Episode 222 | Your Built-In Benchmark: Why the Uninvolved Side Can Be Your ACL Rehab Guide

What is up, team? And welcome back to another episode on the ACL Athlete Podcast. I’ve laid pretty heavy into you guys for some long episodes. This one is going to be short and sweet, I promise. I’ve been doing some thinking with some of my fresh post-op ACLers. And this is something that I’ve discussed with them and have inherently taught them to do post-op. And this also might be after someone has an ACL injury. They come in during the prehab process. They’ve got that feeling of post-injury, or especially when they’re post-op, and this is what we’re working through. 

And I started to think about the process for them a little bit, in terms of just some of the things that I’m discussing with them in the session, and also for our remote ACLers. And the thing with the injury and the surgery is that a lot is going on. There’s pain, there’s swelling, there’s atrophy, your quads shut down, you’ve got an AMI (which is arthrogenic muscle inhibition), which is just basically this tug-of-war between getting the quads activated and awake. This basically disconnects the battery, or we use the Christmas light analogy, a normal functioning quad. You’ve got Christmas lights on the Christmas tree. It’s firing when you put the plug in. 

The difference here is that whenever you have this injury, there is also a neurological change. It’s not just this local injury to the ACL. There is this central spinal cord and brain changes, as well as locally to the quad muscle, the knee itself. And when an AMI sets in, that is something where when you plug in the Christmas tree, the lights, maybe only half of them come on, or a quarter of them come on. You’re just like, well, what’s the disconnect? And so that’s where this ACL injury is not only just a knee injury, it’s also a brain injury. Not to give you guys any idea of like, actually trauma to the brain itself, but more so of like, it’s just a neurological thing as well as it is a musculoskeletal thing. So that’s where it can make it complicated, and why do we have so much atrophy, why do we have such a hard time getting the quads turned on, and all these different pieces that. To be honest, y’all, we don’t know all the answers, but the thing is, this stuff happens after the injury and surgery. You’re also apprehensive to just do all these things, like to bend the knee, to straighten it, just because of there being a fresh ACL in there, maybe had a graft done. And then this is also not to mention the other concomitant injuries like a meniscus, MCL, maybe other procedures within this that also might make this more complicated; therefore, also maybe more restricted based on post-op guidance. Maybe you’re in a brace, maybe you can’t bend to only 90, maybe you can’t put weight on it. Or, it’s just one of those things that you’re also just going to be dealing with more, just symptoms overall, typically. It just makes it a lot. There’s a lot of factors.

And so early post-op for us in our restore phases, we are aiming for a quiet knee. That is, in a nutshell, what our goal is. While we might be working on some other secondary goals, the quiet knee is our main focus. We try to keep it super simple. We are trying to regain full terminal knee extension actively. We’re trying to get our flexion back over progressive weeks from 90 degrees to 120 degrees, depending on restrictions. We’re trying to get pain and swelling down, so our symptom profile is managed as best as possible. We are trying to get our gait restored. We’re trying to make sure our walking can slowly get restored over time based on your restrictions and weight-bearing status. We just want to make sure those quads can turn on. Those are the things that are going to encompass this, especially the early post-op phases. 

And a big thing we are trying to tackle, as you guys know, is extension and quad activation. And often the athlete is trying so hard to do the exercises, but it’s just not clicking due to a number of those factors I mentioned. I was thinking about this even during my own ACL rehabs, like this was still challenging for me, like even the second ACL, for example. You’re like, all right, I know the exercises. I got my quad to wake up before. Let’s do this again. But the thing is like, it just feels like there’s a disconnect. The feel of it. It’s like when you go to do an exercise sometimes, when you first start it, you’re just like, I just feel my joints, or I just don’t really feel anything. And of course, it depends on how many moving parts there are. Are there multiple joints, or is it just one isolated, like a bicep curl, for example?

But the thing is, we are trying to also have this mind-muscle connection for this, and that’s something that just can be very challenging early post-op. And the thing with these exercises is that you can try and give them all the “best exercises.” The ones that are like our go-tos, for example. You can give ’em the best cues, the best positions, the NMES device, for example. And it still might not feel like it clicks. It might be something that helps, maybe move it in the right direction, but it still doesn’t feel like it should feel. And any of you ACLers can relate to me. I know for sure where you’re just like, yeah, I remember I’m trying to do this, and I just feel my hamstrings and my glutes kick on, for example, when I’m doing a quad set. You’re trying, you’re looking at your quad, and you’re like, I don’t see any movement, I don’t see any activity. 

One of the things that this makes me think of is essentially coming around to the point of this episode today, which is this cross-education effect that comes up. The cross education effect is essentially this crossover effect, where you’re working on the uninvolved side, or if, for example, your left ACL is the one that’s torn and has been reconstructed, then your right leg is the uninvolved side. There’s this crossover effect, if you will, that research has shown where it’s more neurally mediated, meaning it is an increase in the brain-muscle excitation. There are these neural pathways. The body is wild, y’all, in terms of the way that it works, but it’s very neurologically driven. And the research shows that especially whenever we are talking more about strength levels, that strength training, the uninvolved limb can help keep the ACL-operated side strength up. It allows for it not to drop as much and also to regain that strength better. Again, not necessarily saying like you’re making all these strides with getting peak strength, but more so it’s a neural-mediated thing that helps to keep the strength on the involved side, the ACL-operated side up. 

This is what leads me more directly to my point for today, which is using the uninvolved side as a helpful proxy, in terms of finding “normal.” And this is something that we reference a lot with our ACLers because everyone’s always like, well, when is this gonna feel normal? When am I gonna get back to normal with this? Should this feel normal? This is something we get a lot of the time. And yeah, our protocol might say like, at this point you’ll be doing this, or when we do this, then you’ll feel “normal.”  But normal, as we know in ACL land, is quite a blurry gray area, and especially with something that has been injured, has been operated on, potentially. Of course, it’s going to be a little blurred. It’s changed. Therefore, we need to figure out what can we use as what can be a normal benchmark and what’s a feeling for you, but then also from a performance-oriented outcome as well.

And now some of you may be like, well, I’m on my second ACL, and it’s the other side, and that’s okay. Still use the uninvolved side of where you currently are. Let’s say, for example, you previously injured your right side and you’ve rehabbed from that, and your left side is now the current ACL reconstructed side. Well, continue using your right side because hopefully you have regained it to a point where it’s functional and doing your stuff. If not, then you need to tackle both of these things. But with that said, like with your first one that you did, still use that as your uninvolved side because the thing that’s going to be your involved side is going to be the ACL-injured and reconstructed side. So that’s what we are going to use here, and that’s okay.

The main thing here is that we are more so targeting the feel, or potentially even the look of it. And there’s such a thing to lean into with the feel of a movement or the feel of a muscle, the feel of a range of motion exercise that we don’t want to overlook because we’re not going a lot based on just like the look of it initially. Because when you’re trying to turn on your quad, for example, it’s a little bit more challenging. And the other thing, for those of you listening with only one knee that has had an ACL injury or maybe is multiple on the same knee, guess what? You can use your uninvolved side as a proxy for this process as well. You’re going to have one side that hasn’t had an ACL injury and one side that has had one or maybe multiple to it, and you’re working through your rehab.

Bridging off of this, what I’ll do is tell my athletes that your uninvolved side is going to be your gold standard. Now, one caveat here that I do want to share is that I want to disregard strength levels a little bit here for comparisons. Or maybe someone with just excessive hypermobility, for example. Just things are out of the norm, but then also strength levels, because the uninvolved side can have some drop in strength; therefore, we can’t necessarily say that’s the gold standard for you. But when it comes to things like your range of motion and things that are like a feel of muscle activation, then these are things that we can look at in terms of symmetry. But the other thing with strength that I want to specifically point out, and potentially some jump metrics, some dynamic tasks, is that we’re going to look at some symmetry. We’re going to look at normative values out there for your same age and population and maybe sport. And then we’re also going to be looking at it relative to your body weight. We need to be mindful of these things and especially when we’re using them as a proxy. Those are the caveats.

But here’s how this is going to apply practically for you by using the uninvolved side, especially if you’re someone post-op going through this process. I want to talk about some examples that are going to be helpful to hit home for this. This is probably the one that I use the most, and it’s going to be for knee extensions. It’s going to be for trying to get that terminal knee extension, looking at the heel pop, and range of motion as your comparison on the uninvolved side. You might lie on the ground, or you might just sit and have your back against the wall. Make sure you are not on carpet and you are on a flat hardwood floor surface, so there’s no give to it. Don’t do it on your bed. But what we’re going to do is have both legs out. And then we’re just going to allow for that uninvolved side to go into a quad set. And typically, you’re going to let your heel lift up a little bit, in most cases, for hyperextension. That’s our heel pop test, or our gold standard of what we’re looking for. Again, if you’re someone who has like 15 degrees of hyperextension, 20 degrees, then maybe that’s not going to be the thing that we’re targeting. But in the majority of normal situations, we’re going to be targeting somewhere in the negative fives to maybe negative 10, for someone with typical hyperextension. And so that’s what we’re going to be looking at, and your uninvolved side is going to be super helpful to be able to gauge that. 

And then the thing for quad activation is that I’m asking you to potentially feel your uninvolved side as it is doing a quad set. Again, you’re going to be doing a heel pop. They typically coincide as the same movement. And you’re going to try and connect that with that ACL-operated side or injured side. You’re going to try and do the right side, for example, if that is the uninvolved side, and then you’re gonna do the involved side, the left side. You’re going to go and hit that quad set, for example, or the heel pop, and see if you can get that rolling.

And a lot of times it’s going to take some reps, it’s going to take some time, and then try doing them together. Doing them one after another. Use your uninvolved side to help get that feel of it. And it’s something that I think is so simple, but oftentimes it gets missed. And even with my athletes here, sometimes they’ll be like, Oh yeah, I forgot to do that. And when we work on it, they’re like, oh, okay. They find the rhythm, and then all of a sudden, we’re starting to find a little bit more of uad activation, some extension. And it’s allowing us to connect the mind to the muscle to that feeling. I think a lot of this has some like of that cross education effect that I’m talking about, which is why I brought that up earlier.

I also think that it’s just something that our brains are so in tune with movement that, especially from a range of motion, from especially like a muscle working activation standpoint, that I think that there could be a lot of value in this that doesn’t necessarily get utilized a lot. We just kind of focus on the ACL side. That’s where all of our attention goes. We’re like, all right, come on, work. We’re just kind of looking at it, trying to see if that quad will even move a little bit. Sometimes it does. Sometimes we don’t recognize it, but maybe the hamstrings and the glutes are doing the work, and that’s one of the kind of faults or things to look out for with this. But if you can do it on the uninvolved side and be like, all right, can I get this close to the involved side? That’s going to be a huge game changer because as you continue to move along, that’s only going to get better. And guess what? You get the uninvolved side as something you can continue to compare it to.

Now, as we go into looking at things and feeling things, the feel is going to be important, but then also the look. We can compare this to the uninvolved side again. This is something we’re doing throughout ACL rehab. And we just gotta find when it’s the right time to compare it to the uninvolved side, versus some of the other measures we might have. For example, when we are doing a split squat or a lunge, a lot of times, if an athlete is starting off with this, or maybe they’re coming to me three months in, six months in, later on in the process, and I might just have them do walking lunges. That’s an assessment for me. Depending on whether they can get into those positions, but I’ll ask ’em to do it.

And what I’ll do is I’ll record from the side and I’ll look at their shin angles and I’ll look at their torso angles and do a qualitative assessment and see, alright, what does their shin angle look like? Can that thing get positive where it’s not just vertical, but it’s moving your knee past your toes on the uninvolved side? And then look at what it looks like on the involved side. That’s going to give me insight into, okay, like this person, what we’ll see, a lot of times that’s a common fault is the person wants to keep their shin vertical, or almost hits this brick wall when they try to move their knee over their toes. It’s almost like it stops. And then what happens is that their hips do a lot of the work. 

We want to get an idea of this and then start to be a detective and be like, okay, well, why is this happening? Is it weak quads? Is it pain in the knee? Is it a donor side issue that’s causing some resistance? Is it limited knee flexion? Is it something where it’s in the hip or maybe in the foot? We’re trying to play detective when we look at these things. Other things we’re going to be looking at include single-leg, jumping, cutting dynamic tasks. Video can be super helpful for this, and it is the things that we do here in person. It’s what we do remotely to be able to see this. But I encourage you guys to just. Record yourselves. 

Right now, I’m going through some rehab for my hip, and I record myself looking at different movements and being like, all right, how does this look side to side? If I’m doing it with both legs, like a squat, for example, or hinging, I’m going to look and see, like, all right, does my body look equal if I cut it in half, or does one side look like it’s leaning over? Does my hip do something weird? I’m looking at things if I’m doing single-leg stuff or one side versus the other, just to be like, okay, how does this feel? I’m personally like feeling how does my glute feel side to side with some of this stuff. How does my hip extension feel, how does rotating my hips feel side to side.

And then I’m trying to compare and see how I can get to my other hip, right? That’s my gold standard I’m looking at. And so don’t be ashamed of videoing yourself, guys. This can be super helpful in this process and super valuable. 

Another thing that I wanna say here is that we can compare side to side to see qualitatively via the video, how it looks from an assessment standpoint. But you can also break this down from your own standpoint on how it feels. One of the main things that I want to hit home here is that if you’re listening to this and you’re trying to get your extension back, you’re trying to get that quad activated, use that uninvolved side as a proxy, as a target for yourself, and at least you know you’re getting back to a place where this is what I was born with. This is exactly what feels “normal” for you. And that’s one of the things I find ACLers are always on the search for is like, what is normal? And while it could feel a little blurred, especially post-op, we want to give you some sort of direction with that. Use that uninvolved side as much as you can as a comparison. Don’t compare yourself to other people because other people have different genetics, different injuries, different grafts, all those things. So that’s the one thing you want to get away from is comparing to other people. Use your uninvolved side if you are looking for comparison here, and then ask your rehab provider to help guide you on maybe what some benchmarks and milestones, and criteria for you to hit, to help marry all these things together. But use that mind-muscle connection. Look at things, look at the video, but then also assess the feel of it on the uninvolved side, and that’s going to help a ton to help hammer that home for the involved side. I hope this helps y’all. Until next time, this is your host, Ravi Patel, signing off.