Episode 246 | Two Cars, Two Lanes: Undershooting Training in ACL Rehab

What is up team? Welcome back to another episode on the ACL Athlete Podcast. Today is going to be a short one, I promise you guys. We are going to start with reading a message from one of our ACLers. They had an open set or an anchoring set to see what her true abilities were with the knee extension machine.

I’m going to give you the parameters of this and what she got and what she said. She did a single-leg knee extension. We only went from 90 degrees to about 45 degrees, halfway through that full arc of 90 to zero, seated, single leg. She did a warmup for double leg with 20 reps, two sets at lightweight, just to get the quad working, just to feel that, but not to lock out at full extension.

And then she dropped down to just going through a partial arc of that 90 to 45. She built up to basically doing five repetitions on each side. And the goal was for her to leave one rep in the tank, so that’s an RPE of 9, which is 90% if you can think of it that way. Or it could be basically thinking about one rep left in the tank or one rep’s in reserve. This is something where if she did five reps, she would aim to do a weight. She could only do six reps and could not do seven or eight reps of it. It’s very specific to get someone close to a certain failure point or relative intensity based on the amount of sets, the amount of reps they are doing. She had three by five on each side, building up to a weight she could only do a maximum of six times, but she’s only going to complete it five times.

On the final set, I told her to go to just complete failure. It was an open set. I wanted her to just rip out as many as she could because she was gauging those first two sets, especially, based on what she thought was the proper weight for doing five on each side. I wanted her to do that on each side, complete failure; no more can lift it to what the previous rep was. She did this, and then what she ended up doing is on the left side, she got to 85 pounds for five reps. And she failed on that fifth rep. Therefore, that was what her five-repetition maximum, if you will, would be for this exercise.

And then on the other side, she did five at 100 pounds and failed on the last rep. Obviously, there’s a little bit of discrepancy. The left side is the ACL-injured side. Of course, there could be bigger gaps in this. But with where she is, she’s in the later phases. This is great because the symmetry is closer to 90%-95% versus not. But then also we were able to see, okay, she could get to 85 pounds on the left side, 100 pounds on the right side. 

The other thing I do want to tell you guys is that every knee extension machine is going to be a little different. If you go to one one-knee extension machine and it’s 85 pounds, you could do a completely different knee extension machine, and the 85 pounds could be 45 pounds, or it could be 130 pounds. And that’s because of the design, the physics of the machine, the levers that are created, the padding, the seats, there’s so much variation. 

If you’re using the same knee extension machine, then that’s going to be a way for you to be able to judge going up and down. But there have been people we’ve worked with who travel, and they’re like, I hit 120 on this one, but before I could only do 40 on the machine at home. It’s just because of the way the machines are designed. That’s one thing just to factor into this. But before this was interesting that this athlete was doing lighter weights, even though we were building towards a similar style, intensity, three by five or a three by three, but we were building up towards something like this. She’s undershooting essentially what was happening. 

Let me explain what she had said after she did this anchoring set or this final set to failure. She said, okay, this made me realize I need to be pushing the weights harder on this specific movement. I think my brain still struggles with this machine because it was hard before, but now it’s a lot better. This was just her way of saying, I need to push myself here. The other thing, too, is that she said, I also haven’t pushed my right side in a while to test the max effort because I usually just match it to my left. This is something that I wanted to especially point out with this is that I’ll usually match it to my left, which would mean I just match it to my ACL-involved side. I don’t try to push my right side more than whatever the left ACL side can handle. 

This is something that I see a lot of times. It’s something that we even have to correct with our ACLers because sometimes they’re pushing a certain amount, and then we’re like, do something like this. We are essentially undershooting what it is that they could be doing, whether it’s on the involved side or the uninvolved side. What I see is that this can also happen for the uninvolved side. What I’m sharing here is that basically the ACler will use their involved side as the weight or the perception of what they think is right for the sets, reps, intensity, and design. They often undershoot it by a lot. As you could tell, if she had just done 85 pounds on the uninvolved side here, she could have busted out more reps because her right side (the uninvolved side) was stronger. But before, she was just matching basically what the ACL side could do.

I understand this from some of the thinking process around we need to get the goal to around 90% to 95% of symmetry of the uninvolved to the involved side. And so that’s something that we are always targeting in ACL rehab. But there can also be this fear that the uninvolved side will just keep getting stronger. You want to do “less” with it and then work the ACL side, especially. While sure, it can be a moving target, it’s also something we really want to avoid as we want that 90% to 95% to be compared to our strongest possible uninvolved side, and that is so key here. While some people might say, oh, the two flat tires aren’t necessarily the best analogy, I still think it’s such a great visual of this ACL process because we still see this quite a lot.

The idea is that when we are looking at symmetry, we’re looking at one thing versus the other; it’s a ratio. Therefore, when we are looking at one tire, if you’re looking at the side of a car and there’s two tires there. Of course, like if someone is uninjured, no issues, performing well. Both tires are full. When someone has an ACL injury, obviously, one tire will be full. One tire will be half full, if you will. If we’re using this from the standpoint of the strength.

What happens is that our goal is to try and keep one tire full and then the other tire also to get back closer to as full as possible. In that sense, we’re getting towards a 90% symmetry of the fullness of the tires. Do you follow me so far? What happens is that sometimes people will leave alone, the uninvolved side, and so then the tire air can drop; therefore, the strength of that can drop. If we have two half-full tires, then we have 100% symmetry. But they’re both not great tires. The thing that I wanted to share here is that if she was only pushing one side to, let’s just even say 75%, and then she pushed her ACL side to that same level, 75% full on both sides is still not fully full. We got 100% symmetry, but we’re not all the way there.

What I mean here is that we just want to avoid this trap of thinking that we don’t need to train the uninvolved side, or that we can just match it to whatever the ACL weight is. I think that is something that is a very important point in this process. And that’s why I also tell our ACLers that we want to think of each leg as its own individual when training versus using one to base off the other. Yes, we will look at symmetry numbers. But when you’re thinking about single leg, especially training, you want to think about them as two different cars in their own lanes. Your quadriceps, your hamstrings, your calves, your glutes, all the things, you want to treat them as individual cars in their own lanes. You don’t want to dictate the speed of one car versus the other car based on how each of them is going. You want to basically see how fast they can go in each lane, which, in reference, I’m speaking to them, being able to push their strength or whatever it is that we are trying to develop within that particular muscle movement, leg, whatever it is. But that’s the way to look at it, especially when we’re choosing something that is single-leg focus.

Let’s say, a leg press, leg extension, leg curl, split squat, for example, even for this athlete. We want her to be pushing heavier weights with her uninvolved side, and then her involved side is going to play catch-up with that. A lot of times, people think that it’s going to be something that will, over time, just continue to get stronger on the uninvolved, and then it is going to continue to keep this deficit. The involved side will never catch up. I promise you it will. It’ll take time. And it’ll also depend on your training history. For people who have been working out for a long time, well-developed quads, there’s going to be an easier chase, if you will, to be able to get there because they’re closer to their ceiling. Versus, let’s say a 15- or 16-year-old who has great genetics, never really weight lifted, it will be a little bit more of a moving target because that uninvolved side is going to keep getting stronger because they haven’t been exposed to it. There’s the newbie gains, there’s all the things that they will learn in this process; therefore, yes, it could be a little bit of a higher mountain to climb. 

But with that said, we want to make sure that we are comparing to the strongest side possible, versus it being just two semi-full tires. That’s just not going to do us any justice, especially when we’re thinking about trying to get back to sport and performing at the highest level. We want to make sure all of these physical qualities, strength qualities, power qualities, all the things are at the highest peak possible to make sure we are giving this athlete the best chance from a re-injury standpoint, but then also from a performance standpoint. That’s where I also encourage going to failure periodically, of course, depending on what phase athletes are in. But that allows us to anchor or create some open sets to know how much can actually be done. Because I think this is also a thing that athletes struggle with, is okay, like I’m just going to start guessing weights and be like, okay, this feels hard. If you do not have much of a strength and conditioning background, you’ve been pushing heavy weights for a very long time, working into repetitions where you’re like maxing out at three reps or five reps. A lot of times, what we find is that people’s perception of what is hard or what they can do versus what they can actually do is very different. This is something that can be super helpful, and it’s going to fail on maybe the last set. Again, if you have a unique situation with your knee, or certain movements might not be warranted, then you have to speak with your medical professional about this. But I would just encourage, if you’re in a good space to be able to do a five-repetition maximum of a leg press, leg curl, leg extension, single leg, that’s going to give you a decent proxy of okay, how far off are we? And then on your final set, go to failure. Let’s see where we’re at, and that can help you anchor things a little bit better and be like, okay, this is how much different this is to the other side. It’s not a perfect science. But it is a proxy, and research shows it relates to isometric and isokinetic testing. I think it’s something for us to consider in this process. 

That’s one thing that I did want to share is being able to go to failure so you can see what the true effort side to side is. Making sure we are not comparing to a semi-full tire or a leg that’s not fully at its peak. We want to treat each leg as an ndividual and train them individually versus basing one off the other for weights. But once we are able to take something to failure, then we can also make the proper adjustments on the right intensity. Versus sitting in this moderate area, which I’ve talked about in previous episodes, where people aren’t just getting the stimulus they need. They’re either just like doing some work, but it’s not enough. Once they find the right intensity, they’re like, oh wow, this is hard. I’m, fatiguing out. They’re also noticing the actual strength gains and muscle mass gains that they’re looking for. So that’s going to help us to get that intensity for the right reps, the sets, the volume prescribed, and be able to allow us to move the needle forward with matching up the right stimulus more efficiently.

I hope that this was helpful. I just wanted to share this example. I’m going to elaborate on some reps in reserve, some RPE stuff as we move along because I think it’ll be helpful. I’ll touch on some of the pieces here. But that way you guys can see this and understand and use it for yourself by anchoring is important in this process. And then that way we can make sure we are pushing the right stimulus. But then also making sure we are also using each leg individually versus comparing off each other and when we are picking weight to get stronger in this process. I hope that this was helpful. If you have any questions, please reach out. Otherwise, I’ll catch you guys next week. This is your host, Ravi Patel, signing off.