Limitations and Potential Benefits of Using Curved Treadmills for Gait Analysis and Retraining

Dr. Rachel Selina // #FitnessAthleteFriday // www.ptonice.com

In today's episode of the PT on ICE Daily Show, Endurance Athlete faculty member Rachel Selina discusses using curved, self-powered treadmills for running & gait analysis, including the differences between metabolic output on overground running, motorized treadmills, and curved treadmills. In addition, she talks about pros & cons of using curved treadmills for gait analysis.

Take a listen to the episode or read the episode transcription below.

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EPISODE TRANSCRIPTION

00:00 INTRO Hey everybody, welcome to today's episode of the PT on ICE Daily Show. Before we get started with today's episode, I just want to take a moment and talk about our show's sponsor, Jane. If you don't know about Jane, Jane is an all-in-one practice management software that offers a fully integrated payment solution called Jane Payments. Although the world of payment processing can be complex, Jane Payments was built to help make things as simple as possible to help you get paid. And it's very easy to get started. Here's how you can get started. Go on over to jane.app slash payments and book a one-on-one demo with a member of Jane's support team. This can give you a better sense of how Jane Payments can integrate with your practice by seeing some popular features in action. Once you know you're ready to get started, you can sign up for Jane. If you're following on the podcast, you can use the code ICEPT1MO for a one-month grace period while you get settled with your new account. Once you're in your new Jane account, you can flip the switch for Jane Payments at any time. Ideally, as soon as you get started, you can take advantage of Jane's time and money-saving features. It only takes a few minutes and you can start processing online payments right away. Jane's promise to you is transparent rates and unlimited support from a team that truly cares. Find out more at jane.app slash physical therapy. Thanks everybody. Enjoy today's episode of the PT on ICE Daily Show.

01:26 RACHEL SELINA Alright, good morning everyone. Welcome to the PT on ICE Daily Show. My name is Rachel Selina and I am with our Endurance Athlete Division, so both our rehabilitation of the injured runner live and online. So first, sorry that this is a little bit later. I'm in Southeast Michigan and we had some crazy storms come through last night, so I have no power, I have no internet. So I am currently at my sister's house, so a little bit of a travel today to do this, but I'm glad to be here. So today we're going to dive into using curved treadmills for gait analysis. It's a question that comes up a lot in our live and online courses, which if you're hoping to get into the live course this year, we have only one more course for 2023. So the next or the last chance for this year to do rehabilitation of the injured runner live would be in Knoxville, Tennessee, November 4th and 5th. Like I said, that's our last course for the year. And then we have another online cohort coming up as well. That one is September 12th. It starts so you can jump into either one of those or both of those at PTonice.com. 02:38 CURVED TREADMILLS FOR GAIT ANALYSIS So like I said, we get asked this question a lot as to whether or not you can use a curved treadmill for gait analysis. And so by curved we mean like the non-motorized curved treadmills, which are common now in a lot of CrossFit gyms. So they're self-propelled. Probably the most common one is the Woodway Curve, and that's the one that's become more common in CrossFit too. There's a Rogue branded one. That's kind of the official treadmill of CrossFit and CrossFit Games. And then there's also like the Assault Fitness brand has a Assault runner. In true form is one that has another or another brand that has the same like type of treadmill. So there's some different ones out there, but they're all essentially the same. Like it's not motorized, so it's powered by the athlete. And it has that kind of curved surface instead of the flat belt that we would be used to seeing on a treadmill. So the claim by kind of manufacturers about these treadmills is that they better reflect over ground running, mostly in terms of the self pacing. So when you're outside and you're running, you can just kind of spontaneously decide, hey, I'm going to speed up and start speeding up or kind of not consciously. Decide to do that and you speed up or slow down. So you can do that on the curved treadmills because they're not motorized or you don't have to like push a button to tell it to speed up or slow down. You can just kind of naturally do what your body would do. So they're marketed as being more reflective of over ground running. They're also purported to decrease impact and therefore reduce your risk of injury. Right. Claim that they promote good running form, good running technique, and then also that they cause more posterior chain muscle activation during running. So that's kind of all like if you were to jump on any one of those websites for those brands of treadmills and kind of read about what they say the purpose of this treadmill is, that's what you would find. When we take it to the research, though, one, there's not that much yet of just good solid research as far as like how running on this type of treadmill actually does change your running form or how it causes muscles to activate or definitely not yet. Like, does it reduce risk of injuries? We don't have that yet. 05:16 GREATER METABOLIC DEMAND ON CURBED TREADMILLS What we do see kind of consistently in the research is that there is a greater metabolic demand from using these treadmills. So like for the same, you know, if you were to do a 5K and you did that outside, you did it on a standard treadmill, like with a motor and a flat belt, or you did it on a curved treadmill, it would it would be harder in terms of there'd be more oxygen uptake. You'd have a higher heart rate and higher RPE for like the same pace on the curved treadmill versus the other ones. And so that's consistent. Like that has maybe not great quality evidence, but there is that evidence out there from the research. We also see on the curved treadmills that we do get a little bit of a reduced ground contact time. So that's the like the amount of time your foot is actually in contact supporting your body on the treadmill. And we tend to see a shift or just like a, I don't know, not not in everybody, but we see that trend to take pressure off of the rear foot, especially when we're striking and go to a more mid foot or forefoot strike when we're using a curved treadmill. So that's really all like, and not even super conclusively, but that's all that consistently we see in the research about using a treadmill like that. Inconsistently is the muscle activation piece. Like there's there's not solid research to support that you have more posterior chain activation. One of the studies that looked at that was actually not using a curved treadmill. It was just using a flat treadmill that was self powered. So in that one, they saw like a little bit more soleus activation and a little bit more rectus femoris activation. But like I said, we can't necessarily apply that to the curved treadmill because it wasn't on a curved treadmill. Like that just might be something about being self powered, but can't say for sure. It also happens when we're on that curve. So some inconsistent stuff like maybe they don't quite do what we what we think they do, but we're not just not quite sure on that yet. In terms of how we use them in the clinic or in the gym, right, like if you want to do a running analysis, is this a viable option to do so? Can you use this treadmill and still get good data? So I'd say you can get good data. We just kind of have to take it in stride with what else we know is going on. So just like on a normal treadmill, we want someone to have a period of being able to adapt to that treadmill if they're not already comfortable running on a treadmill. So what we mean by that is if someone's coming in for a gait analysis, we want them to at least have had exposure to running on a treadmill before we assess the mechanics on a treadmill. Otherwise, you're going to get a lot of inconsistencies because they're just not comfortable running on that surface. So the same thing applies here. We definitely would want someone to have exposure to running on this curve type of treadmill if that's where we're going to then assess the mechanics. Otherwise, we're just not going to see a gait pattern that really is consistent with how they would typically run. So you could use it to make sure they have that period to be able to adapt. So usually that's like three sessions on the treadmill. It doesn't have to be full like you run for five miles three times. It can just be like 15 minutes, three separate times of getting used to that treadmill before you try to do the analysis. The other thing is that we have research for motorized treadmills. 09:45 RUNNING MECHANICS & TREADMILLS We have that research showing that someone's gait on a motorized treadmill, a standard one, is consistent with what their pattern would be over ground. So we can take what we see on that treadmill and assume that that's what we also would see if they're running outside. And we just don't have that yet for these curved treadmills. So we can't 100% assume that the pattern that someone would be showing us on that curved treadmill would be what they would go out and run like over ground. The claim, and I wasn't really able to find where this was coming from, but the claim is that running on that curved treadmill is actually more similar to running uphill. So the one kind of caveat there would be if someone runs uphill a lot, like they're doing a ton of maybe trail or just like big ascents, then it might be more accurate because you can't really on a standard run. You could run on an incline, but that's the one case where it might be more similar to their over ground running if they're running uphill. But that's not like the majority of our people, especially kind of in that more traditional gym or clinic setting. So we have to kind of take it with a grain of salt. What we're seeing on the treadmill might not be 100% reflective of what we would see over ground. The other thing though would be if someone, say you're in that gym setting, if someone is only going to really be running on this type of treadmill, by all means then assess their gait on that treadmill because that's how they're going to be running. So if someone only runs during CrossFit classes when running is programmed and that's where they'll do their run is on that treadmill, then that's fine because that's the type of running that they're going to be doing. Otherwise, if you're going to use that curved type of treadmill for someone that's just kind of running on a treadmill, then that's fine because that's the type of running that they're going to be doing. Otherwise, if you're going to use that curved type of treadmill for someone that's just kind of normal, maybe recreational runner, I don't think it's pointless. I think we can get some good data. We'll probably be able to pick up on big, just like big faults going on. We'll still be able to see from that coronal plane if they're, you know, from Dellenberg, how their knee separation is, all of that we still could see. We just need to keep in the back of our mind that this type of treadmill might reduce their tendency to overstride, like to have their foot land far in front of their center of mass. It might reduce that, and it might also make them run a little bit more biased towards their forefoot or midfoot, which we might not really see, like they might overground be more of a heel striker. So I think we just have to kind of keep those in mind. The one other kind of big, big picture thing to keep in mind is if we're going to use that type of treadmill for gait retraining, like we want to start changing someone's mechanics, there's going to be a few gait retraining drills. There's going to be a few gait retraining drills that are really challenging to do on that type of treadmill. So the main one would be retraining cadence. When we're retraining cadence, it's really important initially that the runner keep a consistent pace. So usually that's why like a standard treadmill is super useful because we can set their pace, right, say we're going to set it, their comfortable running pace is a 10 minute mile. So we can set that treadmill to 6.0 and we know the belt's going to stay at the same speed. So if we're encouraging them to increase their cadence, right, to listen to that metronome, to turn over their feet faster, we know that they can do that without speeding up. Because otherwise the tendency, if you just increase cadence without being able to control that belt speed, is just to go faster. All right, so if we're trying to retrain cadence on a curved treadmill, you can see the speed, but you would have to consciously like work to keep that speed the same while you're also trying to consciously pay attention to a cadence. So it would just be a really challenging setup to kind of internalize that cadence and learn that really well. 14:04 CURVED TREADMILLS & OVERSTRIDING For some of the other tools, though, like the curved treadmill might actually be a good way to help someone who does over stride to start to learn what it feels like to keep their foot closer. So the curved treadmill would almost force them to not over stride because they keep over striding, right, that they're going to be landing higher up on that curve. They're going to just make the belt go faster, which is why that treadmill causes you to kind of keep your foot closer. So it could be a good tool for someone who does over stride to get on that type of curved treadmill and start to feel, OK, this is what it's like to keep my foot closer to kind of find that that more centered spot. But we would also need to make sure as they learn that that we make sure that transitions for them back to over ground running. And I think that's just the big thing, right? Like, I'm excited to see more research that comes out on these treadmills to kind of show us, hopefully, where where the usefulness of them is and how it actually does really change our mechanics. So we know best how to use that. But I think as long as we keep in mind that, you know, some of the things we see might not be 100 percent reflective of over ground. If we can also get a little bit of an over ground sense of what this runner is doing, we can use both of those together to make this still a really good tool for assessing and for retraining. So that's it. I'd love to hear your thoughts. If you typically use this type of treadmill, whether from like you personally run on it a lot or you do a lot of assessment on it. I'd be curious your thoughts. So definitely put those in the comments. And then, like I said, if you are hoping to catch one of our live courses, our last one is coming up in November. So feel free to jump into that. We'd love to see you there. All right. Perfect. Have a great weekend, everyone, and thanks for being here!

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