. So again, it's having to pick up potentially more strain if the other things aren't doing what we want them to do and managing positions and strain through there. And also Newman, which is a paper we'll touch on again later on, but they propose that if abdominals aren't kind of working how you would like and engaging properly, you're going to get excessive lumbar kind of extension moments and movements, especially in kicking, they report it. And with that, there's going to be a slight posterior shift to the center of mass, and therefore we're going to have to work even harder to get that hip flexion and that positive moment within kicking. We're fighting against an action that's exaggerating that eccentric moment more posteriorly, and therefore we're going to have to work harder. Again, the rectus femoris is probably going to have to pick up that demand, so the more we can do with that. And the final one is the adductors. And there was a study that was done looking at EMG activity in kicking, and they demonstrated that adductor magnus levels were really, really high, particularly within step kicking. And the time where it was at its biggest was again in that hip extension moment. So as we're trying to decelerate that upper thigh to then go into our positive moment. And again, if we think those adductors aren't performing what they should be in terms of that deceleration, we already know from what we've discussed that the rectus ferris and the hip flexors are going to have to pick that up. So if your reductor magnus isn't performing its kind of big, strong eccentric role, again, where's that getting shifted to? It's getting shifted to the rectus femoris. So all of these things in isolation might not sound like much, but if we've got a deconditioned athlete who hasn't performed a load of kicking actions, is detrained as a result of injury, yes, that rectus femoris might test really well, as we'll come on to later, But all these other things really need to be monitored and trained and incorporated into the rehab process to help prevent the risk of further re-injury.

SPEAKER_00 13:06

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SPEAKER_02 13:35

patient, we're doing really well with that and obviously they're like to get back to the sport that they perhaps were injured in. When we're looking at that stage, what does the evidence tell us in terms of return to sport criteria and what are we testing and how can we do that most efficiently?

SPEAKER_01 13:51

Yeah, so again, a really great paper for this was Chris Morgan and some of the guys at Liverpool Football Club who produced a bit of a case study on rectus femoris rehab within specifically kicking athletes, so footballers. And they kind of broke down their return to play criteria into three sections. So the first of which was looking more at flexibility and mobility. And I think it's probably important to point out here that sometimes that can actually look the other way. So Depending on what re-injury we've got, whether that's like a tendon injury, we might have had some lengthening actually at the area. So we might actually see increased range on that injured side, and that might be a negative. It showed that we've not restored the stiffness around that area, the actual true anatomy of that area. So interesting not to just think of it as right equals left or more range is better. Actually, more range on the injured side might still be a negative. We show we've not restored normal anatomy within our rehabilitation process. True healing, good in there. So that's definitely something to consider. Secondly, they looked at strength markers. And I think this is a really, really difficult area to look at because of some of the things we've talked about. So one of those is positions. It's going to be really difficult to get a good, proper strength marker of someone eccentrically at the hip. into those extension positions because the range isn't massive. So to really test that well is difficult. And also the speeds at which we're doing it is really difficult. So some of the research out there is in IKD, and that might be anything ranging from 10 degrees per second, looking at real true strength, to maximum kind of 120 degrees per second. If you're looking at kicking athletes, looking at that knee extension speed and things like that, We know that's up towards 2000 degrees per second, potentially in that kicking action. So can we say it's a reliable test and transferable to kicking? Probably not, but it gives us something to maybe give us an idea. And again, what do we look at? So we can look at kind of the angle of peak torque on IKD. Again, that might give us a little bit of information. So where is the athlete at their strongest point? Have we restored anatomy? Have we restored strength in the ranges that they're going to need it? So maybe looking at that as much as we can, but acknowledging that it's difficult. Hopefully we can get a little bit more information in the third set of tests or third kind of group of tests, which are those slightly more functional tests, things like double leg counter-movement jumps and hop testing. And some of the metrics that Chris Morgan and the group talk about in there, Rather than looking at things like just jump height, really looking at the key metrics for this sort of injury. So things like rates of force development, which is a measure of explosive strength or a kind of real true definition of that rate of force development is the speed at which the contractile elements of the muscle can develop force. So with that definition, we can see how that transfer into what we're wanting to see with running and kicking athletes. The active strength index, so with a repeated hop and things like that, or repeated jumps, it's a figure that describes the individual's capability to quickly change from an eccentric muscle activity or contraction to a concentric muscular contraction. So again, essentially exactly what we've talked about with kicking and running. How well are they able to decelerate that upper limb and produce a concentric action to get into the next phase. So those are the sort of things we can look at to try and take it to the next level. And finally, referencing back to Newman, and this is something that people like James Moore talk really heavily about, is trying to balance all the strength around that hip. So Newman would say that the hip extensors should be your strongest, best torque-producing muscle group and basing everything off that. So when we're going to return to play, if our hip extensors are 100% of that strength group, we should be looking to get our hip flexors at approximately 85% of our hip extension torque and our hip adductors at approximately 65% of our hip extensions. But again, we have to think if this isn't a compromised athlete, maybe these are our bare minimums. We know what help the hip flexors and the hip adductors are going to give So these are maybe bare minimums as opposed to our top targets. We want to work for them as a bare minimum, making sure all those other muscle groups in there are very well balanced, but also a really good level to help that rectus femoris if it's compromised. Brilliant, Adam.

SPEAKER_02 18:53

As always, some real gems of information in there. So for those listening, if you, I'm sure, want to learn more about this topic, then do check out Adam's masterclass on anterior thigh injuries assessment to rehab, which we've linked in the show notes below. So Adam, once again, as always, it's been a pleasure to have you on the podcast. Have a good evening and thank you very much for your time. You too. Thanks very much. Cheers, Adam.