Jared Powell:
Welcome to the shoulder physio podcast, a podcast dedicated to exploring meaningful topics in musculoskeletal healthcare. I'm your host, Jared Powell, before we begin, the primary purpose of this podcast is to educate and inform the views expressed in this podcast by myself and any guests are information only do not constitute professional advice and general in nature. If you act on the basis of any podcast episode, you should obtain specific advice from a qualified health professional before proceeding
Jared Powell:
Today's guest is Scott Morrison. Scott is a board certified physical therapist who specializes in high performance and sports medicine. He has experience working and consulting across elite sport and tactical communities. And currently he works within special operations. Scott serves as the chair of the a, a S P T performance enhancement and is pursuing a PhD under Franco Imari, a former guest on the show. I invited Scott on the podcast to talk about the offsite envelope of function paradigm introduced by Scott Die. In the 1990s. Scott is an expert communicator in this area, and I'm sure you'll get a lot from this episode. I certainly did just a quick heads up. My audio is poor during the conversation on reflection, I realized my microphone was back to front during the recording, a rookie era. I know, and I do apologize for this, and I swear to you, it will not happen in the future.
Jared Powell:
Luckily Scott's audio is nice and crisp before we get into the nitty gritty of the conversation and for your information for the first time in two years, I am running my one day shoulder workshop in near Melbourne in may and June, 2022. Tickets are limited to 30 participants for each event. The course offers a complete distillation of the evidence base for shoulder pain management, equipping you with up to date, knowledge, techniques, and clinical reasoning skills that are clinically actionable. If this is something you are interested in to show notes for more information, without any further delay, I bring to you my conversation with Scot Morrison.
Scot Morrison:
Thanks for having me, Jared. I don't know how special it is when you say that to every guest, right?
Jared Powell:
I know. I know. It's very true. Actually. I've gotta stop doing that. I've gotta be a little bit more once, once I've gotta criticize people from the get go. Yeah. so Scott, firstly, you have the exact same name as our prime minister here in Australia. So I wanna, I wanna just, I wanna just put that on record. Our prime minister is unpopular at the moment to say the least. So everybody listening in Australia do not tar this version of Scott Morrison with the same brush. You have anything to say to yourself, Scott, do you know much about our prime minister?
Scot Morrison:
Well, I've become very educated over the years because I get a lot of private messages and tweets and stuff across social media intended for your prime minister. The first thing I usually point out is that I spell my name correctly. He uses two Ts. So obviously there's some insecurities going on there, but yeah, no, I, I get multiple, especially anytime he does something, I find out all about it because I get a random collection of private messages and tweets telling me various things. So beyond the fact that he spells his name incorrectly yeah, not much, not much else in common. I think,
Jared Powell:
You know, on Australian politics,
Scot Morrison:
I'm not an expert on any politics. I don't think anyone really is so agreed.
Jared Powell:
People
Scot Morrison:
Just, was it Douglas Adams, I think said anyone capable of getting themselves elected by that fact is unqualified for the position that they get elected to. So I kinda go by that
Jared Powell:
Respect. I, I would, that, that is a, that's a very, that's a, that's a nice quote. Actually I might might integrate that into my, into my dinnertime politics talk. So we're gonna move away from politics, Scott, thankfully. And firstly, I just want you to introduce yourself to the audience. Most people will be familiar with, with you and your work, but just give us a snapshot into who youre, what you do and what a normal week looks like for you at the moment.
Scot Morrison:
Yeah. So background is well, undergrad was exercise science and then I told people I started off early two thousands, paying my bills through exercise, strength and conditioning, and then relatively rapidly realized I wasn't gonna pay my any bills with that. So ended up doing PT school. So finished up my doctorate in physical therapy couple years after undergrad. And since then have worked in a couple different areas, both sports as well as outpatient. More sports type clinics, interests are yeah, pretty much at exercise, prescription ex rehabilitation, processes, decision making around that. And my current work is within the tactical community. So that's what a daily life for me is getting to work with people who perform at, at a very high level with a slightly different risk and outcomes than my prior background in sports. So,
Jared Powell:
Yeah. Awesome. And that's, that's kinda why I like a lot of your stuff and I'm sure a lot of people do too, cause it's well rounded and it's human, like high performance and human performance is such an interesting topic. And I think it's it kind of gets lost a little bit now I think in on Twitter and like the, the nuanced discussions about high performance, it all just comes back to sort of one dimensional takes of performance. And in my opinion, most sight of the macro, the, and that's kind of why I've been drawn to some of your work in the past. So you don't, you don't have to respond to that, but that's something that, that I've been, that's sort of how you've come on my radar.
Scot Morrison:
Yeah, I, I would, yeah, I would agree that we lose sight, but then also I think sometimes the macro becomes excuse and cover all for not understanding some of the, the micro. So it's, you have to be able to zoom in and out and there has to be like your models have to scale, I think is really what it comes down to.
Jared Powell:
Well, we'll get into talk of the models a little bit later, but I wanna ask you, Scott, this is the most important question of today. What book you're reading right now and give me a TV show that you are, or movie I watch is over like four nights now. Cause I've got like a 35 minute attention span. So what book are you reading right now? Or what TV show are you watching?
Scot Morrison:
So answering what book is always impossible, cause I always have multiple books going, but I can tell you some of the ones that I'm currently enjoying. This one actually historical and foundations of measurement in the human sciences has been really fascinating. It's kind of a, both a educational textbook, but also a historical look at kind of where measurement has come from the history of measurement and kind of giving some perspective to the different approaches and models that we use. So that's been one of the books that I would say has been open more frequently than some of the others that maybe I should open more. And then for the contrast, if it's not that it's usually some science fiction or trash fantasy type, like I'll go down web novels where they're not even edited in just some random per somewhere wrote it and someone sent it to me and I'll sit there and read that. So it's a very kind of split between those as far as TV. It don't really watch that much, much like you, attention span is a little bit harder. But probably Rick and Morty is the current favorite. So
Jared Powell:
Nice. Yeah. I'm not, I can't convince my wife to watch Rick and Morty at this stage. So it has to be like an individual one. I don't don't have individual time at this point, but it has been on the it's recommended almost universally by my friends and colleagues. So yeah. Right. We'll get, we'll the nitty gritty the of, and today I wanna talk about the envelope of function and it's a term that it's probably been around for, let's say 20 years. So maybe a little bit more, let's say the mid nineties. And I'll get you to do a bit of a history on it, but I, I honestly hadn't heard of it until I, I think I heard Eric Mira talking about it, maybe I dunno, early 2010s or something like that. So it kind of was under the radar there for a little while for me. And I feel like I'm not, you know, I'm, I'm kind not behind too much when it comes to sports science and physiotherapy and, and all these kind of, of topics. So, and I do talk to a lot of students about it and it's certainly nothing that people are being taught at university still almost 20 years later. And it it's fascinating to me cause I think you'll, you'll support me in this assertion, possibly a controversial in that is a on ACU. So, so interpretation, what is what it
Scot Morrison:
That's a lot. I think it's like I've, I've seen a lot of different interpretations of it. I think the, if I remember correctly dive wrote about this, so Dr. Scott dye is the one who sort of proposed or formalized this. I'm not saying that it wasn't something discussed previously, but kind he's the one that formal. And if memory serves his first mention of it was prior to the physical stress theory paper, which is somewhat similar and you know bounces off. So the two are both, you know, reads that anybody should do. If you're in, if you work within something where you are applying stressors to a human and looking for adaptation over time, it's probably a, a good model to understand. I view it more as a model because like all models it's supposed, it's not supposed to explain everything, but it's supposed to orient you rapidly to key concepts.
Scot Morrison:
And that's kind of how I view it. It, I'm sure there's others who have taken it other ways. But yeah, so Dr. Scott, I wrote this up in the framework of patella Famor pain and basically what you have is a Y axis that is looking at the intensity and an X axis that's looking at duration or frequency. See, so I think in his classic one, it's like jumping out of a high two story window would be a one off event that would potentially be problematic for you or all the way. So that would be high and to the left on the chart, right along the Y axis and then maybe running a 50 mile or, or 50 kilometer type race, if you're not trained for that might be something that's pretty far out, low intensity each step, but much, much higher duration. And so what he did is drew a theoretical line that sort of Mo created, or sort of in captured that relationship between the two of those and the thought process is that that line can move up or down. So as your, this is, this is thinking more from a capacity perspective, right? So what your tissue what's
Jared Powell:
What's what's capacity. Yeah. Okay, good. So, yeah, let, let's, let's define these terms and, and I don't care about, I don't want an Oxford dictionary definition. I want your working operational definition of what you think capacity is and how that informs your practice.
Scot Morrison:
Yeah. So I typically teach this as a four quadrant capacity versus tolerance, and there's, there's a, a lot of overlap between the two, but yeah, just as an operational, something that works more of a colloquial Des definition, probably capacity is the limits structurally for the tissue or the system tolerance is how much of that limit you're willing to deal with. So if we think of this, as somebody who's dealing of tendonopathy capacity is probably much higher than tolerance, right? It's uncomfortable to run, but your likelihood of blowing out, let's say Achilles tendon is not necessarily, in fact it might be even lower, right, because you're offloading it a little bit that, so that would be an example of capacity versus tolerance. And then we can think of this as four quadrants, upper right hand quadrant, high acid, high tolerance cleared the train, push as hard as you want.
Scot Morrison:
Bottom left, hand quadrant, low capacity, low tolerance. This is usually more of your postoperative where it's gonna hurt, but it won't necessarily hurt before you also do damage. So think immediate postop type repair, anything that you're slinging, splinting, anything, adding extra protection, usually in that. And then the other two, who is, you can kind of think low capacity, high tolerant. This is somebody who a lot of times you can think of the runner who tells you that, you know, it started, it started being a problem after mile one and by 50 miles, I couldn't move anymore. And then they, you know, have a bone stress injury or something, right. They're somebody who's just able to push through or deal with it more or bottom right hand quadrant. We're now dealing with someone whose capacity is much higher, but their tolerance is low, whether it's their belief of what this is going to do to them, or just the pain associated with it being not necessarily represented by that capacity. So that's kind of how I view. I think it's hard to say one without the other, because there's a perception there's also locals, or, you know, goes down that whole rabbit hole, but that's my working definition for capacity and tolerance.
Jared Powell:
So we're saying, are we kind of, can I, can I say that capacity is more of an objective term and tolerance is more of a subjective interpretive individual to the patient or person kinda term, would you dichotomize it like that? Or is it more of a continuum?
Scot Morrison:
I don't know since, I mean, with most colloquial or most heuristics, they break down when you zoom in too far. So yeah, I would probably lean more towards a continuum cuz you can always point out examples where it's, well, this what's this
Jared Powell:
Sure.
Scot Morrison:
It's more, the idea behind this for me is to quickly orient yourself to the individual and it helps define and help you make best guesses when you start. So yeah. Think of it almost as tolerance is your, your ability to have an opinion on it. That might be a good way to think of it, right? If you have a bone stress injury, doesn't really matter what you think about it. We that's something objective. Now there's other things that maybe we can't image. So that's where it starts becoming a little theoretical. But yeah, the, the more likely it is that your opinion on it is playing a role. The more I would bump it into that tolerance with the understanding that this is just a general heuristic to kind of orient your thinking when you're approaching individuals.
Jared Powell:
Cool. So I assume, and we might come back to this in a minute, but I just wanna put it out there into the, just in case I forget it. So somebody can remind me, hopefully you that so would, would psychosocial variables or factors influence the tolerance of a tissue or whatever a person or would it influence the capacity or both or neither. I wanna come back to that. Alright. Because I don't, that's a question that we've got for later. I don't wanna totally derail your answer about the envelope. So I'll shelve that for a moment. Let's go back, let's put tolerance and capacity back into the envelope, but function and I'm sorry to interrupt you though.
Scot Morrison:
No, no, you're good. So I, again, this is kind of my interpretation having, you know, it's been, I forget when I first read about this but it's something that every time I revisited made more or sense and started bringing things together. But I, I think the envelope of function, as I understand it defined was this idea of a zone where the, you are above a dosage that is ineffective. So you you're at a dosage that's sufficient to maintain, but not quite hitting a dosage that will cause damage. And that's kind of that zone. So I, I find it beneficial if we're visualizing this as the place where it's okay for you to hang out with a lower likelihood, right? It's all probabilistic. We don't know. Right. It's, it's not fine lines that should all be drawn with a chalk held on the side.
Scot Morrison:
It just, these big thick lines. And then think of more of your bell shaped or your probabilistic type distribution. This is that big hump in the middle one standard deviation or whatever way, where it's most likely that if you're doing these things with this tolerance and, or I'm sorry with this dosage and this frequency that you're probably going to be okay, it's also probably enough to maintain whatever adaptations you have. So that, that's how I kind of conceptualize that that envelope idea with de training with injury or with in his case Patel Famor pain. And the, I think he takes more of a structural model. So let's say we're having some kind of issue going on with that kneecap, whether, and let's lump it together, whether it's tolerance or capacity, doesn't matter. We have a limitation in what we can do with that kneecap before we are stopped, that would be shifting that whole of spectrum or that area.
Scot Morrison:
If we think of it as just a drawing out what you can do, we're now limiting it. We've taken the kid. Who's allowed to ride his bike all around the neighborhood and told him he has to stay on the street. Right. Or, and then he keeps getting irritated. And now you can't go outside of your parent's eyesight right now. You gotta stay in the yard. That's that's that if we think of it as a narrative, it's a narrative of contraction. And then what we want, right. Is that narrative of expansion moving upward and outward. This is now okay. Yeah. You know, you're, you've shown yourself responsible or whatever. You can ride your bike outside. More, same idea with, as, as things adapt, as things calm down with, regardless of where that expansion is coming from, that would be shifting up and to the right. Now what we do typically as therapist is utilize exercise or some sort some form of stressor in order to drive that shift. Right? Cause what we're looking for is that hormetic dosage that is sufficient to drive adaptation, but not so much that we take from our recovery abilities or exacerbate the problem. And this is where I think hormesis really fits in well with this idea of, of that dosage and what we're looking for with it.
Jared Powell:
Okay, good. So adaptation, you mentioned a couple of times there, so we we're applying a physical stress. For example, let's say load, whatever that means as well. We'll stop we'll we won't define everything we say. Then our, our aim is to help the adapt somehow. Now, what, what do you mean by adapt? Do you mean build up structurally? Do you mean change? Do you mean strength? Do you mean heal? Do you mean like stop neurovascular infiltration for tendonopathy do you mean, are you talking molecular level cellular level? What do we mean by tissue adaptation here? And I assume the answer is gonna be all of the above and including the central nervous system. But tell me, tell me why.
Scot Morrison:
Yeah. Yeah. So the an yes, the answer is any, any adaptation that your body is capable of where I, I don't draw the line at, oh, this adaptation is good. This adaptation is bad. Or this is the adaptation that we do. We're I think the line should be drawn is our, our confidence, right? That this adaptation matters for the thing that we are addressing. And most of the time, our confidence is way higher than it should be. I think a good way to think of probability is that it is not something inherent to the situation. It is specific to our lack of knowledge. So probability is relative to how much or how little we know about the situation. The reason why we have to make a guess is cuz we're uncertain. If you flip a coin and it's flipped and I put it over and I'm holding it on my wrist and I say, heads or tails, your choice has nothing to do.
Scot Morrison:
There's no probabilistic aspect about what the coin is. You just are not aware of it. And that's most of, I think, where this stuff comes from. So all of those things. Sure. Yeah. Maybe it could be any of those. We're trying to drive adaptation in the things that we have the highest likelihood or highest probability of making a difference. But I would, I would tease that out and this is where that capacity for tolerance, I think adds to the framework because tolerance, if we're, if we're viewing, think of something like graded exposure, it's insufficient to probably drive adaptation in the things that we typically think of, right? Your five domains of fitness or whatever it is. But we do know that graded exposure can have some beneficial aspects for our, our ability to tolerate and hence the term tolerance. So this is where I'll look at the idea of minimum effective dose, maximum tolerated dose specific to the adaptation that you care about.
Scot Morrison:
So it may be that we have someone with very, very severe discomfort and you're just doing something like going through a Mo motion, right? You're just, you're just going, let's say we're doing a deadlift with just body weight. You're just doing a hinge pattern. And this is someone who five weeks ago was deadlifting 300 kilos, whatever, right? We're just making up a story here. It's unlikely that at that point they have detrained to the point where them doing the hinge pattern or practice is actually changing some sort of muscular hypertrophy or adaptation in the tendon or the bone or the ligament. So the minimum effective dosage for hypertrophy is probably not being met, but minimum effective dosage for some sort of decreased sensitization or for their ability to tolerate that movement that is being met. And so that's where tolerance versus capacity helps me to dial in on, all right, which 1:00 AM I trying to address?
Scot Morrison:
And then I know my entry point. If I'm trying to deal with tolerance, I don't need to hit some threshold that would drive hypertrophy cuz that's not my goal. And so that's where we, we make our best estimate of the thing that we think matters. And then we make our best estimate of the threshold of that minimum effective dosage. And we might start somewhere below that to ease into it, right. If we're trying to be extra cautious or we might start above it, if we think they can tolerate right. And we'll mess up and now, and then we we're like, oh, that was too much. Yeah. That's why we have feedback loops, right? If you're not being informed by the results, probably shouldn't be, taking these process, right? This is where I typically look at the ol loop within this of the idea of we observe orient decide act, right.
Scot Morrison:
And as we act, we need to observe because our actions drive things. So information is created by our actions. That information should allow us to reorient. And so now we have a better guess. Every time we do something, we have more information that increase in information should allow us to orient ourself to that envelope of function. So that's kind of how I view our clinical thought process around this envelope is we you're trying to decide what is my goal. I don't know if it's accurate or not, but it's my job to make a best guess. And then as I start taking a stab, stab at it, the feedback that's coming from it will help me know whether or not my estimation was a good one or yeah, maybe the probability starts dropping when we start seeing other outcomes come. So that makes sense. It's kind, there's a lot of different models.
Scot Morrison:
I don't think you could think of envelope of function just as this. All right. Now we're doing the envelope of function. There's John Boyd talks about. So he is the one who created the Ulu and he talks about, think of like a co board and you have sticky notes all over it. And each of those sticky notes is a model or a theory or something. None of them are fully act accurate. And we know that, but as new information comes in, we're trying to orient that new information too. All right. How does this fit in this model? All right. So if it's there, how does that reorient now my view of this situation and looking at the same construct with multiple angles helps us to try and a little better since none of them are actually that precise.
Jared Powell:
So it like Reverend bay has entered the chat. This sounds like a Basian approach. Scott, would that be, would that be fair to say, if we wanna put a label to it where you are, where you are making a guess based on incomplete information, which is what clinicians do all around the world every single day, you're making a guess you are doing something and then you modify, adapt change what you're doing in, in alignment with feedback or new information coming to you. So is this a Basian type approach?
Scot Morrison:
Yeah, I mean, I would think, I think the Basian idea just encapsulates an idea. That's fundamental to interacting with uncertainty, right? This is the same as perception, action, coupling on a field, you're moving up the field, the defender moves as he moves. You need to move in order to perceive, you need to perceive in order to move, as the defender moves, new affordances are created for you. As you start taking advantage of them, you are now changing the landscape and the defender will also move it's that constant Interac interaction, same thing with the conversation, same. This is just interacting within the independent agents results in a need for a feedback loop type system. And I think what the Baen idea really adds value to is helping us conceptualize that our knowledge is incomplete. This is not a matter of right wrong. This is not a dichotomy dichotomist type approach to it.
Scot Morrison:
It's a best guess by an understanding that it is a best guess. We freeing ourselves to update our probability. And I think that's where bay, you don't even need to know the formula, but the idea of what a Basian process is helps us to be better thinkers would be, yeah, I, so yes, bays, but also it's not this, oh, this is the one way it's I think it's so fundamental to how, like, this is how humans work within uncertainty and even without communication, it's everything we do when you have independent agents interacting, this is where emergence complexity, all that sort of stuff comes from. If you're an independent agent, you have the ability to affect things and even small, simple rules, like, you know, birds flying in flight or some and seeing those flock just transform. It's all just basic small rules, but they're independent. They can make a decision and their decision results in a change in the outcome, which then changes their decision. And that's how you get those really cool, big flock of birds fly.
Jared Powell:
Yeah. Yeah. No complexity and emergence and fascinating subjects. I've had a few people on the show talking about that stuff and I'm, I'm trying to get a few more people on actually from the Santa Fe Institute over a neck of the woods. And yeah, it could be interesting. I wanna talk about a bunch of D even in economics where complexity and all this sort of stuff is, is commonplace as well, but let's, let's stick to the human body where you and I are far more comfortable. I imagine. Just a note on Reverend bays actually, before we go too far, what a fascinating character, like just who, who just, you know, did mathematics in a spare time while whilst being a, a Reverend it's just those, those, those people a few hundred years ago, they seem like, I dunno, we just don't have them anymore. And I don't, or maybe that's just because we have a lot more, we've made a lot of discoveries. And there's not yeah. The
Scot Morrison:
Limits of
Jared Powell:
The limits
Scot Morrison:
Of knowledge. Yeah. And not, not that we, I mean, looking back some of the most brilliant people of all time. Absolutely. However, your ability to know to the limits of knowledge allowed you to have people who were creating massive discoveries in multiple domains, which is it's, I'm sure they would be very, very happy to live in today's world and have the advantage of not having to discover all the stuff that all of us do. So, yeah, it's a absolutely dude, dude was awesome. Applause. Like it's, it's a fascinating thing. There's a great book on the history of bays that I am blanking on the name right now, but I will get it out for you and you can put it in notes, but not only there, there is one about just be, but there's a, one of Bai in thinking that it'll come to me. We'll move on and come back to it. When I remember
Jared Powell:
getting old Scott that memory's going it's
Scot Morrison:
Newly fallacy, Bern, newly fallacy. That's
Jared Powell:
Fallacy.
Scot Morrison:
Yeah. Fallacy. Yes. Phenomenal. Oh, so much. Cool. Yeah.
Jared Powell:
It's bay is making a big comeback. Isn't he? With this old BA in inference when it's not, it's been around again for many, many centuries actually, but predictive processing, you go on Twitter and you can't, you can't really, you see these two camps, you see, paint is a perception. Paint is a sensation. One camp loves a predictive process in camp. One, one camp loves Cartesian interpretations of pain. Anyway, that's, that's again, a debate debate for debate for another day. So
Scot Morrison:
Another day
Jared Powell:
I wanna, I wanna move on. I just wanna ask a question actually, and this might be a simple answer. So is there a difference in you've alluded to it? Is there a difference between the envelope of function and all those physical stress theory or are they correlate parallel adjunctive?
Scot Morrison:
I, I think they're explaining similar ideas. I think the physical stress goes through a much, it goes much deeper into the process of the adapt that's occurring. So physical stress theory, you look at it as teeing up for mechanical transduction for a specific adaptation to impose demand for all of those things. Whereas the envelope of function, I think, is more of a global model that you, you can plug the physical stress theory into. And I think it's a little more elegant and it's simplicity, but if you combine the two kind of get you where you're trying to go, but it, it should be that as we go along and as we understand more we're building on this, right. So just because we had this model 20 years or whatever, go doesn't mean that we can't refine it right. As new information comes in. So as we start learning kinda like banished model, I think it, I, I see similarities between the two or we think fitness fatigue, right?
Scot Morrison:
Just the idea of these two things interacting together. What is fitness? What is fatigue? How does fatigue modify the fitness that you were capable of expressing at this time point, right? It, and then it's gone off and there's all sorts of other things that have come out of it. But fundamentally a lot of it comes down to this idea of dosage versus repetitions. And Brent Edwards has a phenomenal paper. I think it was 20 18, 20 19 that he had did with a few colleagues looking at just the increases in intensity versus the total repetitions to failure for various biological tissues. And you see mass, it's an exponential increase as you increase the intensity or the load, or basically stress and strain, right on the, on the area, the cycles that you can tolerates drop in an exponential manner. It's not a linear type thing.
Scot Morrison:
So as we started thinking of this, the top left hand side of this envelope function is probably a place where we need to be much more careful. We need to cycle through our feedback loop much more rapidly, cuz it's a lot easier to have a traumatic injury there than it is bottom right hand corner, just by function of the fact that we live in a temporal world, it takes you a while to accumulate all those repetitions. And usually you're starting like, oh, Hey, something's not feeling good. Right? You don't typically get catastrophic injuries in the bottom right hand side of the envelope function like you do in the top left hand. So, so high
Jared Powell:
Left being high load, low tolerance
Scot Morrison:
That so it would be thinking so in the terminology of the envelope of function, it would be high load, low repetition. So this is jumping out of the two story building. Gotcha. And I typically look at this as the benefit for clinicians from a reasoning process is identify where in this framework, the thing that you're trying to get back to goes, and if it's towards the left and high, you probably wanna take a much more gradual approach to it because you don't get many chances to do it right. As opposed. So someone getting back to skiing downhill or, or some the hygiene or something like that, that would be, you're gonna build up to it a little bit more, whereas maybe jogging, you can start jogging early return to running involves running right return to high jump might take you a little bit of other jumps before you're actually getting to that high jump.
Scot Morrison:
So think of this in that sense, return to, we do a long toss program to get back to pitching, but we don't necessarily do a, sometimes you can do a walk, but most return to run programs involve some kind of a shuffling run, right? When you start, there's sure you can do it most of the time, by the point, you know, if we're thinking our ACLS or something like that, they've walked a lot just as part of daily activities. So that's, that's kind of where I see the benefit of this is where is the activity you care about? And then it helps you orient and anchor your process and knowing how vigorous and how quickly you need to close those feedback loops in order to know if things are going wrong or not
Jared Powell:
Good. OK. So, so where does human psychology fit into the envelope of function? Does it, does it sit higher sort of order phenomena or is it tissue based or tissue obsessed? Where do psychological factors come into play
Scot Morrison:
Here? I don't. So my interpretation of this would be that psychological factors come into play in how they influence what you're doing, your willingness to do it, your tend see to do it right, all those sort of things, but a model's, you know, this is not the universal model that explains all things. And I think it starts breaking down when we try and force other things into it. So earlier you had asked that question about, well, you know, which is it a hundred percent, both probably right. Without psychological factors, there's probably no movement. There's probably no exploration of these things. But this model is not trying to explain it. Those are off to the left somewhere as you know, causal factors, but not specifically things we're assuming this model for me anyway, we've already determined that something physical is what we care about and that there is possibility for adaptation.
Scot Morrison:
So our goals are physical, right? We have whatever the case may be. We're trying to get the tendon to adapt. We're trying to increase strength. We're trying to bone stress injury is a great example of sure psychological factors are gonna play a huge role in all sorts of things. However, if we're just zooming in on can the bone tolerate return to running, that is a little bit more now, can the human tolerate running, I think is a different question. And that's when we zoom out, I don't know that the envelope of function gives us as much information on there and I'm, I'm perfectly okay with that. Right. I, I forget who it was that said the quote, but why isn't it enough to enjoy the, and I'm being a butcher this, but why is, why can't it be enough to enjoy the beauty of the flower garden without believing that fairies came along to create it, or, you know, something along that lines, like some, some of these curistics we know that there's limitations. We use them where they work and where they go crazy. And the other ends it's kinda like any statistical model. It, it explains right. That linear model explains the things within the spectrum. But if you go out, it starts getting crazy on both ends. Same idea here to me.
Jared Powell:
Yeah. Agree. I, I, but I do think it is important to know that what you are using is limited, you know, and not, not assume that we can extrapolate forever in a day. This is a perfect model. Everybody who comes into my practice will be somewhere within this envelope function and they might be, but the, the more we deal with the higher order phenomena in human existence, the, the mess it will be. And, and that's okay. It's not, I'm not trying to detract from the a function, but it's, it's very important to know the limitations of the model you're using
Scot Morrison:
A hundred percent. And that goes back to that idea of the cor board with the variety of models, because where one model does not work well, you should have other models that are picking up that aspect. And then what I'd ask you is if it doesn't fit onto envelope, a function, is that where we might be thinking of referring to someone else, right. Wh where does our domain stop? Right? The same exactly. Like models, don't explain everything. Our profession does not treat right. There are other professions that do a much better job at a lot of things that we don't. So I think, yes, we need to know the limitations of our model. We also need to know the limitations of what we do. You, you are bad best at your craft when you don't do the things that you're not good at. Like, I always tell people just because you've seen someone else do a bad job doesn't mean you need to do a bad job at it, too, right? Yeah. You go to your mechanic and he tells you, oh yeah, don't get this person to fix your AC at your house. He doesn't say, I'll come over and do it for you. He says, let me refer you guy, who does a great job, or this woman who will do a really good job at that. And that's, I guess for me, the, the, the corollary to that, yes. Know the limitations of your model, but also know your limitations.
Jared Powell:
Yeah. That's a good point. So if you are, if you are thinking that this particular patient evades the envelope of function, then possibly that patients know right. To be seen by a physiotherapist, at least primarily in terms of treating the pain presentation or injury presentation or whatever it might be. So that's, that's a really good point. And, and I'll just come back too. So even though, even though there might be some psychological variables at play, even if you just implement an intervention to try and cause some tissue adaptation, for example, and indirectly, you're probably going to be affecting other psychological variables as well. And this is when we start talking about causal mechanisms and what's actually changing what a new Institute and intervention, just because we give resistance exercise to a particular person with a particular pain presentation doesn't mean that the causal mechanisms underpinning that person's recovery is just due to tissue changes. So you can have a unidimensional intervention, resistance exercise, and that has this plethora of causal mechanisms underpin
Scot Morrison:
Absolutely. With the caveat that, you know, if, if we're doing it to target things that are not within our domain, probably a good time to pull in someone else that does it. So if you have a patient who you're like, well, I don't know that this is gonna be that helpful, but let's do it anyway. Hey, you know, maybe talk to like, that's usually where saying, Hey, have you considered talking to the psychologist or something like that, going back to that, talk about likelihood of probability. That is a patient where I am saying the likelihood of changes in tissue being relevant to the thing that you come in and complain to me about or told me about today is relatively low. And the that's when it comes to informed consent. That's what we're talking about is, listen, I'm not sure that this is beneficial. I can tell you that doing these things will result in changes here because that's just how biology tends to work.
Scot Morrison:
I'm confident. Yes. Yes. I'm relatively confident that I'm good at that aspect, but I don't know if it actually really matters for the thing that you care about. So you tell me, do you wanna, you know, you want to give it, and that's where I'm waiting that likelihood of my intervention, I'm much more confident with a broken bone or postop that what I'm doing matters for that than someone who comes in with, you know, chronic history of pain or, or whatever else it may be. So just because the intervention does a lot of things doesn't mean that you are appropriate to try and target those things that it does. This goes to the exercise question of very I'm a personal trainer and I'm using a squat or I'm a therapist and I'm using a squat. You're both using the same movement, but your intentions, your goals, your plans are very based off of your scope, your expertise, your knowledge.
Scot Morrison:
So yeah, you're doing the same movement. You may even be getting hypertrophy with both of 'em as the goal, but there's a different reason why you're pursuing that. And so I think just some clarity and nuance in there's a lot of great things that happen when you exercise is probably a good idea does not mean that it makes us a psychologist, right? Because there's some good, higher order constructs that come from that. There's great research showing depression is probably affected by exercise. I don't prescribe exercise for depression. That's not what I do. Just like a personal trainer doesn't necessarily prescribe exercise to heal or to address injuries, something like that. Right.
Jared Powell:
Good. Absolutely. Good scope got very, so wanna ask, been to scientific inquiry, scientific investigation I'm and a huge part of Papa's work is if, if a theory isn't able to be tested, it's not scientific. And I don't believe that applies to the letter of the law. There's huge criticisms on that in the field of philosophy of science, but I just want your opinion on that, or is it just a used to way of looking at clinical practice and then you to testing within the, the theory itself? So I'll, I'll hand that over to you. Complicated question.
Scot Morrison:
Yeah. I mean, I, I tend to see Popper's falsification idea as probably beneficial at the time, but hopefully not. I, I, you know, every, everyone in science knows popper and that's the extent of the philosophy of science that really goes through. So, you know, falsification sure. The demarcation program and that these are all big things, but go bays popper to me is much more like a, a no hypothesis type test of yes, no. And then if it's no, we go right back to the beginning and start all over again. Bays would say that as we get information, we get better at our initial guess. And so that, that's where I, and that's a whole other conversation, but I do, I do take a little bit of issue with, if you can't falsify it, that means it's useless. What I think a model like this does is it allows us to make predictions which can be tested, but this model tends to have emerged from just, or underlying biological, like specific adaptation to impose demand.
Scot Morrison:
Right. We, we know this is a relatively bedrock type thing of any sort again, hor is that idea of a dosage that creates positive adaptation of a stressor that would be toxic at higher dosage. Right? So you get that hormetic curve. That's really what to me this is doing is it's just creating a framework for the things that we have looked at in isolation. I don't, I don't know how you would like test this, right. I, I, you know, from a thought experience, jump off of a five story building once or go run a hundred miles. Both of them will probably lead to an so at the extremes, we, we get there now where it goes from the extreme to, again, it's a model it's not supposed to be clear. Right. maybe it is fuzzy as, as, so we zoom in at the, like the joke.
Scot Morrison:
I don't know if you're familiar with the Yeti or the right. The big foot here. All of the, yes, yes, yes. All. Yeah. So all of the picture are fuzzy and Mitch Headberg the comedian. He had a great joke that he said, what if, what if Bigfoot is fuzzy, right? The problem isn't that photographers, aren't taking a good picture. It's that he is fuzzy. And I, I think of these models as these model, it's not that our cameras or our pictures are bad of it it's that these models are fuzzy. And if you keep zooming in, it'll keep getting fuzzier because it's not supposed to get us that clarity in that thing. If we're trying to get that specific, we need to have a much more specific hypothesis, a much more specific statement, which this envelope of function can help us start with, but would not be the place that we tested. That's that's my opinion on it. Yeah. I was always happy to get a Mitch quote in
Jared Powell:
you're doing well with the quotes actually. I think, yeah. You're, you've had at least three Scott, so you're doing well. You, you, the record is five. I believe so. Yeah. You you're nearly there. Oh,
Scot Morrison:
I can no original thoughts here. Right? None. It's
Jared Powell:
Nothing new under the science God. Yeah. So going back to pop, like, I mean, you're right. Like there are, the science of consciousness is technically untestable at this point. Even the science of pain is untestable cause that is a subjective experience. And there, there are aspects within quantum mechanics, many worlds interpretation. Quantum mechanics is untestable at this point in time, as far as I'm aware, I think we're only have access to one universe. So there is a, so it does break down and it can break down. But I think it is a nice, the demarcation principle is a, a really good way of orienting yourself to some theory that you hear and that's, or that have some that might have some validity or that might help in some respects. It is a good way of spotting, in my opinion.
Scot Morrison:
It's yeah. It's a, it's a very good way of spotting things that you should not be very confident about. Right. If it's untestable then, you know, just like with everything else, the Higgs Boso was amazing because of the fact that we found something that had been predicted by a theory for a while. Now, if we had not found it, we don't immediately discard the theory. It may just be that we still aren't at the place where we can ask that question. But our confidence, this is where bay comes back in. Our confidence will go up and down based off of it, as opposed to we don't just to use the nomenclature of our time. We don't just that idea out there and start with a whole new one. Right. We're now. All right. Hey, you know what? Let's, this has explained a lot of things.
Scot Morrison:
It did not explain this what's going on here half the time. It's us messing up the testing, right? Mm-Hmm when, when, when the lab, I forget which one it was got found faster than like travel their first thing wasn't saying, Hey, all of these theories about light being the limit of speed in our universe is wrong. No, it was, can you check our, we, we think we did something wrong, right? And I think that's where this idea is. It's not falsification is a good idea, but sometimes the people who are trying to falsify it are more, it just keeps going down. Right? It's all the exactly.
Jared Powell:
And I think
Scot Morrison:
What
Jared Powell:
We're doing, I think, I think, I think Papa does accept that. And, and then Lato has improved upon Papa. And Thomas co says something similar and then fire as well, where, well, if something's wrong or something has been falsified or the test doesn't match the prediction, where could it have gone wrong? And then you look at the experiment, then you look at the scientists evolve. And if it's repeatedly falsified, cause nothing's really falsified after one experiment and most people accept this. And this is the whole point of Koons paradigm where you kind of, you're still just a working scientist that, that prediction, or that, that tested, it match that prediction. What happened, let's go back and if it keeps happening, and this is why I am confident speaking definitively about the concept of shoulder impingement and perhaps why we should abandoned it. But we've got so much data now that really leaves that diagnosis is it's you can't in good faith. Give that diagnosis in my opinion. So once, once every, and start accumulating to that extent repeatedly mm-hmm, across labs across countries, across people. Then you have to look at it,
Scot Morrison:
But we're still not at a probability of one. We might be 0.99
Jared Powell:
Will, will we ever? Yep, exactly.
Scot Morrison:
Yeah, exactly. And that's again, go, you know, everything is probabilistic. No, we will never, we should, should never be one. And that's the, the big problem with a lot of this stuff is this instead of Isaac osoff's paper about being less wrong, a lot of times, I think we're just wrong differently. So we're just as confident about another theory that has plenty of flaws. And it only explained the one thing that we became aware of might not be right. And now we've climbed a new hill. That's just in the same vicinity as the old hill, we planted a new flag and now we're ready to go through the same old process all over again. Whereas what we should be doing is increasing and decreasing our confidence in a variety of things and just being better at understanding what we don't know and still treating the patient with the understanding that most of what we do is hypothetical. And you know, it's a lot of times I had a patient one who came in and had urges back after falling and saw him next time I see him. He's like, oh, I'm all better. I'm like, yeah, I nailed that. He's like, no, actually on my way home from the last one, I tripped and fell at the same spot that I did before I landed, stood up. My back was all better. Great. That's awesome. I mean, all right. That's clinical practice. Sometimes you just smile a truck
Jared Powell:
I'm with you. I've got, I've got inable instances of the exact same, but you've just gotta, you've gotta be OK with that. You've gotta be, you've gotta be comfortable in the gray, comfortable with uncertainty. Don't you and youre. It's all, it's all, it's all some sort of dance with probabilities and confidence. And as long as you're doing things that are like biologically plausible and not harmful.
Scot Morrison:
Yep. And you have feedback that actually is telling you about what's going on. The worst thing that can happen is seeing the world as you believe it exists and set of how it does. I, and I don't know who said this quote either, but the it's, and it's not the things that, you know it's not the things you don't know that get you, it's the things, you know, for sure that just ain't. So that's the, the worst problem is when we think we know that's
Jared Powell:
Twain, it's not Twain
Scot Morrison:
Twain. I, I believe that it was attributed to Twain, but then it wasn't him actually. And I don't remember who they say actually said it first. So that's why I'm saying, I, I don't remember who said it, but the analogy I use is the idea of going into a, your bedroom, the lights off, lived there for a while. You know, where things are, you walk in confidently and move around the room. What you didn't know is that your partner rearranged the furniture before you went in your confidence was very high that you knew what was going on. The reality was things change. Now, if before you went into the room, your partner, your partner said, Hey, I rearranged the furniture. You have no difference in actual knowledge of where things are, but you approach it very differently. It, it goes from a act react type thing, right?
Scot Morrison:
So if we think of the Canne framework of the four different domains of how we approach different situations, we go from that sort of, we, this standard process, we go in, we turn left after three steps, right? And then all of a sudden, boom, you run into something. What we do is we approach the room with the idea of we probe and then we change. And then we act right. And that's, that's the fundamental, I think difference to all of this is if we have models that are helping us to make decisions. And if we are very, very clear on what our feedback is actually telling us, cuz this is where applied kinesiology, all these things that tell us the thing that we wanna see. Well, if your test isn't actually standing on a scale, you believe you're measuring your weight. But if you wearing all your clothes and you have a backpack on the scale is telling you how much mass is on it.
Scot Morrison:
It's not telling you how much you weigh. And if this is why someone can sneak their toe in behind you and touch the scale and you think, oh, I gained five pounds or two kilos or whatever, you know, your unit measures. That's because we think we're measuring our weight. When we stand on the scale, the scale is measuring the amount of force, right? The amount of mass placed on it with this constant of gravity. That's the problem we face in the clinic is we believe that what we're doing is measuring the thing, but what we're actually measuring. So dynamometry being a classic example of you think you're measuring the extension to what you're actually measuring is how much force it takes to push you over or how much force it takes to lift their butt up off of the plinth or how much tolerance the, they have two pain pressure at that. There's so many other things that can be the limb fact on this. That's the issue is be aware. And just as much as we have to be uncertain about the bigger things, we also need to be uncertain about the feedback that we are basing our updated perceptions on. So that's my rant.
Jared Powell:
It's a beautiful rant, Scott. I think honestly, I think that's a, a very nice place to wrap up. We've had a enjoyable engaging meandering conversation for four quotes, maybe in the end, Scott. So you pull in one short to go back and
Scot Morrison:
I think there's more than that. I'm gonna hold myself too that if not, I'll just say the Sauber take like Sauber , which is another quote. So there we go. Five. Good.
Jared Powell:
I love it. It's been, it's been really good fun. I've been wanting to chat for you for a long time. We've had this in the books for a bit. But we've finally, we've finally made it happens. So thank you very much for coming on. Where can everybody find you, Scott? Where are you active on the socials and what's your website?
Scot Morrison:
Yeah, so the website is physio practice.co and the Twitter is at S C OT, M O R R S N. Twitter is really where I do most a action as just me. Instagram is more of like, I have physio practice. So it's physio unders practice on Instagram and that's more information stuff. So my website also has just a ton of like free information that I put up there and curate, if you are a U S P T I have to give a for the sports academy. So I'm the chair of the sports performance, special interest group. And we do a ton of stuff on there. So I'm also on there a lot, but that is more within the us
Jared Powell:
And you, and you have a course slot them all loading, correct?
Scot Morrison:
I do. Yes. slot them all loading it's fromt use the term lop optimal, and I loved it. Right. Exercise, prescription horseshoe and hand grenades or three things we're close enough is good and you don't need to be right.
Jared Powell:
And I've heard many, many good things about your course Scott. So do you kind of cover similar things within your not similar things, obviously? Would you tell me what you cover in your course? Vaguely. Sorry to put on the spot.
Scot Morrison:
Yeah, no, no, no problem. Like some of the ideas of tolerance first capacity, I do teach this based off of the envelope of function, but optimal being the idea of exercise prescription is based off of making a best guess interacting and then seeing what happens. And really the course is more about critical thinking. It is a higher order course. I do get students who come and enjoy it. Typically a lot more work for students or new grads and the ones who have come are ones who are really investing in putting time in it. But yeah, it's, it's the course that I find enjoyable to teach. So definitely requires a lot of thinking on my part as well as everyone involved. It's a lot of question and answer. So I, I teach it currently online as well. So I, I post up whenever stuff comes, but yeah, so the idea is optimal, it's it doesn't have to be optimal.
Scot Morrison:
Right. We have the whole idea of optimal loading, but if you, once you're good enough, you're wasting time if you're not doing something. So that's really just the process of thinking. And then in exercise, prescription framework around that testing and goal setting and kind of that process of how, how do we get from here to there in a way that doesn't overwhelm our thought process, right? That doesn't just paralyze us when we have 15 patients in the next three hours and have to do something with each one. So a lot mores and stuff like that.
Jared Powell:
I love if like our discussion today. I highly recommending out evening over there in Florida.
Scot Morrison:
Yeah. I think it's like 9, 9 40, but bedtime is like, whenever I can't continue doing things. And then I hate myself in the morning.
Jared Powell:
that's you don't have kids yet. I've got a, I've got a little baby. No,
Scot Morrison:
Yeah. I slide
Jared Powell:
Into bed.
Scot Morrison:
Oh yeah. No, I, I, no kids. So
Jared Powell:
You, anyway, we have conversation.
Scot Morrison:
Scott, take
Jared Powell:
Question yourself, my friend. All right, mate. That's you, you too. Thank you for listening to this episode of the shoulder physio podcast. It's Scott Morrison. If you want more information about today's episode, check out our show notes at www dot shoulder, physio.com. If you liked what you heard today, don't forget to follow and subscribe on your podcast player of choice and leave a rating or review. It really helps the show reach more people. Thanks for listening. I'll chat to you soon.
