We speak with Dr. Greg Lehman (BKin, MSc, DC, MScPT) to explore when biomechanics and posture are important and when they’re not. Greg also shares current research on the relationship between biomechanical factors and pain, challenging common beliefs of both patients and clinicians.
You can also view our short video on why perfect posture doesn’t exist.
Katie Yamamoto: This is episode two of Functional F1rst podcast, where we speak with leading experts in the field of functional health. I’m Katie Yamamoto from Functional Media, and today I’m speaking with Greg Lehman about posture, biomechanics, and pain.
Thank you for joining us today. Can you please introduce yourself?
Greg Lehman: I’m Greg Lehman. My background is in kinesiology. I have an undergrad, and a master’s in that, and spine biomechanics. I then went onto chiropractic school, college, here in Toronto, and they were great because they let me do research, and teach at the same time. Then I went back to physio school after that. And so, I’m primarily a clinician, and then I also teach a course on the side.
KY: So, what got you interested in biomechanics and pain science?
Even when I was quite young in biomechanics school, we knew that the biopsychosocial was important. So, I always tell the story, it’s a bit silly but, during an ergonomics class I was writing a paper on central sensitization, and phantom limb pain, and stuff like that, because we knew then, that pain was not just about posture and form, and technique, and forces, and loads. Then when you’re a clinician, it’s humbling because so many people don’t get better and it doesn’t always make sense so, you’re always looking for other explanations. To me, melding pain science with biomechanics has to be done because that’s how people work. So, you can’t just do one or the other. They have to go together.
KY: Can you discuss some common beliefs among patients and clinicians regarding posture biomechanics and pain?
The biggest one is that we think that too many people need fixing. That biomechanics are really important, our posture is extremely important. And then, it gives the patient or the clinician the idea that there’s something wrong with them, and that whatever that is wrong with, say it’s a tight muscle here, or a weakness there or a slight shift in their posture over here, is what’s causing the pain and it doesn’t make sense. So, maybe posture, and technique, and form are really important under high load conditions. Our strength is important if you’re worried about a tissue being damaged, but it doesn’t make sense how strong someone is if they just have pain walking around, or they have pain sitting. How could strength or stability really be that big of a deal? So, that, to me, is the biggest shift. We’re always looking for flaws in our patients, and then trying to correct those, and I don’t think that any of that is really necessary.
KY: So, you said that posture and biomechanics can be important in high load conditions. Can you elaborate more on that, and when they are, versus aren’t important?
So, when biomechanics and posture might be important is, I, kind of, separate them into five crude categories but maybe we’ll just focus on two. High load activities, I think that biomechanics are pretty important. If we go and I jump off a roof, there’s probably a better way to land because there you’re talking about actual tissue injury, and your biomechanics and your form, can really influence tissue injuries. So, dynamic knee valgus, which can overload the ACL and cause it to fail, posture’s pretty important then. But maybe for patellofemoral pain syndrome, where you’re not really breaking the knee cap, posture gets less important.
Or, the other area where I’d say postures important is a habit. So, I’m sitting slouched, that’s fine, that’s cool, I’m leaning back, my back doesn’t hurt, but let’s say my back hurts when I flex it, and then for some reason, I always flex my spine during everything I do. So, I keep persisting into the pain, maybe learning to have pain. There the biomechanics are important because it’s a habit and I keep aggravating it. It’s not that flexing is bad, it’s not that there’s one right way to sit, it’s just that I keep pissing it off, and I just need to give it a bit of a break.
KY: And does the research support this?
Totally. Yeah. I mean, high load activities, that’s where biomechanists are awesome. Where tissues fail, that’s where we can learn a ton from biomechanists, and then when you see low load activities where it’s more repeated, that’s where biomechanics becomes less important. I mean, that’s why it’s really frustrating to clinicians when you read the research, it keeps challenging your beliefs and you can always find something to support your belief. That’s one of the problems too, but it’s because biomechanics, at some point, isn’t that important, especially in the low load activities.
In terms of the habit, we see that a lot. The best research on that is the cognitive functional therapy research, where they kind of, see that the people who maybe it hurts when they extend their back, what they end up doing is sitting in a more extended posture. And then, if you look at their interventional studies, often what all they do is, they just change that posture for a little bit. The person desensitizes, and then they can go back to doing that posture in the future, once they’re not desensitized. So, you break the habit for a bit, they settle down, and then they’re fine, and it doesn’t matter what they do in the future.
KY: I hear a lot from patients that they have been told they have scoliosis, or a leg length discrepancy, and believe that, that’s the cause of their pain, and sometimes they may have been told this by another health care provider. What are your thoughts on structural abnormalities and their relationship with pain?
This is where we need to look at the research, and when you look at these things, like leg length and equality, scoliosis, anterior pelvic tilt, all of these findings are normal variations, they’re not linked. And we’ve had good evidence for decades now, that they’re not linked. The anterior pelvic tilt is always a funny one, because there’s papers from the early 90s and late 80s, showing that it’s a poor risk factor for pain, yet we still get caught up in these things. And it just makes no sense, because it’s such a pessimistic view of the body, that you have to be in this one ideal position, or a range of positions that fall into the ideal, rather than the fact that we’re incredibly adaptable and it’s not a big deal.
I always tell this story in my course, but the first person to deadlift five times their body weight, had a scoliosis like that. It’s like a massive curve, it’s just not that big of a deal, I don’t know why we get freaked out of those little pebbles. Don’t fear the pebbles.
KY: So, if the body is that adaptable and biomechanics or certain postures aren’t as important as many people believe, do you think that clinicians should abandon the traditional biomechanical model?
Yes and no. I mean, we shouldn’t abandon it, we should just reframe it. It still had its utility, so … and that’s where we can learn a lot from researchers too, is just figuring out how it’s useful. But, yeah, I think we still hold onto a lot of things that don’t have support. Maybe that’s part of our educational system, because it’s incredibly hard to change the training, I would think, at the level of a university. It would take a lot of people to decide to make those changes and then, because pain is so complicated, people have to agree on what we should be teaching, so it’s difficult. And then people still get clinical success using a traditional biomechanical model, and they maybe, think that, that explains the biomechanical model. And we have to be careful that just because we get results, doesn’t mean the model is correct. I think it’s interesting when there’s other explanations for why people get better. And if we can find what those explanations are, then maybe we can improve our treatments.
KY: What would you say is the non-biomechanical explanation for why posture can change pain?
Posture can still be linked with pain. Biomechanics is still important there. Again, you can have the habit. If it hurts to flex your back and you’re always sitting in flection, it’s not weird for changing your posture to help you out. The other non-biomechanical reason why posture can influence pain, could be expectation. Right? You set people up to think that sitting in a really arched position, or a flexed position, or sitting all day is going to cause pain, then it’s likely that that can sensitize them. We know that expectation has a huge influence on physiological functions, and certainly in pain, that’s why we have all this placebo research.
But the best example I can give is taste, right? So, we think that taste is just sensors on the tongue, and then it’s perceived as an apple. I’m eating an apple. Well, I always ask people, have you ever went to have a drink of something and it’s an opaque glass, and you think it’s orange juice, and you go up and you expect it to be orange juice, and you take a sip, and it’s not orange juice, it was really milk. That thing tastes disgusting. It doesn’t taste like orange juice, it doesn’t taste like milk, but it’s disgusting, because there’s a conflict with what you expected. Now, if it was just purely physiology, or purely sensors from the tongue, which would be an analog to nociception, then we would taste it as milk. Otherwise, it tastes disgusting. There’s the idea of the role of expectations.
So, if you set someone up to think that sitting in certain position or sitting too long, or having their head forward is going to cause pain, then you can actually increase their sensitivity, so it’s not really that weird. We set people up to fail, in a way.
KY: So, aside from patient expectation, if someone is in pain, then why does changing posture help reduce it?
Sometimes it doesn’t. That’s the problem. Sometimes it does if they’re always sitting in the same position and you change it, that’s a simple change in nociception and that can help. The other problem is, it doesn’t. You get people who are hypervigilant, and it can lead to more sensitivity. Yeah, otherwise we would be eliminating all neck pain in the office by going in there, and telling people how to sit, and getting them different chairs and changing the monitor height. So, we’ve tried these simple, postural interventions, and they just don’t seem to help. Maybe it’s the lack of movement that’s the bigger problem. It’s not like there’s one right way to sit.
I was in the military before, and it would hurt just standing at attention the whole time, or standing at ease. And technically, you’re in the ideal posture then. It doesn’t matter what posture you’re in, sometimes it’s going to hurt, and it feel better to do something else.
KY: What do you think are the biggest mistakes that clinicians make when educating patients about their pain?
I’ve never really thought about that. I can probably just say the biggest mistakes that I make, and most times, I think, I think they’re unintentional, and I think you can do this practicing in biomechanical model, or even in the psychosocial model, in that you say something that takes away their hope, or takes away their self efficacy. So, in the biomechanical world, it would be, you have pain because your hips are out of alignment, and you’re weak, and you have poorly stabilized core, and all these things, and people just think that they’re frail. But you can do the same thing with the psychosocial model.
You can start telling someone, “Oh, your pain is because of depression, and anxiety, and everything in your life can make you more painful.” So, you can screw people up just as much as using either model. Because you, kind of, complicate things, and you take away their ability to think that they have some control over it. Just speaking in generalities, it would be the idea that, that person loses self efficacy, and that they can’t do something to help themselves, and then they lose all hope and that just leads to the spiral of pain and disability. That would be the biggest one. And I’ve done all of those.
KY: So, if I was a patient, how would you educate me on why changing my posture can help to decrease my pain?
My big thing would be to say, “Not to worry about it.” That if you want to have different postures, go ahead. You can sit any way you like. I like to encourage people to think there’s nothing off limits. The certain movements might off limits for a bit, but in the future, you can end up tolerating everything, so I don’t want to make a big deal about posture, or anything, for that matter. Right, because then you start thinking that they need fixing. I know people can adapt to any posture they can get in, if they desensitize to it. So, I actually don’t make that big a deal about any posture. It’s just easier that way.
KY: Can you give us a patient success story?
My favorite success is when we make that shift of thinking, it’s not about fixing, it’s facilitating, and you just start doing the things that you want to be doing again. And you get rid of all the fear, and you get rid of all the barriers to physical activity. You get rid of all the barriers to resuming the things in your life that are important. Those are always the best success stories, where we just facilitate and give them the tools to solve their own problems. So, those are always my favorite success stores, where you end up making yourself redundant as a therapist, where no one’s relying on you, maybe initially, but after a while, there’s no reliance, or it’s a team approach, and ultimately, you’re really secondary.
KY: And what about a patient failure story?
Oh tons. What about a patient failure? A lot of what I try to do is, I like to change how people move sometimes, to help desensitize things, or I like to explain that pain is a lot more than just damage, and that a lot of factors can influence pain. But, I’ve had patients, where even after three visits, I haven’t communicated well, where they don’t believe me, or I’ve done it in such a way where they think that pain is all in their head, and they still need someone to fix … that it sounds like I’ve told them that pain is all in their head, which is wrong, it just means I didn’t do a good job of explaining.
And then, they just want to … well, they don’t normally tell you, but they just don’t come back. So, I’ve had patients where I’ve tried to communicate, and I just haven’t done a good job, kind of, how I’m answering that question.
KY: So, let’s jump into the topic of sports.
KY: So, although biomechanics may not correlate well with pain, there’s the counter argument that it can be important, when it comes to movement efficiency and sports performance. And I know a lot of strength and conditioning coaches teach and load specific movement patterns, so do you think that biomechanics become more important for high level performance?
So, do I think biomechanics are more important for performance? Yeah, probably. Biomechanics are more important there, but even there I would guess that there’s a huge degree of variability. And I can speak more with running, than anything else, where you see a lot of different ways that people move, and when you can get in to start tweaking what they should be doing, I don’t always agree with that. Where we think that we can … We know what the ideal way to move is, and that’s pretty tough with our research right now.
I would say, a rule of thumb would be, the heavier the load, the less options of movement you have, and that’s where things start looking the same, where people, kind of, have the same patterns of movement. So, that’s where the biomechanics might help, but the lower the loads, you can move a lot of different ways, and then the difficulty within all of that is, people are individuals, so the best way for them to solve that movement pattern … movement problem, which we would to get the most performance out of it, that they can, will be different for everybody.
And I think good coaches, who had more rely on than certainly myself here, recognized that normal variability, and the probably figure out the right tweaks to make for their individual athletes.
KY: Can you give some specific examples of high level athletes or sport movements that don’t follow that normal, efficient movement pattern?
If you look at high level runners, and I mean distance athletes, you will see that a number of them have, what people will consider, movement flaws. That would be knee valgus, over pronation, all of these things. Their arms, when they cross midline, when they’re running, because those things aren’t really flaws. We just called them flaws, and we don’t really have a reason to do that, so those are good examples.
One of the top female runners in the world, looks like her knees are going to slam together, and she has an egg beater when she runs. One of the top marathoners in the world, has a huge amount of pronation, so it looks like the inside of his ankles are hitting the ground. These are just normal patterns for them, and we freak out, and there’s no real reason to do that stuff. So, there’s lot of those exceptions. I mentioned that deadlifter who did five times his body weight with massive scoliosis. There’s a website for pro athletes with Scheuermann’s disease, which is like kyphosis. These are elite athletes with that.
If you look at the Paralympics, there would be incredible compensations, and changes in movement patterns. If those movement patterns were so horrible, then how do we even have the Paralympics? Right? The body’s pretty amazing and adaptable, so there’s a ton.
KY: And what are your thoughts on movement assessment screens?
It depends what they’re trying to assess. The FMS, and all of those, I guess they call them, screens, I think they’re good for checking those seven movements of how someone does that. Where it’s been tough for them is, making a promise of identifying injury risk factors, and it’s not their fault because injury’s that complicated. So, they seem to fall down when it comes to screening who’s at a higher risk, but they’re good, if they’re used more simply, like can you do a deep overhead squat? Well, sometimes that’s interesting, it’s a good screen for that, but maybe that’s less of a screen to find out who’s going to get injured. It’s relevant if you want someone … if someone’s doing the clean and jerk, or the snatch, then they should be able to probably do a deep overhead squat, with just a dowel. So, they’re good, if you simplify them, it’s when you try to make grander claims about injury reduction, and performance, that they, they, kind of, fall apart.
KY: Okay. And before we wrap up, would you like to tell us a little bit about the workbook that you’ve created?
So, I wrote a really simple pain workbook for patients mainly, and it was just set up to be … I mean, there’s 30 or 40 pages, I don’t even know, but it was really just set up so that they’re one page info graphics, with a simple key message. So, to me, a big key message for people in pain, is that, pain is an alarm, or pain is more about sensitivity, than damage on average, for the most part. And that’s really just set up so that people can get it for free. They can start shifting how they view pain, as not … it’s a problem in itself, but it’s, kind of, normal, and clinicians can use it because some of the concepts are … they challenge patients beliefs, so it’s hard to do that with their patients. So, sometimes it’s easier for someone else to break the bad news, and then you get to discuss it.
KY: And what are you involved in now, what does a typical day look like for you?
I’m a little skewed, I always wanted to have, sort of, three areas of activity, which was being a clinician, teaching, and research, and for the past 10 years, I’ve been too much of a clinician, and for the past year, I’ve been teaching too much. So, I’m trying to get back that balance. So, I’m actually gone, usually three weekends out of the month, so that’s a bit too much. I’m hoping to do less of that. And then, my typical day is I still see patients out of my house right now, during the middle of the week, but we’re trying to renovate to see … do that more often, and teach less, to get more balance. And then, hopefully, maybe, get back involved with more formal research.
KY: And how can people find out more about you?
I guess my website, greglehman.ca is the easiest, or Facebook, and all that, Twitter stuff.
KY: Thank you for listening to FUNCTIONAL F1RST podcast. If you’re enjoying this podcast, please give us a rating on the iTunes store, and stay tuned each month for a new episode.