Jimmy: Welcome to the Physio Insights podcast presented by Runeasi. I'll be your host, doctor Jimmy Picard. I'm a physical therapist, running coach, and team member here at RUNNES. On this show, we have real conversations with leading experts digging into how we recover from injuries, train smarter, and use data to better guide care. Whether you're a clinician, coach, or an athlete, we're here to explore what really matters in rehab and performance.

Let's dive in.

Jimmy: Alright, Alex. Welcome to the Physio Insights podcast. How are you doing today?

Alex: Great. Thanks so much for having me. Really looking forward to this.

Jimmy: Of course. Yeah. Really excited to get you on the podcast here. You are working at my alma mater. So you're over at VCU, not too far.

I think you're the first guest that I have that's in the same state. So we should have done this in person maybe next time.

Alex: Yeah. There we go.

Jimmy: Yeah. Well, so for the listeners who aren't aware of you or your research, could you do you mind giving like a brief introduction?

Alex: Sure. So my name is Alex DeYoung Lemke. I am currently an assistant professor at Virginia Commonwealth University in Richmond. I have a background in athletic training, so I worked clinically for a bit. I got my undergraduate at University of Pittsburgh and then went on to the University of Virginia, where I got involved with research with the exercise and sport injury lab there.

That's really where my appetite for research grew. So I stayed on for my PhD and did a lot of research looking at musculoskeletal injury and biomechanics, some of which we'll talk a little bit more in-depth about today.

Jimmy: Yeah.

Alex: From there, I did a postdoctoral fellowship at Boston Children's Hospital where I got to work with a more adolescent running population to look at different injury patterns and the relationship to injury development. I did a brief amount of time at University of Michigan as a clinical assistant professor and then I wove my path down to to Virginia once more. So, yeah, currently doing research into musculoskeletal health and factors influencing musculoskeletal injury, recovery, and adaptations to training.

Jimmy: Kind of the two main topics I wanted to cover with you. First one being low energy availability. So you have a few papers that kinda deal with that subject. And then you have a lot of work more on the biomechanical side looking at IMU sensors, indoor, outdoor running conditions, and things like that. So maybe there's a lot of buzz right now around low energy availability.

I feel like we're talking about a lot more, which is great. We're becoming more aware of it as clinicians and how it's affecting our patients as well as performance. You were on that study with Kristen Whitney. You guys looked at the prevalence. Do you mind talking about that one real quick before we jump into the other one?

Alex: Sure. Yeah. So during my time at Boston Children's Hospital, I got connected with the amazing doctor Whitney, who was on this podcast previously. But she is in charge of the runner's clinic there. I was gonna say runs the runner's clinic, but that's always redundant.

But she's in charge of the runner's clinic there and is also now the co medical director of the Boston Marathon. So I was fortunate enough to work with her and the female athlete program at Austin Children's Hospital to start looking into low energy availability indicators, how we can measure those among a variety of athletes, and then look at how that impacts their performance and their health. So we conducted a study with the Boston Marathon field back in 2021 now looking at indicators of low energy availability. So primarily, this would look like menstrual dysfunction. This would look like disordered eating behaviors and bone stress entry history.

So those are kind of the the major three that we look for with low energy availability. Obviously, for males, they don't have menstrual dysfunction, but we can look at other markers of reproductive health of males. So we did a large comprehensive survey leading up to the point of the Boston Marathon, and we're able to tie back to their medical records as well as their performance data. And essentially, what we found was that low energy availability was extremely prevalent, not only among females, which has kind of been the buzz in the past about this only affects females, formerly known as Female Athlete Triad even. Yep.

But we actually found that this affected a good amount of the males in the race as well. And the most striking findings for us were that the presence of low energy availability indicators were associated with significantly impaired performance. So those, even when accounting for training behaviors, those with low energy availability indicators had worse performance overall. And the most concerning was about the injury data. So leading up to the point of the marathon, those with the indicators had a much higher risk of developing some sort of overuse repetitive stress injury that led to time lost from training.

And in the race, they had almost double the amount of risk of having a medical encounter at one of the medical tents. So this is a huge problem. Right? This is something that's really pervasive and is a huge concern for runners, not only for performance, but for long term health.

Jimmy: Yeah. And if I remember correctly, the prevalence was like over forty percent in females and over seventeen percent males or something like that.

Alex: Yeah. That's right. It was right around those numbers. Yep.

Jimmy: So yeah. So really high. So do you like speculating why like why do you think this the prevalence is so high?

Alex: Yeah. We're starting to dig into that a little bit more also. So the part of that surf hay that we looked at was really just kind of scraping the service the surface. But we started to look a lot into dietary behaviors, other training behaviors. So there's a lot of different contextual factors that we can start to tease out.

But, really, the reason why we wanted to look at it in this population is because there's kind of this pervasive narrative that leaner is faster or leaner is better. You know, when that's the the big media splash, then it's kind of taken out of context and and maybe giving folks the wrong idea about what's gonna make them successful for a large competition like the Boston Marathon. So, again, it it's not unique to the Boston Marathon. This is a huge problem, especially among endurance athletes. But, really, that's why we're thinking we're seeing this so frequently is just because there's this misconception potentially pressures externally to to look a certain way to to think it would positively affect performance, but we're actually seeing the exact opposite.

Jimmy: Yeah. And it's interesting because the misconception is is out there a 100%. Like, we saw we see it in this study. I had a patient yesterday who training for an ultra he's a high level, very competitive ultra runner training something over twenty hours a week, and he's actively counting calories, trying to lose weight, and has had just like back to back injuries, and he can't understand wrap his head around like this idea of, like, low energy availability and the effects that it will have on his training, which, yeah, which you showed in that Boston study that, yeah, the performance went down, injury risk went up is what it seemed like. And then this more recent study that you have looking at impaired response to training essentially.

Is that is that right? And do you mind talking about that one?

Alex: Sure. So are you referring to the other Boston Marathon one?

Jimmy: Sorry. No. The neuromuscular adaptation. Yeah.

Alex: Yeah. Absolutely. Yeah. So really quickly as a quick aside, we did another look into the Boston Marathon data to dig into training behaviors. And there was also kind of this misconception among folks that always doing more is better leading up to the point of the race, but we actually found that a relative reduction in training volume was associated with better performance.

So I really do think of those kind of concepts are tied together. Right? Like, trying to be leaner and always trying to do more are actually going to hinder adaptations that we would hope for as opposed to leading to their desired result.

Jimmy: Yeah. And real quick, it's it's there's there's some truth to it. Right? There is some truth to, like, lean like, being lean and running will like, performance often if we look at the finish lines of these races and the elites, like, they're very lean runners, and they're also training a a lot. So how do we how do we balance that?

Like we what we see because we're saying it's a misconception, but then when we actually look at the finish line like you you see it.

Alex: Right. I think that it is taken out of context somewhat though. Right? Because we know that those that are very elite are fueling adequately. They're just doing so much at a high level, but they've been training in that kind of, I guess, a gradual build up phase.

Right? So another component that we found from the training and performance paper was that those that had a really strong base performed the best. For those that had that, I guess, that ability to slightly reduce leading up to the point of the race were actually in better shape. So there is some truth to having that consistency and buildup, but there's also so many other factors that go into that. And and just taking that snippet of, like, a picture of what people look like is difficult too.

Right? Because a lot of folks that are more successful have a lot of history to that. Potentially, it's their career, and they're training constantly because that's quite literally their job. But it's taking out of context other stressors that folks might have in their lives that more training might not always be better for folks and actually might lead to higher injury risk and the the muscle strength and and other kind of anthropometric characteristics are all feeding into that profile of making folks more successful.

Jimmy: Yeah. I think it makes me think about Ryan Hall and his kind of journey with this. Yeah. Are you familiar with his story? Yes.

Yeah. And, like, how he talks about just, like, how even when he when he was competing at that level and he was set the American record for the half marathon that recently got broken, but held for a really long time. He was, he says, he's like, he was his least healthy. His testosterone was, like, lower than that of a woman's and all these negative health effects for training for the ability to kinda train at the level that he did. And so I think that's part of too is like, you know, this kinda separating things into performance, like elite level Olympic caliber performance and then health.

And what's the risk reward there? Like, are you willing to to roll the dice with that risk?

Alex: Yeah. Exactly. And I also think that there is some harm in comparison in in comparisons between what one person looks like versus another. Right? Because I guess comparison is the thief of of joy and health in this case.

Right? So if you're trying to look a very specific way, that might not be healthy for your body, whereas someone else who is still fueling adequately just happens to be leaner because of genetics or training behaviors or or many other things that feed into that model. Right?

Jimmy: Yeah. No. It's funny you bring that that saying up. That I said that to that gentleman yesterday because that he that was his approach. He was saying he wants to look like the elites that are winning the ultra races.

And, I mean, he weighs a hundred and fifty pounds. He's not a a large man. You know? But to him, it's like he is just comparing himself to that and thinking that that equals success or what he wants. And, yeah, I think it's a it's a pretty slippery slope there.

Yeah. So like, let's let's talk more about the negative side about this this low energy availability issue.

Alex: Yeah. Absolutely. So it was really based on the Boston Marathon project that we did with low energy availability indicators. Thinking about, you know, beyond just having the indicators alone, what is actually leading to this detriment in performance when accounting for training and and all these other factors? And so we know that low energy availability is linked with a lot of concerns with the musculoskeletal system.

We know that there's a much higher risk of bone stress injuries, especially major bone stress injuries like femoral neck, tibial stress, femoral neck stress. And we also know that those with low energy availability in general are weaker than their healthy counterparts. Right? Just because the energy allocated is kind of shifting more towards the major body systems to support basic physiological functioning beyond strength. Right?

So what we were really interested in was looking at studies that actually controlled for training factors and looked at changes in neuromuscular performance over time. So our thought was that, you know, if you control for a training cycle, is the muscular and the skeletal system responding in the same way that we would expect, or is there actually an impairment during that training cycle over time that's actually leading to reduced adaptations as we would expect? We did a large systematic review where we found 21 studies that looked at some element of neuromuscular performance. So we kept this intentionally pretty vague just because we wanted to see what evidence is actually out there. So we considered strength, lean muscle mass, other more functional performance measures like speed or performance on a specific test.

And then we were really interested in looking at how low energy availability conditions influence adaptations over time. Again, didn't have any limits to the amount of time, the types of training stimuli, simply just trying to get a really broad swath of what's happening in relationship to training in the neuromuscular system. And the findings were pretty striking. So of the 21 studies that we included, pretty much every single one of them looked at changes in lean muscle mass over time or fat free mass. And 10 fat 10 studies found that muscle mass was actually reduced in response to training or that there was no change over time, whereas those with optimal energy availability had increases or or or at least stayed the same.

Right? So this is really concerning because we would expect that with a training stimulus, you're actually increasing muscle mass. That's the whole goal. But this was not the case for those with low energy availability.

Jimmy: Yeah. And so with that specific finding, how how should a clinician take that? Like, if I'm dealing with this a patient like I described yesterday, like, how can I share this information with him to help him understand that?

Alex: Yeah. Absolutely. And again, I think it's just breaking down those misconceptions. Right? Saying that leaner is gonna lead you to better outcomes, but really the whole goal of physical therapy or any kind of rehabilitation exercise is to build up muscular characteristics, whether it's strength, whether it's endurance, performance, etcetera.

And so you can kind of show them this and be like, hey. If you're not fueling adequately, you're actually not going to see the outcomes that you want. It's going to prolong the amount of time that you have to come into my office, right, and and work with me and not really get back to your goals. And so I think kind of switching the narrative and and talking about how fueling is faster or how being strong is going to lead to faster and better results is really what we need to do to convey the importance to the athletes that we're working.

Jimmy: And how do you help, like, wrap your head around, like, that you're losing lean muscle mass while under fueling. But like

Alex: Yeah. So

Jimmy: We think you're gonna lose weight and you're gonna be get leaner by doing this, but this is kinda showing the opposite.

Alex: Right. And so this really gets to be a little bit more in the nitty gritty of exercise physiology. Right? So when you're not fueling adequately to support exercise, the common substrate that the body wants to use is glycogen. And when that's not available, it's going to switch to other sources, right, that are not as advantageous like fat or, like, protein based sources.

Kind of the background for, like, the paleo diet, right, of switching and, like, getting into that ketone usage. But in general, if there's not enough energy to support basic activity, then your body is literally starving, and so it's going to switch to another source to be able to produce an outcome. And so it's starting to actually start to break down muscle. Right? And so that's why we're starting to see some of this decrease in muscle mass is my best hypothesis without directly assessing it.

Yeah. That's generally what we're seeing in in kind of the trend in these in these.

Jimmy: Yeah. I had a I had a a dietitian that specializes this in the on in low energy availability on the podcast, and she talked about one of the reasons she got into specializing in this is that she was seeing having a lot of clients approach her because they're trying to lose weight, undereating, but they're gaining weight. They're actually, like, putting on weight and not not able to lose. And, yeah, it's this weird catch 22. You think you're doing the thing that's gonna help you, but it's actually has all these negative side effects.

So if we pick up back with this study and what you found, so you see you're not you're losing lean muscle mass with this with this. What other what other findings did you guys have there?

Alex: Yeah. A few of the other findings. So a lot of studies also looked at more individualized outcomes, and so we weren't able to pull the findings to get a comprehensive story. But kind of for the one off findings, we found that those that measured more like functional or sport specific performance outcomes, so for example, a timed mile test or some other kind of functional shuttle test that's related to sport performance, over time, those with low energy availability indicators had decreased performance, exact opposite of what we would want. Right?

The whole point of the training was to improve the performance, which we they did fine in the optimal energy availability conditions. And then some of the other one offs were decreases in strength over time, reduced limb circumference. So taking, like, girth measurements of specific muscle groups, and all of those were found to decrease. And then some other functional outcomes that we pulled that were related to neuromuscular function, not directly, but tangentially, were aerobic capacity. So v o two max performance decreased as well as glycogen availability.

So across the board, really seeing detrimental effects. It's hard because one study didn't look at everything comprehensively, and that's kind of the next step to see what are the global impairments. But across all of these 21 studies that we included, really negative effects of the neuromuscular system, which were striking. Yeah.

Jimmy: And then what did again, speculating a little bit, but, like, how does that then tie in with bone health?

Alex: It's a great question. So we know that bone health and muscle strength are related just especially for dynamic activities like running. Right? Because the the soft tissues around the bone help with shock absorption, especially muscles that are contracting to absorb some of the forces during running. And so if there's decreases in neuromuscular capacity, in strength, this is inherently going to lead to increased stresses on bone tissue.

And so this is a concern. Definitely a lot more work to be done in this area, and it wasn't directly assessed in these studies either. But starting to look more into the relationships between neuromuscular activation and adaptations over time in relationship to the injury risk is going to be huge.

Jimmy: Yeah. So that that that'd be a really cool study to see because it's like, yeah, we at least in my world, like the PT world, seeing tons of bone stress injuries, and that's been my focus with low energy availability is thinking about its effect on bone health. This study kinda really helped point out, like, hey. There's all these other effects that are negative and there's a lot of them associated with low energy availability. If we start thinking about solutions, you we didn't meant we I didn't I didn't mention talking about this study, but you have another study where you looked at education around low energy availability.

Do you mind talking about that one?

Alex: Yeah. Absolutely. Because I don't have enough time on my hands. Apparently, I did another systematic review as well. This one was specifically looking at nutrition based interventions to combat low energy availability indicators and to increase nutrition knowledge.

So with that systematic review, off the top of my head, I can't remember exactly how many studies we included. I believe there was somewhere in the 11 to 15 range, and we can we can fact check that. But with that study, we found that regardless of the duration and the number of sessions, providing a nutrition based education intervention was beneficial for a, improving nutrition knowledge, and also for those that actually look specifically at low energy availability indicators, it was successful in combating those negative effects. Right? So improving body image, improving understanding of sport related nutrition.

And so it really signaled to us the need to incorporate some sort of nutrition education intervention or giving some sort of information sheet about what the negative effects of low energy availability are in conjunction with a neuromuscular training program would be most beneficial for those to increase muscle strength, muscle capacity, etcetera. This hasn't been directly done, and this is something that we're really interested in pursuing. But kind of these two systematic reviews taken together, the findings are pretty important for translating to clinical intervention.

Jimmy: Yeah. And with those with the studies, I yeah. I know you didn't prep for this, but who is delivering the education?

Alex: Great question. So it varied across studies. However, some at least one person with some sort of nutrition background, whether it was a sport dietitian, etcetera, those were typically included in the overall intervention team, or they helped to develop the nutrition education materials. So there was no standardized nutrition education intervention across studies. They were all specific to each of the studies, but they usually had some sort of consult with sports dietitian or someone else very similar credential.

Jimmy: Yeah. I guess it all it just supports the idea about how we all need to be working together, collaborative. And it's something I've been working on in my clinical practices, referring to a registered dietitian with anybody who's got a bone stress injury or anybody who's like like this gentleman yesterday talking about, like, weight loss while he's training twenty hours a week. Like, anytime that flag goes up, I think we gotta refer out. It's really hard to try to like, personally, I know you're not in the clinic right now or anymore, but trying to have those conversations can be really, really difficult for someone like me.

So I just gotta, like, push them out and refer them to a good dietitian. And this study is great because it's showing us that, hey. Like, the it's gonna have a positive effect.

Alex: Yeah. Exactly.

Jimmy: I'd like to take

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Alex: I think the other really important thing to think about as well is the mental health component and the psychosocial aspects associated with low energy availability. Because a lot of times, it is kind of pressure from coaches, pressure from peers to perform a certain way or to to look a certain way or just kind of this misunderstanding. And so getting a really holistic team to help intervene where it's appropriate would potentially lead to better outcomes. Absolutely.

Jimmy: Yeah. This is a that's great. This is a little off topic here, but how does how would we take all this information and apply it to somebody who's, let's say, like, generally healthy but is trying to lose weight? Like, it sounds like they're they're putting themselves at risk just by doing that. Is that like what would, yeah, what would you say to that?

Alex: It's a good question. I think that it really depends on the context. Right? So I would say if someone is actively trying to recover from an injury, I think it would be important to dissuade them from that mindset at present. Right?

Because the body is going through such a major change, whether it's, you know, a repetitive stress injury or after a major surgery or something like that, like an ACL repair, the body's going through this huge rebuilding and repair phase that it would be really detrimental to start limiting caloric intake. And so understanding that weight loss may be a goal, but understanding when the body might need to prioritize a higher energy intake to support the body needs and recovery and overall health is gonna be really important. When thinking about you were talking about just in a general healthy population about weight loss.

Jimmy: Yeah. Let's say somebody the response. Yeah. Somebody that wants to lose 10 pounds, it's not it's not unrealistic that they that they could lose 10 pounds, like that kind of person.

Alex: Yeah. I think that the whole goal there would be a gradual reduction. Right? Because I think that a lot of the fad diets talk about cutting a lot of things out and to exercise a lot more. And if you're doing both of those things at the same time, inherently, you're going to be in this huge energy deficit, which, again, the whole goal of weight loss is a balance between energy in versus energy out.

But I think that the narrative should be a gradual reduction and changing small things at a time so that there's not this major spike or major decrease, that's going to potentially jeopardize physical health, especially if training volume is greatly increased in someone who's consistently training for something.

Jimmy: Yeah. Interesting. And then going back to those patients that are, yeah, actively recovering from an injury and dissuading them from doing this. It's funny because those the especially if they're an athlete, they're a runner, and now they're hurt, first thing they do is decrease caloric intake, and they really wanna stop eating and often a lot. So it's a yeah.

It's a, a again, another case to say, let's let's refer them out to the specialist to help them better understand those concepts. Yeah. Anything else on low energy availability you wanna touch on before we move on?

Alex: Yeah. I was gonna just dovetail really quickly on what you just said. So I was actually having this conversation with doctor Whitney earlier and she was talking about how for women who are undergoing sections, they're often given a nutrition handout sheet to tell them how much they should be eating, what breakdown of the different Yeah. Macronutrients they should be having in their diet to support their recovery. And that's just not standard of care in musculoskeletal health

Jimmy: No.

Alex: Practice. And so I think that that's something that should be a good push because, again, right, if someone is decreasing their sport, they think that they don't need to eat as much, but their body is actively trying to recover, and so they actually need more fuel than they really think that they need. And so I think this is something that is a huge opportunity to collaborate with registered dietitians and other folks who are qualified to provide that support.

Jimmy: Yeah. Because it sounds like even, like, a simple handout could be effective. It's hard, like, again, like, piggybacking on that, I will often tell patients, like, it's okay. Like, I kinda want you to gain weight during this injury. You're gonna come back a little bit faster by doing that.

I know you don't want to, and you're gonna be upset about it. But if it gets you training faster, you're gonna that that stuff will come back off once you start training again, like, without you having to try. But, yeah, if maybe if, like, having just a simple handout like you're describing could be really, really helpful with every PT patient, you just get hand this out with their intake forms. Yeah.

Alex: Right. Yeah. And, I mean, especially after screening for higher risk athletes that might be at risk for developing low energy availability. But across the board, I think that that knowledge would just be helpful so that folks don't accidentally slip into low energy availability unintentionally and then hinder their progress over time.

Jimmy: Yeah. And I think that, like, the unintentional or the inadvertent low energy availability seems to be, like, just as common as, like, intentional or more common than the intentional, especially with the the rise of, like, the ultra runners and, like, these very long endurance events where you just like, this guy training twenty hours a week. How can you eat enough to support twenty hours a week of training plus a full time job? You know?

Alex: Yeah. Yeah. And it's interesting going back to that nutrition systematic review very quickly. A lot of the populations that were included in those studies were collegiate aged students or student athletes, and a lot of the nutrition knowledge at baseline was very low. And so, again, they looked at the change in nutrition knowledge over time, which greatly increased with even just a few sessions of a nutrition education intervention.

So I definitely see the merit in a handout or very brief counseling on on appropriate eating behaviors to support sport.

Jimmy: Yeah. It makes it makes me wonder, like, you get all in the clinic, trouble cases, we'll call them, or patients that just don't don't recover, aren't healing. The injury is not responding like you you think it should. Like, how many of those patients are dealing with, like, this low energy availability, and that's what's driving the the poor recovery. Yeah.

Awesome. Alright. Let's switching gears. So you also do a lot of biomechanical research, and you used IMUs in your research. Before we get into the specifics, do you mind just telling everyone what a IMU is and why you chose to use them?

Alex: Sure. Yeah. So this is going back a little bit to my earlier work, but again, I think it does tie into low energy availability and overall musculoskeletal health. The reason why I got interested in biomechanics research is because with my clinical background in athletic training, I worked a lot with endurance athletes, and I got really interested in looking at biomechanical or movement patterns and how those related to musculoskeletal health over time, especially for really repetitive movements like running. So IMUs or inertial measurement units are essentially small wearable devices that are capable of measuring movements or other specific outcomes that aren't necessarily tied to a lab environment.

So it offers a lot of flexibility. Again, there's hundreds of commercially available IMUs out of the market. And so, really, it depends on what you're interested in measuring because each IMU, has slightly different capabilities depending on their actual measurement components. But, essentially, the types of IMUs that I work with most often are specific to looking at running biomechanics. So these would look like spatiotemporal measures.

So thinking about cadence or how many steps you take per minute, stride length, how long your stride is for each step that you're taking during a run. Contact time, how long your feet are actually in contact with the ground. And then there's some measurements that we take a little bit with a grain of salt just because they're not quite as good as if we brought someone into a lab to do a full setup, but some loading based metrics as well as pronation metrics when the IMUs are actually placed on the the laces of the shoe. So again, there's hundreds of different outcomes that it can measure. A lot of us are wearing IMUs to begin with.

If you're wearing like a Garmin or an Apple Watch or something similar, it's all kind of considered to be a wearable device. Right? That'll give you some metrics on how you're moving or what you're doing.

Jimmy: Yeah. Awesome. Yeah. And so obviously, this we're sponsored by Runeasi, which is an IMU, which maybe we'll talk a little bit about later. But go back to just like telling me or telling the audience here, like, what made you want to start using these as part of your research?

Like, what piqued your interest there?

Alex: Yeah. Absolutely. So I'll again take a little bit of a rewind here. So back in my master's program, I started to do to get into research. Right?

So I was doing my master's thesis, and I was really interested in gait biomechanics, so the way that someone was moving while they were walking, and how it relates to lower extremity injury. So that's kind of how I got started, specifically looking at ankle sprains and and chronic ankle instability. So we would bring folks into our lab where we had 12 cameras set up, a standardized treadmill in the middle, and then we would sit and watch people and ask them to walk as normally as possible while they were on this weird device with all these reflective markers kind of taped to their body and and ask them to move normally. So there's obviously a lot of inherent limitations even though this is kind of the gold standard. Right?

This is the the best way that we can measure how someone moves most accurately. I was really interested with my clinical hat on, thinking about how people actually move throughout their day to day activities. And especially when I was working with more endurance athletes and starting to dig into injury mechanisms and thinking about why or when they were having pain. Oftentimes with runners, it'd be like, I feel okay for my first few miles, but then around like mile four or five, I'm starting to have this weird pain here. I'm not really sure why.

Or for even longer distances as well, so potentially some fatigue mechanisms there. But that's really difficult to do in a lab space. Right? So, you know, it's just a little bit prohibitive for what we actually want to measure when thinking about musculoskeletal injury. So that's what piqued my interest in getting outside of the lab and into the wild as we like to call it, by using some IMUs to get a lot more data, get a lot more insight into what's actually happening when someone is moving outside, and how that might be relating to their injury mechanism or injury development.

Jimmy: Yeah. And so the the goal being there, like, yeah, saying, like, we know people are running outside. They're maybe not moving as natural when we're especially when we're sitting there. Well, I always tell people, I hate when people are watching me. I know I'm not running normally.

So, yeah, you wanted to say, yeah, what does it really look like? What what is these metrics? What do they actually look like out in the wild? So you did I guess, let's talk about that indoor versus outdoor study because that will piggyback right here.

Alex: Yeah. Absolutely. So when I was at the University of Michigan, we had a wonderful group of runners who were very interested in research. When we first started a new project, just because we had a couple of ongoing studies with Samsung and with Apple. We would open up recruitment, and we would be filled with recruitment, I think, within two days of it being open.

So huge running community in Ann Arbor, Michigan. But what we're really interested in looking at the comparison between the treadmill based running and outdoor running on a more standardized set route and distance as well as the indoor set distance on a treadmill. And so we already had that built into a running protocol, but we were able to add on some running specific wearable technology to look at the exact comparison between the treadmill based running versus outdoor running. So we had individuals set up with both, and what we were most interested in comparing was the actual metrics. So across a five kilometer run or we broke it up into thirds for three miles.

What did the metrics look like on the treadmill versus outside, and how much did those metrics kind of fluctuate throughout those segments of the run? So we're thinking about it about variability. When we set out to do this study, we were actually anticipating that variability would be a bit higher outside because there's so much more variable terrain. You're going off of a curb or running over, asphalt versus concrete. Right?

There's a lot of different factors. But what we were really interested to find was that on a treadmill, we found a lot more variability in running metrics compared to outdoors. We also found a couple of kind of striking differences between indoor and outdoor. So indoors, we found individuals took longer strides and had relatively longer contact time. So legs extending out likely further and then just spending more time on that treadmill belt.

And then we also found that a lot of their loading based metrics were higher, especially for the braking forces. So thinking about that horizontal component of of the ground reaction force. All those were indoor findings compared to outdoors.

Jimmy: So that's interesting. So what kind what was the treadmill setup like? Was it a, like, a standard, like, from the gym treadmill? Or was this like a flat tread what it what it look like?

Alex: Yeah. So we had a wood made a wood way treadmill. Yep.

Jimmy: Yeah.

Alex: Good. And we did try to simulate some outdoor components. So we had a fan blowing on them to simulate wind resistance and had it at a standardized speed and inclination as well.

Jimmy: Yeah. I I feel like I kind of assumed that I would have thought the opposite that as with stride length at least that it would have been shorter on the treadmill. What do you think happened there? Why do you think that happened?

Alex: Yeah. It's interesting. So we asked folks to run at a relatively comfortable speed. So we were using a Borg's rating of perceived exertion to try to just get like a moderate pace here. And so we didn't constrain the system in that way to say that everyone had to run at six miles per hour or whatever it was.

We did control for that in our assessments, but that was not found to be a major factor differentiating indoors versus outdoors. What I think was happening here was that inherently when we run outside, we have to adapt to our surroundings. And when that surrounding is adapted for us and held constant, we actually change probably more the way that we're moving versus outdoors is my hypothesis. So that's why we found that. I I'm not a 100% sure about why the stride length was longer.

That was actually not something that we were anticipating either. But in general, what we're thinking was that this was just an artificial running environment. The folks that we had come in subjectively said that they did all of their runs outdoors. And so that definitely could have been a factor that they just were not used to running on a treadmill belt. It felt unnatural.

They were changing up the way that they were moving.

Jimmy: Yeah. And can can we elaborate a little bit on this idea of like movement variability? So there was that like famous study with the blacksmith hammer. You know, are you familiar with this blacksmith hammer where it showed that like expert blacksmiths had more movement variability in their like swinging of the hammer versus, like, novices, like, your eye picking up the hammer, we would do a much more, like, tighter similar pattern over and over. So is there similar is it similar with running where, like, you the you want more variability?

It's better to have variability? Is it let is it worse?

Alex: It's a great question. It's kind of a u shaped curve or an inverse u shaped curve, I guess. Yeah. So having a lot of variability is usually identified in more novice runners just because it's it kind of signals a very uncoordinated movement pattern. Right?

That you would not be able to predict what the next step is going to be. So that's kind of a downside. And then having such tight or limited variability is also bad. Right? If you're hitting the exact same point every single time that you're running, then that inherently would lead to some chronic issues.

And so there is kind of this sweet spot in the middle of a little bit of variability, but not too much. So it's kinda it's called dynamic systems theory, which is the same concept of the blacksmith study that you're talking about. But what what were you thinking is that individuals that were on the treadmill had much more variability because it felt potentially more uncoordinated or unnatural in their movement patterns versus the outdoor condition where we did not find as much variability. That would be our hypothesis. So there's no perfect answer for this, but there's kind of the sweet spot in the middle.

Jimmy: Yeah. And just curious like with the variability that you guys were looking at, was it across all the metrics like cadence, stride length, like every metric you're looking at?

Alex: It wasn't every single metric, but there was quite a few that that showed up. So it was for cadence, contact time, foot strike, and pronation.

Jimmy: Yeah. Okay. And yeah. Really interesting. And then so the big takeaway though from a study is that we run differently indoors versus outdoors.

Yeah.

Alex: Yes. It's interesting. There was also a large systematic review and meta analysis that did compare indoor versus outdoor as well. Our findings didn't necessarily all line up with those, but we were looking at these very specific sensors and doing kind of an apples to apples comparison, indoor versus outdoor with the exact same measurement technique. Yeah.

So, again, what we're finding, it probably should be replicated in future studies as well. A lot of these folks were pretty experienced runners, and this was a relatively short distance as well, like five kilometers indoor versus outdoor. So getting into some longer running distances and looking at some of those outcomes, overground indoor versus overground outdoor would be of interest as well.

Jimmy: Yeah. And you mentioned that in your study, you guys did look at fatigue as a component to this where you compared first mile, second mile, third mile?

Alex: Yes. We did. And again, I would say that fatigue probably wasn't hugely at play here because we did ask them to run at a moderate pace. So we tried to control for that as much as possible and account for running speed in the models. But, right, in the future, looking at fatigue as a potential influential factor for variability and some of their metrics would be huge as well.

Jimmy: Yeah. And that's I guess that's, like, one of the beauty the beauty of the IMU is, like, yeah, you can go and just go do your full run. Like, with Runeasi,  I'll have patients like, you mentioned the patient who says doesn't hurt till mile four. I have them come early, put the belt on, and go do their four or five mile run and come back and check out the data. Yeah.

From clinical takeaways from that, like, obviously, it's like we wanna assess or if we if at all possible, we wanna assess how the runner runs. If they're indoor and they're always running on the treadmill, let's assess them there. For their outdoors, let's assess them outdoors. And were there any other clinical takeaways from that study?

Alex: I say that considering, right, what the habitual running location is is gonna be really important for tailoring assessment approaches, and also thinking about what are the goals. And so if we are thinking about, right, the runner that's having pain later on, looking at it outdoors is a little bit better. I I'd say actually the primary takeaway for this one would be pairing indoor and outdoor analyses to see how it changes and see and getting some more subjective information from participants. Are you having pain during this type of activity? Did this feel natural to you?

And then and kind of guiding your clinical assessment from there. I will say that my main take home from using IMU in general with my research is that I really prefer to have folks take things with them and run-in kind of their natural training environment and just where they habitually like to train because this is gonna give so much more insight when they kind of forget that they're wearing a wearable, and forget that they're running in general and being watched. You just get a lot more insights and a lot more data. The tricky parts, even with this study that we did where we just had those two distinct time points, it's just that. It's a snapshot in time, but it's not getting a ton of data over time.

So the more data that we can get and look at outcomes over time and how that compares to previous days, maybe when they're they had better sleep quality, etcetera, just using a lot more contextualizing information is gonna be really important. One of the things that we also have done in other studies is look at folks that are actively experiencing symptoms, low level symptoms of things like shin pain or foot and ankle pain, and looking at how those biomechanics change versus days where they feel a little bit better. So so much data to work through, but it can give you a lot of good insights into injury mechanisms and and ways to adapt training.

Jimmy: Yeah. Is that is do you have those studies published or are those coming? Looking at

Alex: So we do have a study published a few studies published on exercise related lower leg pain, and we had folks take IMEs with them over a week's worth of typical training. And what we did was we compared those with active lower leg pain versus those that were relatively healthy and did not have any current aches or pains and compared their biomechanics over that week's worth of training. And we found that those that had pain had much higher variability and longer foot contact times compared to those that did not. That was the main feature that stood out across their kind of habitual running.

Jimmy: Was it were those symmetrical too? Like, a longer ground contact time symmetrically, like, didn't matter on the injured side or the uninjured side?

Alex: Correct. A lot of folks had bilateral pain, and so we included both feet in those models.

Jimmy: Yeah. Interesting. Yeah. That's like one of the yeah. Using Runeasi, another IMU in the clinic, it's the asymmetry components that we get are often very helpful with patients because you can just clearly see it in the data for a lot of a lot of the patients, and it's eye opening to show them.

And then, yeah, it gives you a target, something to work on, something else to try to improve. There were so your other you you mentioned earlier that we're all wearing IMUs. We all have them on on us. You did another study where you try you looked at how accurate those watch data is. Will you tell us about that one?

Alex: Yeah. Absolutely. So as I mentioned, we were able to do studies with Samsung and with Apple when we were at University of Michigan. And so what we did was we looked at the wrist worn watch data from Apple, and we looked at those compared to those captured through the Runscribe wearable sensors that I was using at the time? Just when folks were wearing the exact or sorry.

When they were wearing both sets of sensors and doing the exact same run and we could line up the data directly, how do those compare? And what we found was there were some differences in the foot specific metrics compared to the Apple Watch. So what we're thinking is that with IMUs, it's a little bit specific on device location and the algorithm that's used to measure specific outcomes. So we found this most specifically for cadence and for stride length that those slightly differed. But again, this kind of makes sense.

Right? Because IMUs that are wrist worn are typically estimating what's happening at your feet based off of arm movement. That's why maybe if you're going for a walk sometimes, sometimes I'll use an Apple Watch, and it'll start blinking and be like, are you going for a walk right now? It's estimated based off of wrist movement. Right?

Whereas the other sensors are actually worn on the laces of the shoes, and so it's getting a lot more direct information from the target area of interest to measure the outcomes. So for us, it just kind of signals that you should be a little bit selective of the type of wearable, a, based on the validity of the device and how it compares to kind of gold standard metrics, and then, b, what kind of metrics are you most interested in? So I'm trying to get more specific with where devices are worn and what the outcome of interest is is going to be really helpful. Of course, it also depends on your goals. Right?

So if you're always wearing specific device, then you can start to get some more trend based data on what you're doing. If you're not as concerned about, you know, one or two steps difference compared to other devices, then it might not matter as much. But having more data over time can always be helpful. So it just depends on the specificity of what you're trying to get and and what you're aiming to measure.

Jimmy: Gotcha. So going back a sec, you where do you think we're going? Where are we going with all this research and all this data that we're getting with running an IMUs and especially because it's now, like, so consumer focused too where, like, my watch is telling me all this data. And then we can get more commercial grade stuff that's gonna be a little bit more accurate, tell us different metrics. Where do you see all this going?

Alex: It's a great question. I guess from my clinical perspective, I can see it just getting a little bit more refined to do precision medicine. Right? And this is already something that's trying to be done with some of the commercial devices. Again, I take these with a bit of grain of salt because we don't know exactly how they're measuring or defining certain things.

So for example, your watch might tell you, you need a recovery date because your body your body battery is at 10%.

Jimmy: Yeah.

Alex: It's like, okay. How did we come arrive at this magical number, and and how do we know that my injury risk is x number higher? So I do think that that's the direction that a lot of these devices are moving towards from a physical health perspective. I think from the training based data and the commercial watch availability or commercial IMU availability, it's just getting to refine training a bit more and trying to, again, augment what's already being measured, but just in a more specific way. So for example, a lot of these data are being used to look more in-depth into training behaviors Instead of just looking at time based metrics or, distance based metrics, getting a little bit more in-depth about to what is what is the intensity of the exercise?

What did this look like from a day to day basis and being able to track that over time? So a lot more data and a lot more power in the consumer's hands. I think the difficulty though is balancing understanding of the data and the action items taken from the data and what the devices are giving back. So it's hard because the onus is on the consumer to understand what's going on or to take that and use it, but there might be kind of this disconnect about what we should actually do with the data.

Jimmy: Yeah. And I think that's it sounds like we're we're we're now doing all this research. We're getting all this data, the all the studies you mentioned. But we're still in the kind of the early phases of, yeah, deciding what's relevant. And running is a complex thing.

We you know, everyone does run a little bit differently. There's, like, the self optimization theory where we think, like, hey. The body's gonna self optimize to the gate that's appropriate to you. How do you think about that with trying to, like, measure everything? Like, if if everybody is unique, like or do you do you think people that we all do adopt unique gate?

Or is there more of an optimal pattern?

Alex: Yeah. I I wish I had that answer because I feel like it would solve a lot of problems. I think this is the reason why I like the incorporation of wearable technology to look at how a person changes over time in relationship to how they're feeling. Right? Because it's impossible to say that a 180 steps per minute is the golden bullet.

Right? And then that's gonna solve all the problems to run with this specific cadence. I think, it's relative to where you're meeting someone and what their symptoms are and how they're presenting over time, which is why I really like the individualized IMUs because you can get a really good idea over time what this looks like. Aligning that with pain data, injury data, and recovery can be really helpful. Because if we're starting to see huge deviations within someone's running patterns, for example, let's say it's a cross country season and someone's running pretty consistently in one pattern, and then all of a sudden, you're seeing a really big deviation one day.

You might want to pull them aside and say, you know, what's going on? Are you having pain? Did you sleep well last night? What else is happening contextually to figure out what's happening there? We tried to do some of this.

This was really just a case series of cross country runners at UVA. We had a few folks that presented with pain and injury throughout the course of a season, And we did, in some cases, have data leading up to the point of injury, and we did start to see some fluctuations. But, again, these were kind of one off, kind of unlucky for them, lucky for us that we had the data leading up to the point of injury, but it might just give some insights into long term tracking and thinking about standard deviation and and variability in metrics over time for someone versus taking kind of a whole a whole team approach and saying, oh, you look different than runner b, and so then we have to adjust the way you're running.

Jimmy: Yeah. I I like the way you you're thinking about it. It's because also you the way you're you mentioned it, the runner is often experiencing it, and they they can you typically know, hey. I I feel like crap today. I slept for terrible.

But then the coach can show them, like, hey. Here's some data that, like, you're you're sloppy. Like, you're not looking like your normal self. You should probably take today easier. You should cut this run short or something like that.

And it's hard for like, runners are stubborn. We are often pushing through all of those signals our body telling us to slow down or to take an easy day. And the data can be, like, a a supportive tool for the coach or the clinician just to show them. And I I I do that with patients coming back, like, in their return to run, showing them the run easy data and say, hey. Like, I have data from you pre injury.

This is what you look like. Now you're 50% of that. We should probably be really cautious as we get back into running. But, yeah, it's like I mean, I get overwhelmed with all this data and all the the g p like, even for me personally, like, I've recently, like, taking a data detox. I'm running with a analog watch and no data because I just needed a break.

It's getting it's getting overwhelming. But

Alex: Yeah. And especially when, again, you know, if you're not using the data for anything specific, then, right, it's there, and it's nice, and it's flashy. And you can say that you have all these metrics, but if you don't quite understand them and you're not doing the research to figure out what it means or kind of contextualizing it, then it becomes really difficult. But I really like what you're doing with taking the pre injury versus post injury data. I think it would be lovely if we had that for every person.

Right? Because then we could really get a good idea over time about how to how to get back to that kind of pre injury level, but that's also really hard to accomplish if people aren't wearing IMUs consistently beforehand. But, again, it's just another tool in the toolbox. Right? It's great information when we're using it actionably.

Otherwise, it's yeah. It's data.

Jimmy: Yeah. I've been trying to so I'm in Roanoke, and Roanoke College has a I think it's a d three program here. And I've reached out to them to offer a free IMU gate screens with Runeasi, pre preseason for track or cross country. Just give baseline data and let's, like, get injury or data once they get injured. They haven't taken up me up on it.

Maybe you can see I'm like I was I was really surprised. So, like, I would do this for free. I just want I'm just curious and it's really interesting to see a healthy data versus now you're hurt. What is it? What does it look like?

Because that's always a problem when from a for clinical standpoint, when I see somebody and I get the IMU data, I don't know chicken or chicken or the egg, like, is this just how you run or is this because now you're in pain? But yeah. So beauty of the data, if we can get all of that, the holistic approach there. Looking into the future, what are you most excited about research wise?

Alex: It's a great question. I'm really interested in continuing on the path and kind of like merging my parallel research paths, I guess, of looking at low energy availability and musculoskeletal health in relationship to biomechanics and and kind of rounding out this whole picture. Because I do think that kind of where we've been in the research realm, and it's really difficult. It takes a lot of funding to do it, and it makes sense why it's this way, but it's been very select measures looking at a phenomenon and trying to build a whole picture around that. And even if we try to contextualize other research that looks at one element of an injury model and then try to merge it all together, it's just still not a complete picture.

And so what I'm really looking forward to doing is kind of merging my lines of research, getting a well rounded picture of musculoskeletal health and the factors contributing to that to design more specific interventions for individuals to help support their health and long term performance. I think that working with adolescents and young adults is a really great opportunity to interrupt and hopefully reduce the long term health effects of a lot of these conditions. So that's kind of where a lot of my research is going and and try to intervene early to hopefully improve long term outcomes and keep people active. Right? Because I think the whole goal is to preserve long term health, make sure people can still engage in sport and exercise the way that is is good for their bodies.

And so, yeah, a goal of mine, something that's exciting.

Jimmy: Awesome. Love it. Well, I look forward to to seeing what you keep producing. It's been great research, so keep it coming.

Alex: Thank you.

Jimmy: Of course. Yeah. And so we'll we'll wrap it up there. But for the listeners who wanna learn more about you, where's the best place for them to find you?

Alex: Yeah. Absolutely. So you can find me on LinkedIn. You can use my full name. Sorry.

It's it's a bit of a mouthful. A few last names. I'm on LinkedIn. I am also, I have my faculty profile page through Virginia Commonwealth University. We also just got our new lab space set up, so that's really exciting.

And so we'll have more coming out there. But, yeah, just stay tuned there, and we'll have more updates soon.

Jimmy: Awesome. Well, thank you so much for coming on. It's been a pleasure, and look forward to doing it again sometime.

Alex: Great. Thank you so much.

Jimmy: That's it for today on

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