Unlocking Athletic Secrets Through Data- Dr. Trent Nessler

In this episode of the "Crackin' Backs" podcast, we're excited to welcome Dr. Trent Nessler, a sports medicine physical therapist with over 20 years of experience and an expert in ACL rehabilitation, injury prevention, and return to sport​​​​. Dr. Nessler is the brain behind the innovative ViMove+ technology, a tool that has revolutionized the way we assess and understand human movement in athletes and first responders​​​​.

ViMove+ is a flagship clinical product featuring medical-grade wearable sensor technology. It's designed as a screening tool to assess core and lower limb function, providing immediate, easy-to-understand objective data. The technology includes modules like the Athletic Movement Index (AMI) and Run, with ongoing development for modules targeting the Low Back, Knee, Balance, and Neck areas. These tools empower healthcare practitioners to evaluate various aspects of the body in a comprehensive manner​​​​.

The technology works by guiding users to place sensors on the lower back and legs, measuring movement, speed, cadence, balance, core control, and asymmetries. This approach provides a holistic assessment of movement, allowing for the screening of both healthy individuals and those returning from injury. ViMove+ instantly generates a report that identifies any movement dysfunctions, with TGA & FDA cleared objective data. Additionally, it suggests corrective exercises as recommendations, making it a valuable tool for injury prevention and rehabilitation​​​​​​.

In this podcast, Dr. Nessler will discuss how ViMove+ AMI has been used to assess movement in over 70,000 athletes and 5,000 first responders, unveiling surprising insights and patterns from this massive dataset. He will explore the increased risk of ACL tears following concussions and delve into the balance between leveraging data from tools like ViMove+ AMI and relying on clinical instincts when assessing individuals. Furthermore, Dr. Nessler will share his insights on the future of objective movement measurement and its potential to reshape sports medicine.

Join us for an enlightening conversation about the intersection of technology and healthcare, and how it's paving the way for a new era in sports medicine and injury prevention.

We are two sports chiropractors, seeking knowledge from some of the best resources in the world of health. From our perspective, health is more than just “Crackin Backs” but a deep dive into physical, mental, and nutritional well-being philosophies.

Join us as we talk to some of the greatest minds and discover some of the most incredible gems you can use to maintain a higher level of health. Crackin Backs Podcast

Transcript

Dr. Spencer Baron: 0:00

Welcome to the cracking backs podcast where we delve into the evolving world of sports medicine and groundbreaking technologies. Today, we are thrilled to have Dr. Trent Nessler, a pioneer in the field joining us to unpack the wonders of the I move. Plus, am I did you know that this technology has scrutinized the movements of over 70,000 athletes and 5,001st responders, uncovering astonishing patterns, like the increased risk of an ACL tear within three years following a disk a concussion? These insights are just the tip of the iceberg. Dr. Nestler will guide us through the complexities of bouncing vast data points along with clinical experience, and how this synergy led to the innovative approaches in treatment and injury prevention. Were also looking ahead with technology rapidly evolving. Dr. Nessler shares his insights on the future of objective movement measurement, and its potential to revolutionize sports medicine. Get ready for an enlightening conversation that will change the way you think about health and performance. Let's dive in.

Dr. Terry Weyman: 1:23

All right, welcome back cracking backs, hey, Trent, it's so good to actually put a face with the name and see you and I looking forward to this conversation. Because you've got over 25 years and clinical experience in the world of sports physiotherapy to rehab and biomechanics and all that good stuff. But what I'm really intrigued to talk to you about because it's such a hot topic right now is how have you seen this landscape evolves with the biomechanics? Therapy rehab, especially in the context of technology? Yeah,

Dr. Trent Nessler: 1:56

yeah. In First of all, thank you guys so much for having me on, I'm super excited to share this passion with you, and share kind of some of the stuff that we're doing. So looking forward to.

Dr. Terry Weyman: 2:07

So let's talk about the context of technology from the landscape. When you first started 25 years ago, hardly people were even using a cell phone, let alone, you know, the Dick Tracy watch. So for those older people, yeah. Yeah. So let's talk about some of that landscape where you've seen it go and then we'll get in more deeper. Yeah,

Dr. Trent Nessler: 2:28

you know, so interesting thing is, is that, you know, I've always wanted to quantify human movement in a meaningful and reliable way. And so when I first started, you know, I'm kind of dating myself here, but it was the big video cameras with beta tapes. And I'm trying to record people. And he laughed, because like, we remember those right now, trying to record people and trying to come up with a way of, of using 2d, as a way to quantify human moving, I actually went from that to a technology called Dartfish, which was used a lot in professional sports. It's used a lot in coaching. So I was using that technology. But again, it was a 2d technology. And as we all know, human movement is really three dimensional. And And sometimes what happens in a 2d environment, is that you would see movements on 2d that really aren't there, because you're not capturing it fully in in three dimensions. So, you know, I used Dartfish, for a long period of time, tried to find ways to truly quantify it was still struggling with that. And then Microsoft was releasing the newest version of the Kinect. And so I was actually able to get what is called an SDK or software development kit for the newest version of the Kinect camera. And we were one of the first 50 people to get this. And so we were using Microsoft programmers to program the Kinect, basically what we are doing with our eyeballs, and trying to do that with the latest technology. And unfortunately, that is a gaming technology. You know, and it's great for, for playing games and things like that. But when it comes to capturing human movement in a very reliable way, unfortunately, it's not quite there yet. And what we found was is that despite all of the time, all of the effort, all of the programming, we're still getting around a 20 to 25% error rate. So ventually I ended up scrapping that project. And then in 2014 2015, I came across a wearable sensor technology that was just coming to the market out of Australia. And this wearable sensor had been validated against the Vikon system biomechanics lab, and it was within 3% of that and it was actually developed by a physiotherapist in Australia to To quantify movement that he was seeing with his soccer players, you know, and there was that sideline discussion with the orthopedic surgeon like, you know, what are you seeing on movement versus what do you see on moving. So he was trying to find a way to really quantify that did a great job with the development of the sensor. And then what we did is we actually merged kind of together to develop a movement assessment that is designed to really assess the biomechanical risk factors for primarily was around ACL injuries. What we found is once we commercially launched it, and brought it to the market, and we started to use it in college athletics, and we started to use it in high school athletics use it clinically in the clinic. And then it started to expand into professional athletics. What we found is that when we correct those biomechanical risk factors associated with ACL injuries, what we were actually seeing as a reduction of over 50.2% of all our Shoemoney injuries. So ankle, knee, hip and low back, we were seeing that those same biomechanical flaws that we were recording that when we corrected those, that we were seeing a whole kinetic chain response to that, obviously, right, so. So that really was the first step. And you know, since we commercially launched that in 2015, we now have about 450 systems across five different countries. And we've collected data on over 80,000 people. And so, I've always kind of been a research geek in nature. One of the things I always wanted to do with this is create a database by which I could capture mass data. Because I felt I felt like we know a lot about human movement. You know, we know what the biomechanical literature shares with us, but in a biomechanics lab for them to collect 1000 subjects that may take them five years to do that. And so what I wanted to be able to do is create a system that reliably could capture and validly capture human movement on a large scale. And so what we found is that we're learning a ton about human movement. So now our system, the new version that we have, captures 3500 data points for every assessment we do. So across 80,000 assessments, we're talking about 120 million data points related to human movement. And the beauty of that is, is that it's, it's teaching me so much that I never know, you know, I'll give you an example. So we know from the literature, for example, that if you have a concussion, you're three times more likely to tear your ACL, upon return to play up to three years after a concussion. My question was always, why is that right? Because, you know, we have concussion clinicians who, you know, they'll work the vestibular system, they'll work on balance the work on their necks, and they'll, they'll get them back to play. The problem is, is that what we found, because we measure concussion, and we measure movement, is that folks who've had a concussion, the dynamic valgus, that they have with their knee is much greater magnitude, in the speed at which their dynamic valgus occurs that their knee is in much greater, greater magnitude. That being said, that's the number one risk factor for ACL. So what we then do is that we can implement what that knowledge into our concussion rehab, because 99% of the concussion therapists that I know, don't do single leg squats. They don't do single leg hops, they don't do multi directional hops. But based on that knowledge, we can now bring that into our concussion, rehab, and return that athlete to sport in a much safer, meaningful way. That's right, that's what I love. That's, you know, what it there's so much so much that we're learning about movement, that it just every every day, it just blows my mind, you know, and it's exciting because, you know, now what we're able to do is we're starting to break it down by sport, by position, by age by level of play division one versus Division Three versus pro, you know, all of these different factors now, that we can start to really like start to see like, what are the major things that are driving, not just injuries, but also performance? Because as we all know, Biomechanics is biomechanics, you improve biomechanics, you reduce injury risk, but you also drive athletic performance. Actually,

Dr. Spencer Baron: 9:57

before we move on I need to ask you about what you just mentioned about the valgus. You know, the findings of valgus? Position? Yeah, the knee and concussion. And the relationship. This is a first for me to hear this. Yeah. So let me just cut to ask you a little bit more about this. Yeah. So yeah, yeah. How did? How did you find this out? Did you do pre and post concussion? Did you do like, you know, a pre testing to identify what would normal valgus or normal movement patterns work? Great.

Dr. Trent Nessler: 10:37

Great. Yeah, great question. So, you know, the beauty of mass data is that you can filter mass data, right? So we have data on 80,000 individuals. So all we simply do is we take all of those individuals who have reported no history of concussion. And we look and see what their averages are on dynamic valgus and speed of dynamic valgus. Like I know, for example, normative values for single leg squat is around 20 degrees per second for Daniel exogamous, a hop is 100 degrees per second, a hot plant, which is a multi directional hop is 135 degrees per second. So we we know that from the normative data that we've pulled, and then we take those who've had concussion, and what we saw is that their dynamic valgus, and all of those single leg activities was much, much higher. And let me tell you this, the other thing that we're seeing, so this is really cool. So so our newest version, we are now quantifying how much pelvic motion, you have in a single leg activity. So not only can I measure how much does your pelvis move and like a Trendelenburg, or a corkscrew, but I can also measure the speed at which that happens. So so what I suspect is that there's a correlation to pelvic speed, lack of control of pelvic speed or fall of the pelvis, in labrum tears in the hip. That's what I suspect. Because we're seeing that same speed factor associated with ACL risks, we see that same speed factor associated with UCL tears, it would make sense that it also correlates to labrum tears. That said, though, the other thing that we are now seeing, because our newest version has just measured started measuring pelvic motion, is that that concussion factor also plays into pelvic control. So one of the things I'm actually going to talk about at the conference is the correlation of lack of pelvic stability, and center of mass displacement, and loss of balance, number one, but also the valgus stress that occurs at the knee. Because what happens is that when your pelvis falls, your center of mass goes off the force vector that it drives, it drives your knee into a dynamic, valgus position. So one of the researchers that I talk a lot with is a guy by the name of Timothy Hewitt in the world of ACL literature, he is the most published guy in ACL literature. And the cool thing is, is that we're seeing this in the mass data. And researchers are now starting to look at that. They're like holy cow, there's this whole pelvic link to or lack of pelvic stability link to risk of ACL injury. And because we've seen it so many times, now we know is that if you if your center of mass is displacing a large amount, and the force, the way the force vector is, it's just driving your knee into greater degrees of dynamic valgus. And the speeds are much higher. So the beauty of that is, from a training perspective is you know what to do. You know, it's the, you know, kind of like, I can talk for hours on this, you know, that the the amount of information that I have learned, related to human movement with mass data capture is amazing. And right now, we are capturing because we're across five different countries, we're capturing data to about two to 3000 subjects a month, a month. So my goal is, you know, in the next 10 years that we have data on over a million people, that would be amazing. Like, nobody's ever done that before.

Dr. Spencer Baron: 14:23

So let me again, I'm sorry, I just got to keep digging deeper into this. Yeah. So absolutely. We always were taught that, you know, simply, you do a Trendelenburg test. Oh, that's a weak gluteus medius. But now you're, you're finding that it's really it could be related to concussion. So how are you? How does that interplay?

Dr. Trent Nessler: 14:46

So yeah, yeah. So you know, the, I don't know the exact interplay. What I will tell you is that, you know, like when I teach my courses, I teach different levels of glute medius weakness, you've got your Trendelenburg, glute medius weakness, we have what's called a retro Trendelenburg, which is a little bit more glute medius weakness. And then we have a corkscrew, which is a Trendelenburg with rotation, so they're failing through the full, or the full length of the glute medius, which then then then guides me to a training perspective. So like in the course, one of the things I'm going to talk about is the spiral technique, which is a technique that we use with a CLS banned from therapy and where you wrap it around the limb, and you basically create an abduction and internal rotation stretch through the femur, so that they have to actively contract out of that. And a lot of that goes back to the motor learning aspects. A part of the principles that I apply is some of the same things that came out of like stroke rehab. And how do you create better motor planning in the higher centers? by by by pulling things into into those patterns? So they have to actively pull out of those patterns, if that makes sense?

Dr. Spencer Baron: 16:05

Okay, okay. Hold on, hold on. Alright, so I feel like I have so many questions for you on this. Alright. So why love it? Why would a increased valgus stress post concussion? Are the results of increased valgus? Stress post concussion? Yep. Cause ACL problems? Yeah.

Unknown: 16:30

Yeah. So not medial collateral or? Right,

Dr. Trent Nessler: 16:34

right. So the number one mechanism for so let me back up per se, the number one mechanism of ACL injuries is non contacting orientation. And so if you look at the research related to the limb position, at the episode of the ACL rupture, what the studies show in this comes both through a video, as well as CT scans, looking at bone bruising, and from bone modeling, bro modeling and bone bruises, they can tell what the position of the femur was relative to the tibia. Based on that, what they do is they go back and they do that bone modeling. And what they see is that the femur and the tibia are in this dynamic valgus position. So so dynamic valgus is the number one thing to measure for ACL risk. And that's, you know, the beauty of it is, is that, and I don't know why. But we, we started measuring that back in 2015. Now, that being said, that being said, what I've seen is that dynamic valgus is important. But more important, is controlling the speed at which dynamic valgus occurs. Because if you look at all of your physics formulas, and you look at a torque, and you look at power, and you look at force, they all have a speed component to it. So So you and I could stand up, put our knee and 20 degrees of valgus, and it wouldn't bother us. But if you did that at 250 degrees per second, you're probably going to tear something. So there is a component of speed to it. And the beauty of that is, is that the other piece of that that I'm now seeing is that the faster the speed, the more links in the chain that are involved. Because Because if you're controlling your knee, you're not controlling your knee, but you're drilling your hip and your foot, it's going to control some of that speed. When speeds are super high, what happens is that there's more links in the chain that are actually breaking down. Isn't that fascinating?

Dr. Spencer Baron: 18:52

Wait, I've been on for what, 10 minutes and I want to take the course I want to I want to go I want to get the equipment by the program and so, so. Okay, all right. Let me All right, Terry, do we have any other questions on that one? Because I already. Alright. Right. So, all right. Now, do you do an evaluation on like, just a visual observation and put them through some basic movements before you put the sensors on? Or do you put sensors on with your equipment? No,

Dr. Trent Nessler: 19:31

you know, so it's so funny. You know, I've had some orthopedic surgeons. So our test. It can it is at three reps and three one minute time test. And I've had some orthopedic surgeons tell me, Oh, my God, that's too hard. You can't you can't put athletes through that. If you're an athlete, and you can't tolerate that you probably shouldn't be on the field. I'm just gonna say yeah, but the other reason that we do that is that you You know, I'm a firm believer, that movement do get degrades Yes, over time and as you fatigue, and so the intent of the test, so you know what the test consists of, we do core testing. So we do a plank, we do squats, we do right side plank, left side plank, the most, highest EMG activity, and side plank is your glute medius. So I pre fatigue the glute medius, then what I do is I have you do all single leg activities, start with a single leg squat, so least challenging, go to a single leg hop more challenging, then I go to a multi directional hop, jump forwards, backwards, lateral and medial. Of those three of those four, the most difficult movement is jumping lateral, because you're taking your center of mass accelerating over you land, you got to stop your center of mass from going that direction, you bring it back to the midline. And at the same time, you get to control your knee from diving into a dynamic valgus. So the medial hop is one of the most telling of all four motions, because we tend to see the highest dynamic valgus speeds and magnitude with the medial hop. And they're doing that at the conclusion of multiple episodes of fatiguing of the glute

Unknown: 21:21

medius. Man.

Dr. Spencer Baron: 21:23

Hopefully you don't injure somebody while you're doing that. While you're testing?

Dr. Trent Nessler: 21:27

Well, I'll tell you, I'll tell you, you know, it's funny, because, you know, obviously, you know, the first year I launched, you know, I would have a lot of a lot of, of, of high blood pressure watching testing. So knock on wood, you know, we've done over 80,000 assessments, and we've not had any injuries, I will tell you, you know, I just tested the summer I tested 2000 firefighters, no injuries, you know, so, you know, the, the part about it, too, is, you know, you know, like we test a lot of first responders, with with the assessment, we do it in a lot of military personnel, you know, and there, there is variance, you know, you got your extremely fit individual, and you're not so fit individual, you know, in a firefight. Right. And, you know, the the guys, the guys who are extremely fit sometimes will come out with poor scores than somebody who's less fit in there. Like, why is that? You know, I've worked out all the time, like, I should be performing better than that guy. But that guy, the less fit guy, he's never gonna go into that fire balls to the wall he's never gonna run in. They're just all out, right? But the younger guy is, and that's what I'm measuring. I'm measuring, what do you look like when you're putting it all out there? Because that guy is all out there, the less fit guys all out there is very, very different than the physically fit guy who's all out. Yeah, that makes

Dr. Spencer Baron: 22:53

so you're predicting stuff. You're predicting injury before it happens, or in this case, ACLs. Do you want to you don't want to say that, hey, do you want to?

Dr. Trent Nessler: 23:04

I say I'm looking at risk, because you know, predicting something that never, you know, because from a research, you guys know from research term, really predicting something that never occurred? How do you know if I could do that I'd be a billionaire. And I

Dr. Spencer Baron: 23:18

might be on the road to being one at this point. So all right, I'm ready to not really I'm not really ready to move off of this, but I'm ready.

Dr. Terry Weyman: 23:34

Yeah,

Dr. Trent Nessler: 23:37

no way what and that is, quite honestly, it's one of the things I love about doing podcasts like this, because I love talking to people who get it so that we can get this information out there. I mean, this this is my passion for last 20 some odd years. In the beauty of it is it works. It absolutely 100% works. And I'm not selling pseudoscience here. No. Okay.

Dr. Spencer Baron: 23:59

You know what I have to ask what just one more one more question about between Dr. Terry and I, we probably get 100 questions for you. But all right. So let's talk concussion back to concussion again, and you're noticing that increase in valgus stress. And, but yet, you also would see that in an overuse injury void of concussion, right. Okay, so Right, right. What are your factors? Like? Is it just the the patient telling you I had a concussion last month or a year ago or 10 years ago or last week? Yeah. And that's the difference between what you're, that's what you're looking for?

Dr. Trent Nessler: 24:43

Yeah. So So, one of the things that we know from the research is that that that risk factor can go up to three years post concussion. So so we actually so as a part of our system, we capture a lot of demographic information. You know, for example, I know that if you've had a previous ACL injury, you're four times more likely to tear your ACL. So that's one of the factors that we pull in, we pull in the we, when we get concussion, it says within the last year, within the last one to two years, three to four years, five years plots. What I see is that five years plus we're not seeing it as dramatic of a change. But what I will tell you is that, you know, it needs to be addressed from a rehab perspective. So, you know, from, you know, that was my intent of putting that question in there, because everything that I do, I want it to have some kind of clinical implication, like, what do we Okay, so this is great information, but what do we do with it clinically? Like, how do we change that? And that's, that's really what the, you know, the, the, that's really, for me the reason behind the data, because how do we how do we clinically use that information to drive better go better clinical practice parents, so you want another you want another total brain brain build

Unknown: 26:13

on always go? Alright, so. Alright, so,

Dr. Trent Nessler: 26:17

so, so side planks, you know, you know, historically, I always looked at side planks as being the exercise that I would do to activate glute medius, because we knew the EMG activity of the glute medius is really high in that. The interesting thing is, is that if you start down at the foot knee ankle, in most people in a side plank, their ankles stay in a neutral position. And what we see is that some athletes, they will actually move into a supinated position on the bottom leg where their tibia drops down to the ground. We call it a tibial drop, simply their parent heels in their anterior tibia is not strong enough to stabilize them in a neutral position. What we've seen is that athletes who have a tibial drop in a side plank are more likely to suffer an ankle sprain, especially in sports like basketball. Oh my god.

Unknown: 27:15

Right? Right. And it makes everybody think about

Dr. Trent Nessler: 27:22

it, it makes total sense. So so go up to the shoulder, one of the things that we do is we have the person put their opposite hand up on their hip. So I can visually see that if their shoulders are rolling forward, the serratus anterior on the downward arm and the rhomboids are caught allowing their shoulder to come forward, which is going to increase their risk for labrum tears. Right from a side plank. Like who would ever guess that you get so much information from aside?

Dr. Spencer Baron: 27:56

Hold on, hold on? Did you put I gotta try. I'm tickled to death by this. Okay? Because I love this biomechanics stuff. So let me ask you, so side riding, and you have them with an arm out or on their hip?

Dr. Terry Weyman: 28:13

Yep. Right? Yep.

Dr. Spencer Baron: 28:16

Yep. Which is rolling forward that you

Dr. Trent Nessler: 28:20

so so the downward arm, okay. The scapula, she's not interacting in stabilizing enough against the ribcage. So the upper shoulder rolls forward, because the because it's a closed chain. So because it's a closed chain, this downward shoulder, the scapula is not stabilizing enough against the ribcage. So this rate is anterior and the rhomboids are not strong enough to pull up against that ribcage. Oh, that makes sense. Yeah. So it's, it's the downward it's the rate.

Dr. Spencer Baron: 28:53

So you said that there's a higher risk of surgery with tears, higher risk of labrum

Dr. Trent Nessler: 28:59

tears and rotator cuff tears? Yep.

Dr. Terry Weyman: 29:03

Thank you my exam every time.

Dr. Trent Nessler: 29:07

This, this is why I absolutely love mass data totally is why it's why I love having a standardized test across 10s of 1000s of people. Because you learn things about that, that makes it super meaningful. And you know, the interesting thing is, you know, had some pro teams that are like, Oh, the test is too long. Like, you know, I only want to do one or two of those movements. The problem with that is though, is that you're not you're not capturing the full picture. Like you're getting a snapshot. I will guarantee you if you do 10 reps versus 83 reps, that person is going to look completely different. Then they're going to look at the end of the test. So it's you know, to me it's about it's not just about it's it's multiple things number one is it's about the Teague factor, but it's also the sequence of the tests that we've put in there. We've put them in there for a very specific reason to start to pull some of these things out. So

Dr. Spencer Baron: 30:10

you're determining also, RT o RTPs are returned to plays from these, these biomechanic biomechanical aberrations, and and you're able to put them use that as a criteria now. Yes,

Dr. Trent Nessler: 30:28

yeah, in what I tell my orthopedic surgeons is it just allows us to make better and more informed decisions about return to play, I'll give you a perfect example. You know, one of the common measures that we use for return to sport is called LSI limb symmetry index comparison, the right side, the left side. And so you know that the assumption is that you're you are comparing that to a good limb. But we've all seen the athlete who jumps off a box and both of their knees collide together. That is 100% LSI. So from a return to sport perspective, that athletes free to go, they're ready to go. But we all know that that athletes at high risk. So one of the things that we developed is what is called in addition to LSI is we measure l Qi, which is limb quality index. So it's not just about the symmetry of the motion, but also the quality of the motion during the performance of the task. So we actually use an LSI measure and an L Qi measure in order to make a more informed decision. The other piece that we add to that is we have a 30 yard ACL de sel tests that we do. So again, with the sensors on, they do a max acceleration and D acceleration within 30 yards. And what it allows me to capture is not only what is the ground reaction force, it mid stance, not only what is the cemetry during stance times load during stance times, but also how are they controlling their foot as the foot comes into contact with the ground? But

Dr. Spencer Baron: 32:10

you're also for those concussion patients. You're also doing psychometric testing, I think I read somewhere on that. You're also you're doing verbal testing and other. Yeah, so

Dr. Trent Nessler: 32:24

yeah, so not not as much. There are concussion tests that you can do in what I would just for clarification, I am not a concussion specialist. This is something I came across. In in our data, we do have a measure that we use for return to sport after ACL, and that is called the Tsk 11. Tsk 11 is a Tampa ski of kinesio phobia 11 form. In the original studies were published by Paterno, which showed that if you score 19, or greater on that test, you are 13 times more likely to tear upon return to play. In addition to that, if you score 19 or greater, you're six times more likely to have a quad deficit, you're three times more likely to have an LSI that is off. So there's a lot of measures associated with a Tsk 11. One of the things that we've seen since we measured Tsk 11 is one of the movements that we assess is a squat, right? So with the squat, I take a plumb line, I drop this how I used to do it, I drop a plumb line right down the center of you. And one of the things that I was seeing is that a lot of my ACL patients who had been discharged, they've been returned to sport, when they would squat, they would still shift their weight away from that involved side. And in my question was always well, why are they tearing that contralateral ACL? Why is it that there's still a quad deficit when they've gone back to play. And so one of the things that I started measuring very early on, you know, back in 2000, probably about 10 was what I call a lateral shift. So since we started measuring it, the research is now called it a lateral displacement of the pelvis during the squatting motion, much more articulate than I but the concept is the same is that athletes get used to they build that motor pattern, that they're going to shift their weight away when they're squatting down, if that is not corrected, I've seen athletes in the gym squatting 315 pounds, with a three inch lateral shift. Now one of the things that we found is when we measure Tsk 11, and they perform poorly on the Tsk 11. They are much more likely to have a lateral shift, because they're there. They don't have the confidence in that side. In addition to that, we also see that when we do single limb performance with him, they have greater magnitudes of dynamic valgus and their speed. is a dynamic valgus or greater? What we've also seen that as we correct their lateral shift, as we correct their, their control of dynamic valgus and speed of dynamic dynamic valgus. That kinesio phobia goes down. kinesio

Unknown: 35:16

phobia. Have you ever Yeah, that I gotta use? I'm gonna use that forever. I've never even heard of that. Yes. Yes,

Dr. Spencer Baron: 35:24

your phobia. That's beautiful. Because just yesterday, we had a guy who was with the with the New England Patriots, he came in, and he was referred in and we I had him squat. I watched him squat. And he did. I actually, he, he bent forward a lot. But then I asked, I go listen, when you go back to the gym, can you take some video of you squatting with some weight? Because I want to see it challenged? And wouldn't you know it? He was doing exactly what you said. So we were Yeah, right. It was super obvious. But he didn't mention anything about it. And then right, that caused us to ask more questions, and we find out he forgot to tell us about an Achilles tear on the opposite side. So he's got some ankle mobility issue. But do you find out these things that they don't tell?

Dr. Trent Nessler: 36:13

Ya, yeah, so so so so you brought up a great point. So lack of ankle range of motion. A lack of dorsiflexion in a squat will drive you to the contralateral side. And so so so one of the things that we actually have in our assessment, the very last test that we do is called the inco. Test. And it's simply to clear the ankle as being the driver of the dysfunction. Because the other thing is, too is if you don't have enough dorsiflexion, when you land, you're going to land stiffer, which simply means the force that's distributed to the knee is going to be much greater. So what we what we like to do is we do the the ankle lunge test, to clear as a driver of a lot of the biomechanics that we see because and to to your point, you know, a lot of times what we see, so we actually measure forward flexion in our squat with the sensors. And the reason that we do that is that we find a lot of athletes who lack range of motion, maybe they lack range of motion of that operative knee. And visually, they want to see like they're going down. So what they ended up doing is they ended up creating more lumbar flexion in order to compensate for the lack of knee flexion. Then what that does is it throws them up for a whole l five s one issue in their low back, especially when they start squatting.

Dr. Spencer Baron: 37:42

This guy was six foot five, and we put a we put a foam pad, a thick foam pad underneath his heels and all of a sudden He squatted beautifully. Yeah. And that's what gave us the clue that there is some ankle movement. Oh my god, I love this stuff. Terror I know you want I am sorry, man, I just took over this whole conversation. Go ahead and ask them what you were gonna ask them. Okay, I

Dr. Terry Weyman: 38:05

forgot No. No, I do have a question because you brought up some, because I'm always going back to some of the simple stuff because it's a simple stuff sometimes that help the average doc even more simply talked about, like a lateral window, the best thing is a single lateral jump, you know, just to look for stuff. And then you talked about how to look at side planks different and how much information that can show the practitioner. Yep. So those are two, give me a third one that says that movement that most people will look at when single leg squat. So single leg squat, what we look for that would cause them to analysis and make some money they can incorporate in their office tomorrow. Can Do It talked about that? Yeah,

Dr. Trent Nessler: 38:50

absolutely. So in a single leg squat number one is symmetry between the right side and left side. You know, when I say symmetry, I mean depth of motion. in control of motion. When I'm looking at a single leg squat I'm looking at, do you have dynamic valgus your knee and if I don't have a sensor, and I can't measure it, I can still see it. Right? Not only can I see it, but I can see that if that's falling in quickly. Or if it's not, not falling in so quickly. So control of, of so one range of motion of that activity, the ability to perform the task number one, the range of motion during the task, the control of the dynamic valgus during the task, and just as importantly, and quite honestly, you know, I think probably for the you know, the first five years or so that I was looking at, at movement, everything was at the knee. Like I wasn't looking at the hips. And so the third thing that I would say that I've really, you know, focus a lot on and probably the last five to eight years is control of the pelvis. and not allowing not allowing for a Trendelenburg retro number or corkscrew corkscrew is by far the worst. So one of the things that we found in female soccer players, we did a study with Samford University in Birmingham, female soccer players. And one of the things that we found is that when we corrected a corkscrew in our female soccer players, we had a significant reduction in the amount of labrum tears surgeries that were coming out of that out of that particular program. So controlling of the of the of the corkscrew to me is also a really important piece. But really, it goes back to the pelvic control. Now, one of the things I'll tell you is super interesting, okay, so, so lack of pelvic control, what we're seeing in firefighters, is that lack of pelvic control, leads to increased risk for slips, trips, and falls in firefighters. Number one mechanism of injury. The other thing that we see is in police officers, lack of pelvic control, has a higher correlation to a police officer, who is going to lose balance when taking down a suspect. Because because the number one mechanism for injury in law enforcement is affecting an arrest. So putting their hands on somebody in arresting them, if it ever goes to the ground, if they don't have that pelvic control, that control of their center of mass, what ends up happening is they take somebody down and they fall with them, instead of controlling that fall. So so to me, the probably the thing that I've learned the most in the last couple of years is the correlation of the pelvis to the center of mass, and what that does for balance, etc. which I mean, I should have figured that out wrong.

Dr. Terry Weyman: 42:01

All right, on that on that subject, I'm gonna dumb it down a little bit single leg squats, how you perform them against the wall in open? Yeah,

Dr. Trent Nessler: 42:09

that's a that's a great question. So no, no stability, you know, very rarely on the field is anybody putting their foot up against the wall or anything like that. The other thing is, too, is that every time I go to do a single leg squat, they want to do a pistol squat. So pistol squat is great for your quads. It's great for isolation of your quads. But the position that we put somebody in is what we call the athletic position. So the contralateral limb, the knee is bent in the hip is either a neutral or slight extension. What the studies show is that that position, with the contralateral limb requires more glute medius contraction on the stance leg. So by placing the leg forward, because you got to think about it, as you place your leg forward, your center of mass drops backwards, it's part of the reason you get such a great quad contraction. On the other hand, most ACL injuries are occurring. When someone is not in that position, they're more in a running type of position or or cutting position. So what we do is, by taking the limb into slight extension, you bring the center of mass slightly forward. Therefore what it does, it causes an increase in glute medius contraction. So I call it the athletic position. That's what we refer to it as, but it's simply the knee is bent and the limb is in neutral or slight extension.

Dr. Terry Weyman: 43:37

The the non the non squatting leg is correct, correct? Correct. All right. So you're not doing that full leg pistol or not even dragging it behind. Yeah, just trying to keep it natural

Dr. Trent Nessler: 43:47

foot is off the ground. Yeah, that's another great point. The foot is off the ground. We do 10 reps, we keep the foot off the ground the whole time. Because, you know, one of the challenges that I had is, is how do you quantify loss of balance, right? Some people if I do this, it's loss of balance. Some people I have these big dramatic movements, that's loss of balance. So so in order to objectively measure loss of balance, I had to come up with a way to do that. And the way that we did that is if you touch your limb on the ground, or you touch something to stabilize yourself, that is considered a loss of balance everything else, because what we see is, you know, I was just testing we tested 100 firefighters yesterday, and you'll you'll historically have somebody that get on one side, they're like, Oh, my balance is horrible on the side. That's not typically a vestibular issue. It's not really a balance issue. It's a stability issue. Because as soon as they stand on one leg on one side, their pelvis drops or center of mass moves in, they lose their balance. So it's not necessarily a loss of balance as much as it is a lack of stability of the pelvis driving that center of mass to move

Dr. Terry Weyman: 44:59

how far down Now that you have a new squat, you

Dr. Trent Nessler: 45:02

know, it's a great question, I typically tell them within your comfort zone. Okay. And the reason that I use within your comfort zone is because when people do that, especially post operatively, sometimes they will modify the range of motion on their operative side, because that's people subconsciously figure out, this is where I can control my knee. And then and then if there's a variance between that on their contralateral side, then I know that that's something that we have to work on. You know, typically we're looking between 35 to 40 degrees. Okay. You know, our our data shows it's around average around 36 degrees.

Dr. Spencer Baron: 45:41

Wow. Oh, my gosh, Trent. Are you able to be candid about the FMS, functional movement? Because functional movement screening to me?

Dr. Trent Nessler: 45:54

Yeah, absolutely. You know, if you ask me to be candid, I'll be candid. So you know what, if you pull the research relating to the FMS, what it shows is that it is not a very good tool. There was a great there was a great study published by bushman. And what they did is they looked at over 1000 military personnel. And they did FMS is on and they found that those that were at risk, the area under the curves, and when they plotted it, the area under the curve was greater than 50%. What that simply means, statistically, is that 50% of the time they were wrong, they were wrong about quantifying them as risk. And they were wrong about quantifying them not at risk. So so the if anybody can look up this paper, it's by Bushman, I want to say it was in the American Journal of Sports Medicine, I want to see it was around 2010 2012 1000 military personnel, very large study, very meaningful study. And the authors actually said in the Detail section, in the author's comments, that if you are using this as a risk assessment in the military, you have got to be super cautious. You know, it's part of quite honestly what led to the FMS starting to like deviate and start to do the s FMA. And all these other pieces to it. At the end of the day, the FMS does not measure the number one risk factor for injury. And that is dynamic, valgus. Pure and simple. So if you go back to the literature, starting back is earliest 2000, all the way to 2023. And you talk to Chris powers, Timothy Hewitt, Greg Myers, like all of the major published people related to ACL risk biomechanics, they're all going to tell you dynamic valgus, the FMS does not measure that

Dr. Spencer Baron: 48:02

we had an interesting experience. How much Well, I

Dr. Trent Nessler: 48:10

I got about seven more studies, I

Dr. Spencer Baron: 48:11

can say if there's any one thing that I was looking forward to was Alice asking you about this, because what you're doing seems so much more advanced. And I always had a bad feeling about FMS, but they sold it well, and you had athletic trainers diagnosing and treating and that would put the, I'm sorry, not the athletic the strength and conditioning coaches put put, you know, they were using the system, you know, completely and the athletic trainers were having a little problem, you know, at the pro level and so it caused some conflict. But that we we saw a couple athletes that where they forced them to assume the the positioning that FMS suggested like in a squat, they never took under consideration, things like retroversion of the hip or anti version because we're not all the same. So you would have guys squatting with one like this was comfortable if their feet were in this position. And they ended up injuring you know, having hip pain from doing the squat the way the FMS told them to do anyway.

Dr. Terry Weyman: 49:21

So good on Spencer, look at that.

Dr. Spencer Baron: 49:28

I asked a course I asked Trent the question thinking that I have a funny feeling he's going to

Unknown: 49:34

rip off. I beloved, it

Dr. Trent Nessler: 49:38

was in a I'll tell you, you know, you know to the FMS is credit it was the first tool on the market that really quite honestly brought awareness of movement in the importance of movement. You know, I think you know, from that perspective, it really quite honestly it revolution eyes the way that we look at movement. That being said, you know, to your point, I think it was very well sold, it was very well marketed. And unfortunately, it's created a culture of coldness around it, that people just don't want to move away from it. And the literature does not support it. I mean, you know, if you look again, and again, and again, and again, there's multiple studies that show that the the predictive value, the positive predictive value of the FMS is is less than 50%. So you could flip a coin, and have a similar response. That being said, that being said, you know, with technology, that's one of the reasons that I was so adamant on creating a way to objectively reliably measure both with inter in inter and intra rater reliability. Because, you know, that's one of the big flaws with the FMS is inter and intra rater reliability, number one, and number two is sensitivity. How do you have a test that you can perform two reps? Like if you performed all three reps horribly on the first test, you perform the two reps? Well, in the last rep, horrible on the on the second test, you've improved 66%, but your score does not change. So from a sensitivity perspective, it's not sensitive enough. Whereas on our assessment, you know, we were looking at 3500 data points, and the the overall score is 560. I think it's 565 points. So you can you can make minor changes in your results and see it reflected in the scoring. All right.

Unknown: 51:51

I want

Dr. Spencer Baron: 51:52

to sleep well, tonight after this conversation. Let me I want to ask another question before we go into our, our rapid fire questions, but But hang on just a second here. I do want to know about dorsal VI? And I mean, you're this program that you're referring to that that we've been referring to this whole time is Vi move and Ami, is that right? Yeah.

Dr. Trent Nessler: 52:20

Yeah, it's it's the dorsal V, in its V move plus Ami. So the V plus move, AMI is the product that I co created with Dorset V GA V is they develop the technology, they develop the sensors, and the algorithm behind the sensors, etc. And then what we did is we co created the movement assessment, which is in for Dorsa. V is their number one selling product. Okay? And which has allowed us to capture this data. It's such a massive level.

Dr. Spencer Baron: 52:53

And actually, you just said something that I was curious about. Now, there are sensors you put up because I've actually seen like, like five or six years ago, systems that that did that were able to identify anthropometric or, you know, limb length and where your knees were and hips and all that without putting sensors on. But your

Dr. Trent Nessler: 53:15

Yeah, so So that goes back to the Kinect. So unfortunately, and again, I don't I don't I don't want to step on a time bomb here. But But what I will tell you is there are marker lists of BAE Systems that that program out the flaws that you don't that you won't see you won't see it because it's programmed out. Now the the Kinect, which is one of the systems it's used a lot for those has about a 20 to 25% error rate. But the programming, you'll never you'll never see it because it's programmed out. The the the most accurate measure right now as it is today is a sensor on the limb. And that's what we use, we use it's four sensors, one on thoracic spine, one on lumbar, and then one on each tibia. And from that we're within 2% of a Viacom system.

Unknown: 54:13

All right. Cool. Cool. All right.

Dr. Spencer Baron: 54:18

Okay, this is great, but let me okay, we're going to enter our rapid fire questions right now. Okay. And also it requires you obviously based on timing is it's going to be well, we won't be sounding off that bell but we Yes, but we are going to ask you for brief answers, but you know, it ends up we get hung up on some cool answer you gave and we started elaborating on it but all right, rapid fire Question number one, what is your favorite wearable? And why? Well,

Dr. Trent Nessler: 54:53

I'm gonna say Dorsa v, because it's taught me so much. Yeah, I hate to say that but it's it has taught me so All incredible. It's changed my it's changed my clinical practice immense. It's been the biggest change of my daughter Sophie.

Dr. Spencer Baron: 55:07

Okay. Yep. Number two, you're traveling. What? What is your wake up Good morning routine.

Dr. Trent Nessler: 55:17

I wake up at three no matter where I'm at.

Unknown: 55:20

Going to do right?

Dr. Trent Nessler: 55:23

Typically will get about an hour, hour and a half workout and then I'll try to hit a jujitsu class for an hour and then that's how I start my day by working out and choking people

Dr. Spencer Baron: 55:35

and then you go to heal them later in the day. Exact Terry go ahead and tell him why you gave me that look gave him that look. When you said three o'clock he gets

Dr. Terry Weyman: 55:45

him at three o'clock Don't worry. I want you to get up to Yeah, well we're in Vegas. You can guys can go do your three o'clock in the morning stuff on me for coffee and breakfast. Night.

Dr. Spencer Baron: 56:04

That's awesome. Number three. Since Dr. Terry was in the movie Karate Kid, his favorite martial arts routine is waxing his cars wax on wax off. What's your favorite martial arts exercise?

Dr. Trent Nessler: 56:20

What's my favorite martial arts exercise? I would say charge it up because it Yeah, because it's it's great for what we call a technical get up. So once you get knocked down popping up real fast. I'm an older athlete. So I've got a lot of these younger guys coming at me really quick. So I gotta be able to pop up real quick. So a Turkish get

Dr. Spencer Baron: 56:43

I got I got challenged by my girl to do Turkish get up and I look like I looked at my age. And I'm going to practice that more.

Dr. Terry Weyman: 56:54

Yeah, I just looked like a turkey

Dr. Spencer Baron: 57:00

question number four. When you're stuck in a rut, what do you do to get yourself up and out?

Dr. Trent Nessler: 57:08

You know what? I pray? I'm a big you know, I'm a big believer in a higher being in God. And you know, I look at the things that I'm thankful for. I've got a special needs child. I've got a young man 19 years old who's going off into PT school. I've been married for 31 years. You know? You can't give up the things that that are, you know, the blessings in your life.

Dr. Terry Weyman: 57:39

Love that. Don't get up for us got goosebumps from I will give her a Turkish get up or three.

Dr. Spencer Baron: 57:50

Thanks tryna got number five. What's the one habit you wish you could break?

Dr. Trent Nessler: 57:57

That I wish I could break. Be like, I am so obsessive about working out. I'm so obsessive about my jujitsu that you know, I don't give myself enough time to heal. Quite honestly, matter of fact, I'm sitting here I just had just tore my PCL, my LCL, my meniscus and I had surgery four weeks ago. So I'm, I'm in my recovery phase right now. So

Dr. Spencer Baron: 58:26

are you a patient of your, your? Are you patient have your vi move or your vi move?

Unknown: 58:34

Yep, yep.

Dr. Trent Nessler: 58:35

BFR. All of it. Laser.

Unknown: 58:37

Oh, my gosh.

Dr. Spencer Baron: 58:39

All right. Well, that's good, man. I hope you heal quick from that. All right, we gotta wrap it up. But I I, Dr. Terry, you know what I'm going to ask right.

Unknown: 58:52

Oh, we have him on again. Go ahead.

Dr. Terry Weyman: 58:56

Yes, we'll talk about that after the show. But so I do have one question. So I do want to do our wrap this up. Because, you know, you got to go to your rehab and all that. But yeah, you've had such an impactful. I want to hear some personal motivation. You have, you know, extensive, powerful career, Medicine Research, injury prevention, what's the driving force, and to push the innovation and improvement in this field? And before I answer that, I want to answer it for the person listening who may be either starting out in their career or is burning out.

Dr. Trent Nessler: 59:35

Yep. You know, for me, it was pretty easy. My father broke his neck when I was 10 years old. C 567. Verse fracture. Got him you know, I came out of PT school. We got him up and walking again. And he was in an automobile accident thrown from a car suffered a C one C two spinal cord injury. And my dad has never given up When my dad started a construction company, and then had his first spinal cord injury, in from from a wheelchair, built that into one of the most successful contracting businesses in Arizona, after his second spinal cord injury, still in a wheelchair, complete quad, he built it into one of the largest in the country. And, you know, he never told me, but what he showed me through his example, is that you can do whatever you put your mind to, you know, if you are determined enough, you're persistent enough, and you work hard enough, you can achieve anything. You know, one of the things that I would say is for the young people out there who are looking to get into the career is, you know, I have I have my CV that I send off to people, and I have my CV that I don't send off to people my my don't send off to CV is all the things that I want to accomplish, and I write it down and put it as if I have accomplished it. Because I'm a firm believer that if you write it down and you believe that you've accomplished it, and you're going to accomplish it, you will accomplish it. So I don't know if that answers the question, but it's, oh,

Dr. Spencer Baron: 1:01:10

it definitely answers and inspires. And I really appreciate that. I can't wait to meet you. And it'll be I look forward

Dr. Trent Nessler: 1:01:18

to I can't either. Yeah.

Dr. Terry Weyman: 1:01:24

And I'll see you for breakfast afterwards.

Dr. Spencer Baron: 1:01:28

We're gonna get you to do a couple of squats Terry at breakfast time.

Dr. Terry Weyman: 1:01:33

Oh, I'm starting now. And the side play go. There you go. Hey, Trent. It's an honor to see you. Thank you so much for being on the show and wait great words. And for everybody listening, so can't wait to see. How

Unknown: 1:01:49

can I say you guys,

Dr. Terry Weyman: 1:01:50

thank you.

Dr. Spencer Baron: 1:01:55

Thank you for listening to today's episode of The cracking backs podcast. We hope you enjoyed it. Make sure you follow us on Instagram at cracking backs podcast. catch new episodes every Monday. See you next time.