Episode 112 | Breaking Down Compound vs. Isolated Movements in ACL Rehab

Show Notes:

In this episode, we talk about compound and isolated movements for your ACL rehab. Which one is better and when? The human body is crazy good at figuring out ways to do a movement, even if you’re doing all the “right things”. This episode sheds some light on how you can be more targeted in your approach and also some important things to look out for in your ACL rehab process.

What is up guys? Getting straight into episode 112 today, which is Breaking Down Compound versus Isolated Movements in ACL Rehab. First off, what are they? A compound movement is where multiple joints are moving and multiple muscle groups are typically assisting on a movement. Let’s say, for example, a squat, a bench, or a deadlift. And then you have isolated movements. So that is a single joint movement typically, and usually one or maybe a few muscles assisting, but one is the primarily focused muscle group. A good way to think about this is a tricep extension, bicep curl, knee extension, like a hamstring or a leg curl. 

Let’s compare these. You might have a bench press which is a compound movement. You have a tricep extension which is an isolated movement, a pull-up versus bicep curl, a squat versus a knee extension, or maybe a deadlift versus a hamstring curl. You have compound on one side, isolated on the other, and movement exists on a continuum. Things don’t always fall into perfect buckets here. But compounds just think of multi-joint movements and then isolated as a single joint movement. 

And why do we care about this? Well, it’s super easy to compensate in ACL rehab, whether you’re a clinician, a coach, an ACLer who listens to this. You know what I’m talking about, where there’s compensations where you feel it other places, or you move kind of funky, especially whenever it’s post-injury and post-surgery in the early days because you’re dealing with limited range of motion, you’re dealing with swelling, you’re dealing with pain, and definitely, some strength deficits which will impact the way you move. You pair that with forcing a certain movement you’re not ready for. Well, this in turn leads to other muscle groups assisting or picking up some of the work and different movement strategies to complete that said task. 

The task can range from anything in your day-to-day, like getting up out of bed, going to the bathroom, getting off the toilet, being able to go up and down stairs, just the normal activities of daily living that we say. Those are one piece of it are functional pieces, if you will. And then there’s the whole specific to rehab where you’re working on squatting and hinging and maybe step-ups and all these different positions like running and being able to cut and jump. All those different pieces. Those are all different tasks if you will, or the exercises or movement patterns.

And those are the things that our muscles have to come together and our joints have to come together to self-organize to complete. And what I often hear, and this is where this topic really came from, is talking to ACLers who are like, they feel like their quads are weak and they say they’re doing everything possible. And even movements that we love to see and we’ll program for our ACLers, such as squatting, maybe it’s split squats, deadlifts, Bulgarian, maybe it is step-ups or even just different positions of movements, and that’s awesome. But, what are all these movements? Compound movements. Multiple joints are moving. Therefore, multiple muscles can also help to assist. And it creates an opportunity to allow those muscles to compensate, especially if we’re dealing with pain, swelling, limited range of motion, and/or a strength capacity deficit. 

One of the things I encourage you guys to do if you’re listening, is to check out episode 78 where we talked about movement compensations in ACL rehab. It goes deep into the research on how this can happen. And of the things that I want to bring back into this episode because it applies so much to the context, is that our body will find a way to complete the task. Doesn’t matter how. There are a number of athletes that I’ve seen who have walked in, who have ditched crutches, and they don’t even have zero degrees of extension and can barely bend their knee to 30, 40 degrees. And therefore, if they’re trying to walk, guess what? They’re going to figure out a way to do it. And it might be to hike the hip up, it might be to move the foot or the toe up and to be able to swing that leg around, or what we call circumduct or do whatever they need to be able to do the thing.

And our bodies are really good at doing these things, whether it’s the early stages, mid stages, or even late stages. We see it all across the spectrum. That’s why we have to be super intentional about being specific. Educating clients on why it’s so important and you ACLers why we need to move a certain way and the task and the goal of that specific task. Usually when I’m saying task, at least as of right now, we’re referencing a specific exercise or an outcome we’re trying to gain. With this said, and a big focus today is on the compound versus isolated-based movements, to be able to wrap our heads around, okay, like what do we need to be doing? And am I doing this thing? 

And it really brings to mind this story of what I talked to an ACLer recently about where she was like, man, I feel really strong in all these areas. I could do squats, deadlifts, all the things. And I asked her, I was like, okay, well, what’s your knee extension? And she’s like, well, it’s only 5 to 10 pounds on a single knee. And I was like, yeah, you might be strong, but your body’s figuring out ways to be able to do the movements and to avoid using your quads as much as possible. We have to dig into why. And these are things that we talked about in that previous episode, talking about interlimb and intralimb compensations. So interlimb compensation is shifting from the ACL or the injured side to the uninvolved side.

For example, when you do a squat, you shift from one side to the other. This is such a classic thing. Let’s say for example, the left side’s injured, then when you go to squat down, you’ll shift more to your right side to pick up the slack, whether that’s from the pain, limited range of motion, or it’s swelling. It might be because you have not had enough strength built up to feel comfortable with that, or it could be something that your brain and body have learned to do because they did it in the early stages. Then there’s the intralimb compensation which is shifting from not just the opposite side, but within the same side, but it’s a different strategy or muscle group that is doing more of the work. For example, that squat shifts from the knees forward, allowing both knees to drive evenly forward to maybe shifting a little bit more towards your butt, going back, and being a hip strategy.

Therefore, you’ll feel a little bit more glutes, and hamstrings versus your quads really helping out. Believe it or not, a squat is a great movement. It’s a great movement to be able to produce force and lift heavy weights and to bring that ceiling up if you will. But squats are not always the best movement to strengthen your quads. And I’ll tell you why, individual and anatomical differences, different levers. And let’s say for example, when I was at UGA working with a basketball team, a lot of those guys did box squats and not very many. If we did front squats, it would be to a box. But with that said, with a box squat because their levers are so long with a long torso and long femurs they inevitably always felt it more in their glutes and hamstrings because of physics and their center of mass. 

And so with that said, it’ll be person to person and the type of squat they’re doing as well as the levers. But in general, just because you’re doing the squat, sure, there’s input to the quads. Doesn’t mean that it’s going to work your quads and strengthen them in the way that you want them to be, especially if you’re dealing with deficits and you’re shifting more of that focus toward one on the injured side or toward the posterior chain, which is the hamstringing and glutes.

Now, I talked about a pretty cool study on this by Susan Sigward at USC and company in 2018 – “Compensatory Strategies That Reduce Knee Extensor Demand During a Bilateral Squat Change From Three to Five Months Following Anterior Cruciate Ligament Reconstruction.” Long title here, but lots of value in this study. Basically, when they watched athletes squat, it went from a combined interlimb and intralimb to adjust interlimb compensations from three to five months in the mark of testing patients in this research study. They went from not only shifting to the unoperated side but also to the glutes and hamstrings. But eventually, it progressed to where it seemed a little bit more of an even squat but instead, they shifted towards the glute and hamstrings only. They didn’t necessarily want to load the knee and the quad, they wanted to shift out of it. And this actually answers a lot of this question that, let’s say, for example, the call that I had with this ACLer where they were like, I’m doing all the things. I’m doing Spanish squats, I’m doing leg presses, I’m doing box squats, all these things, but kicking out 10 pounds of knee extension. And then you got to dig in a little bit deeper and be like, okay, well, those are all compound movements that our body can avoid loading the knee and loading the quad. I’ve seen it all the time. I see it every single week that most of my ACLers will try to do. But we have to constrain the movement and make sure that we build up capacity before we introduce these types of movements anyway. 

The big takeaway from this study was athletes will avoid their ACLR knee if they can. They’ll shift to that uninvolved side, and then eventually we’ll shift to an even if it gets corrected, and they might shift more towards the ankle and hip versus loading at the knee. Now, you might say, Ravi, I am doing an equal squat. It looks the same. I’ll video it and I’ll send it to you. Cool. The naked eye will trick you. And it can even look solid in a video. I’ve got plenty of them where it shows, man, if I were to just look at this, just from an analytical standpoint, it looks even, it looks solid. There’s no asymmetries from the visual aspect from left to right. But when I ask the athletes, where do you feel this? Tell me where you feel this, especially after they do more and more repetitions. They’ll either say more on the hamstrings and glutes more often than not. And then let’s say they’re early in the process. 

A lot of times they’ll feel it on the unoperated or uninjured side. But whenever it’s a symmetrical stance, a lot of times what we’ll do is shift to a glute and hamstring strategy. Nine times out of ten, most of the time, even with a step up, anything multi-joint, for the most part, unless it’s been specifically constrained and intentional, a lot of the times it will happen because the body is trying to find the path of least resistance. And when you have multiple joints and multiple muscles moving, this is something that will happen because our body self-organizes to just do the thing. We’re not thinking as much about being intentional about what places are moving and how much is contributing, especially when you have a heavier load on your back or you’re lifting something heavy, you’re just trying to do the thing.

Now, I’m not going to sit here and tell you guys, these are the problems. I’m always going to come in here and try to give you guys some sort of practical solution you can take away. So what are our strategies? Improving your local tolerance, then capacity, then movement strategy. What do I mean by this? Local tolerance means, let’s just take the knee, for example. We need to make sure that the knee can tolerate a certain amount of stress. And if it’s dealing with pain, then we got to make sure that we work that muscle and that joint to be able to work within limits that are tolerable. We need to build up the tolerance for it because therefore that’ll allow us to build up what we call capacity. Think about building up the tank and the ceilings and the floors to be big and to be able to fill that up as much as possible, and then being able to make sure the movement strategy is optimal as well.

A good rule of thumb is to think about local to global, so be a bit more isolated. And then work a little bit more into compound and global and combine that always with the local. And also move in a direction of building up the tolerance, building up the capacity, building up that peak strength, that ceiling, if you will, and then the rate, how quickly we can get there. That is a very reasonable framework that physiology and biomechanics show us. And the way that our bodies develop from those standpoints will play out to be true. 

Another strategy that we utilize all the time within our coaching is constraints-led coaching with movements. This is something where you are looking at manipulating the task, the environment, and the individual to get this specific outcome we’re looking for. For example, if we are just trying to do a simple knee extension machine that limits one joint and isolates the quad. The machine itself is the constraint. It is only allowing you to move one single joint, or work one single muscle. Now we know, and if you look at the recent study, even out from Aspetar that just came out recently. It shows that knee extensions are safe. Of course, there are always specifics of, all right, let’s do it within a reduced range to start, let’s see how the tolerance is. Please just don’t do a one-repetition max. You can do it, you can start with a light load, work through the range, feel the muscle work, and build up that tolerance, as I said. And over time you can progress this. And that’s how we’re going to end up building up our quads. No more of the knee extension machine not working. And if you want more detail on this, you can actually check the website, the ACL athlete, and look for the OKC or knee extensions are safe after ACL reconstruction blog, where Dr. Germ has broken it all down in terms of not only the stressors on the graft but also why it could be so helpful in order to build up our quads. So that’s where this constraints-based approach is going to be important. It’s basically being able to set up things and be able to cue athletes to a point where we get the outcome or the focus that we want because we are executing things in a way that is manipulating that task, the environment, or the individual.

A good example of this is, let’s say someone’s doing a lateral heel tap, or they’re elevated on a small little step and all they need to do is tap down their heel to the side. Usually, you’re on the ACL side, stepping down, and the uninjured side is the one that’s going to tap the heel. So there’s one working. What often I will see is that people won’t want to punch that knee forward in order to really work the quads. And they’ll try to shoot their butt back, do that hip strategy. One thing we’ll do is I’ll either get a dowel or I’ll get a foam roller or something that is going to block them. And they can’t touch it. I put it right behind their back and they had to stay vertical in order to do the movement. And that is forcing them to use their quad and their knee versus if I just take that foam roller or the staff away, then it’s something where they could shift back to touch their butt backward and just do the movement, tap their heel, complete the task, but not work the quads the way we want to.

And so this leads me to the next focus which is trying to get our knee forward over our toes. And now there’s always a middle ground with this, not too far forward, not too far vertical of your shin, and it depends where athletes are at. But we need to be okay with being able to do this, especially if we’re trying to return to things where you’re jumping, running, cutting, because your knees are going to go over your toes inevitably. And it is not going to explode. It’s going to be totally fine and it’s a part of normal everyday life. Just like going down the stairs or a part of sport, watch any sport. March Madness is going on right now. Watch them move. Knees over toes all the time and while they’re cutting and jumping and anything. We have to make sure that we prepare ourselves for doing this.

So with that said, our quads have a lot to do with that. And usually, if people can’t drive that over, it’s due to a limited range. Usually, we notice a lot of pain associated with not wanting to do that. They almost have this alarm that if you drive your knee over your toe, then that’s going to trigger pain because it’s pressure on the front of the knee. And then it might be some swelling issues. And then it also, more than likely, is a quadriceps capacity and strength issue. They can’t do it because they just don’t have the prerequisites to do so. And it’s probably the thing we see the most is that people are lacking that quad strength. For example, this athlete said they could do all these other things, but for example, they don’t feel like their quads are really strong. And then when we actually dove into some other things that require it, like running and cutting and jumping, were having a lot of problems with those issues. And that’s because that quadricep strength and some pain were still sticking around. So that’s where we need to make sure, are we refocusing and are we rebuilding that quadriceps capacity and that strength, and then once that’s improved, It’s about queuing.

For example, it might be punching the knee forward or using a foam roller or a target when doing a deceleration drill. Maybe it’s a single leg bound or maybe it’s a split squat and instead of a vertical shin, it’s, Hey, let’s punch this knee forward, or Please touch this foam roller in front of the foot in order to make sure we’re driving our knees over our toes in a manner we want to, to be able to drive more focus into the quads. Build the capacity first and then ask if it’s a movement strategy issue. 

This is something that I learned from Eric Mira. He is a brilliant man, and he is someone who talks about this regularly. But this is such a brilliant framework that instead of trying to rush a certain movement, especially a compound-based movement, let’s first build the capacity of that local muscle and joint. You know what, we could stick around and work on a little bit more isolated knee extension, quad work, hamstring curls, calf raises, and things of that nature. And we plug this in where we want to build it up to make sure there’s not as much compensation. And then hopefully if that stuff is like hitting the numbers, we need it to. Let’s see if it’s a movement strategy issue. A lot of the times what happens is, is that even when we see athletes later in the process, they’ve been dealing with these issues, we have to build up that strength. And what ends up happening is that they still might have some of those movement strategies. So that’s where the coaching, queuing specific movements will be helpful to be able to make sure that that strategy changes as well. Because our brain has been so used to moving a different way.

What are the key takeaways here? You do not have to pick between a compound or an isolated movement. It’s and not or, do both. We can do compound and isolated movements. But when starting out post-op and post-injury, it’s actually really solid to focus on the isolated pieces first and plug that in to allow the sum of its movements to do its job correctly. And so that’s where the compound movements can be valuable. A little bit later in the process, I’ve actually changed my philosophy. Before I used to be like, hey, let’s squat as soon as we can and ensure we want to maximize those reserves and limit deconditioning. But the ACL side might not be ready for it, whether it’s the pain, the range, the strength, all these different pieces, it just might not be ready for it, and that’s okay. Let’s focus initially on the local areas. Let’s focus on some of the isolated joint movements. Then eventually, once there are enough prerequisites built up, a certain baseline and they show you strategies that are helpful, then you can make sure that that is combined with some compound movements and have them both into your programming, which should be the way. At the end of the day, double-leg movements are going to help build that ceiling as much as possible because you’re going to be able to push as much force and load as much weight through it. You don’t want to do one or the other. 

My suggestion is actually to start more isolated and local and then be able to build towards a compound and then combine both. And if you start compound too early and you don’t have that capacity prerequisite, it’ll just lead to learning a different way to do the thing. I’ve seen it where ACLers will be told, “Hey, let’s start squatting, a week out just because you ditched the crutches, you’re doing really well.” But is it worth it to do that immediately and focus on it so much? I don’t know. I don’t think so personally. And this is after seeing hundreds of ACLers at this point.

Is it worth it when we could just build that thing up a bit more isolated? Let’s constrain some of these movements, and we don’t necessarily need you to start doing heavy deadlifts or squats immediately out of the gate. Let’s build things up. Let’s make sure that they build up the foundation of this process so that way you’re set up and not just using these movement compensations, but you’re more so being able to recruit the right muscles and the right positions that we want. The other thing that you can always do is evaluate, not only how it looks. Visually, you could take a video. You could see, okay, how does this look and what am I aiming for? But the other question that I learned from a mentor is to ask, how does it feel? And I’ve been using this for years. But truly, how does it feel? If you’re doing bicep curls and you feel it like in your shoulder, you’re doing it wrong. But if you’re doing a bench press and you’re feeling it in your chest and your triceps and a little bit in your shoulders, you’re doing the right thing. The same thing can be said about a squat. If the intent is to be able to work the quads, when you finish your working sets and you’re fatigued, where do you feel it? Do you really feel it in your quads? And does it feel evenly side to side? Those are going to be the things to ask yourself, not only how does it look, but how does it feel? And then this allows you to have a little bit more of a specific focus on where the stress is being placed and where we want it to be.

And that is always so key and so valuable as a coach, as a physical therapist, as an ACLer in this process as you’re trying to audit and trying to make progress day to day, week to week, month to month. Can we make sure that we avoid this whole compensation because it truly does exist? And there’s not a single person immune to this process, not a single one. It happened to me when I was going through it. It’s happened to any single person I’ve ever worked with, so we got to make sure we get in front of it and make sure that it doesn’t happen. If it does, we put strategies in place to make sure we tackle it. That’s what’s so key here. 

When you’re breaking down compound versus isolated movements in your ACL rehab, what is the most important thing to take away here? It’s to start with a bit more isolated, actually, build towards your compound. But don’t think that compound is going to solve all the problems. We still need that knee extension, we still need that leg curls to isolate the hamstrings, we still need calf raises to be able to isolate a single joint, and that’s what’s going to be key. Let’s combine both at the right time so we can set you up for proper positions, proper patterns, and more importantly, proper power and explosiveness as an athlete and as an individual. I hope this helps guys. If you have any questions at all, please send them our way through email or through Instagram. 

Thank you all so much for listening. This is your host, Ravi Patel, signing off.

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