Last month, I posted an audio interview with Dr. Stu McGill HERE. At that time, many readers requested a written transcription of the interview. Well, ask, and you shall receive! By the way, my favorite quote is this:

And what the listeners – I hope they understand – is that it doesn’t matter whether I’m with you (Bret) or Pavel or Dan John or back in the old days of Mel Siff, Zatsiorsky and Gracovetsky, any of these people, we were all good friends. We enjoyed one another. We enjoyed debating. And it was over a beer and peanuts. We knew one another’s kids, all of these things. They came and stayed at houses just like you did. You know, staying at Mel’s house. Wonderful time! It’s the disciples that are ready to kill someone who would dare challenge who they perceived as being a leader or a guru. I wish all that would go away. Georges St. Pierre, who you know I’m quite a fan of – he’s just an outstanding individual. He has a quote. Something about, “I honor my opponents because they define me. Without my opponents I’m nothing.” – Stu McGill

Below is the entire interview.

An Interview With Dr. Stu McGill

Bret: Hello. Welcome. This is a very anticipated interview here. I’ve got Doctor Stu McGill on the call and I’m very excited to interview him. I posted a blog last week sometime, I believe (maybe Wednesday) and I asked people if they wanted to know more about these topics. There was an overwhelming response from people saying, “Please interview Stu.” They wanted to hear what he has to say so just to set the stage, I went out there to Waterloo, Canada and spent the day with Doctor McGill. We had a lot of great conversations and we did some really nice experiments at his laboratory. Without further ado, Stu why don’t you tell the listeners a little about who you are.Stu

Stu McGill: Who I am. Hi Bret, first of all. I’m a professor of spine biomechanics, at least that’s my official title. How about that?

Bret: How many years have you been studying the spine?

Stu McGill: I don’t know. Over 30.

Bret: Over 30 years of studying the spine. Since you’re gonna be humble here, I would say Stu is regarded as the world’s leading spinal bio-mechanist. You see some guys in the literature that might have advanced knowledge of the spine, like with modeling or with the physics of it but they don’t understand the practical aspects of strength and conditioning and physical therapy. That requires an equal study of the science, mathematics, and the physics. So, that’s what makes Doctor McGill special. I decided I’m just gonna roll through the questions that I have listed on my blog, because we talked about a lot of interesting things. So first off Stu, please tell the listeners, in college what did you think you were gonna do and how did you discover your love of physics?

Stu McGill: Well I’m glad you’re leading this Bret because I can’t remember what we talked about. I appreciate this.

Bret:: Are really you surprised by how much of it I remembered?

Stu McGill: I’d have to say that. I never saw you take one note. Yet, you seem to recall all of these serial topics. Nonetheless, what I thought I was going to do in university – I hadn’t a clue. This will be a fun story for you. Have you heard of this website: RateMyProfessor.com.

Bret: Yes

Stu McGill: At our program at the university, I’m the first professor that the students see out of high school at our program and I also happen to be the last. I sort of bookend the program. A student was in my first lecture, straight out of high school, September the 9th, maybe it was the 13th, I can’t remember. There was a new entry on rate my professor, this kid straight out of high school and rated me with one lecture and no other context, other than the high school experience. Apparently, I suck. There you go. But what I did say in that first lecture was that look, when I was in university, I had not a clue what I was going to end up doing and it was just a bit of fate and a bit of karma. I was sitting in math class and I could not do math or physics to save my life in high school. And this professor came in and said, “Look, you don’t need to understand limits to understand calculus.” That’s where they started us in high school and I was totally lost. He said, “You know it’s basically how one variable changes as a function of another.” You know, distance and time or mass and something else. All of a sudden, I could feel all of these relationships in my hand. So these were magical quantum events for me where I suddenly understand the magic of math and physics and could feel it in my hands. And I mean as you know, we did talk.

Looking at my body now, it’s shameful. I did, at that time, train fairly heavily. I was interested in sports performance for myself, of course, but I slowly became more interested in physics. Would you like me just to finish up that library story?

Bret: Sure

Stu McGill: I must have been lost one day but I found myself at the university library and there was a book on Biomechanics and I picked it up and started to thumb through it and thought – Wow! This is a terrific fusion between anatomy (because I had been taking the medical anatomy courses) and I quite enjoyed that and physics. So I applied for biomechanics at the University of Ottawa and did my Masters there.

Bret: Before you finished off you degree, did you assume that you were gonna be a carpenter, a plumber or something like that?

Stu McGill: Coming out of high school, I thought I was gonna be a plumber. Yeah, that’s true.

Bret: So then you realized that you have a knack and a affinity for physics but at this point in time you had no clue that you were gonna go study the spine. Correct?

Stu McGill: That’s correct. I went to university with no real interest other than football. As it turned out, I was not a very good university footballer. As you’ll recall (towards the end of my undergraduate career) I got into road cycling. I wanted to go to university of Ottawa so I could ride my bike up in the French Gatineau Hills in Quebec. For my PHD…

Bret: Before you get into your PHD, basically your father fell sick and you needed to move home to be with him.

Stu McGill: That is correct, yeah.

Bret: Then you moved back to Waterloo. But at this point in time, you met your future PHD supervisor, correct?

Stu McGill: Well it’s sort of like that. My parents didn’t live in Waterloo. they were outside. But I did come home to give my mother a hand. My father was in a wheelchair by this time. So I applied to the University of Waterloo for systems engineering and I was gonna work with a professor there who was interested in injury prevention.

Then I was playing hockey for the professor’s team at the University of Ottawa while I was going my masters and we happened to play the University of Waterloo. And there was a professor there named Bob Norman who played for Waterloo. He was quite a hockey player when he was an undergraduate as well. In any case, we started to talk to make the long story short he did become my actual PHD supervisor.

At that game, he invited me back to his place and said “come to Waterloo and visit. By the way, you can process some of your data in my laboratory; because I was having a devil of a time. Computers weren’t even invented yet. I had taken films of people doing movements. I was digitizing old movie film on a piece of graph paper and writing down the XY coordinates, believe it or not. Bob had a machine that would play the film and it would electronically obtain the XY coordinates.

So anyway, he was very kind and he invited me down to stay at his house. I did and finished off my masters and then switched my direction. He was just starting spine work so together we started to work on the spine as a PHD student. That was the story of how all that came. But you see, I think the moral of the story is that it was really just dumb luck. Meeting the right people at the right time – some good people and just progressing.

Bret: Well, we see that a lot (probably in every industry) but in the field of strength and conditioning that there are a lot of coaches who just stumbled into strength coaching and ended up in it. A lot of these people would have been good at whatever they chose to do just because they have passion and talent.

I expect the same would be true for you.

So moving on to the early work with Norman, I’ve gone back and read a lot of your original papers from the early 90’s, maybe some from the 80s. Some of your work with Norman seems like you two were out busting bro-science. You guys were busting myths and misconceptions. I always got the impression that this was indeed your supervisor and he was kind of thrilled by your enthusiasm to go break down these doors.

I don’t know if that’s true or not but I know that there were a lot of things that spinal researchers were saying that weren’t exactly on the right path. I’ve also read a lot of papers by spinal researchers at that time. For example, Serge Gracovetsky, who is a very popular spinal researcher. It’s funny because having read enough of your stuff over the years, I can read some of Serge’s stuff and go, Okay. That’s not accurate… That’s not accurate. In fact, I’ve read a couple of legendary papers by Gracovetsky including The Spinal Engine (HERE), where he basically talks about how the spine drives gate and the spine is responsible for basically, powering the walking mechanism. Also, a paper called The Optimum Spine (click HERE) which is like this 55 page document, and pretty much piece by piece, you can take everything he wrote and kind of pick it apart- as you’ve written papers saying otherwise. So when I spoke to you last month I brought that up. You guys used to butt heads a lot. Correct?

Stu McGill: Yeah, those were, not a time that was stressful but looking back now it was a lot of fun. I’ll attribute much of my forging to some of those battles (if you will). Here’s how that evolved. My PHD supervisor was a very astute, political fellow. He understood what drove science. How political and social forces drive science. He was interested in questions like What’s the number? What would a lawyer use to say this is a risky load on the body? One of the first projects that assigned me was to use some of the simple spine models of the day to come up with some of these numbers. Because he was being asked to be an expert witness in legal cases where the court wanted to know, was this a dangerous load or not and the lawyers needed a number. I would program some of these simple models with basically a gym crane and then a single equivalent muscle representing the whole extensor complex. You and I both know that’s not anatomically accurate. It doesn’t capture the contraction of the abdominals and intra-abdominal pressure, in the individual ways that good movers perform a task and that a poor mover might use at task. This wasn’t good enough for me. So I went back to Bob and said, “I don’t believe these models. I think what I would like to do is create…”

Bret: Stu. Let me clarify that real quickly. Essentially they would take – correct me if I’m wrong – The common process back then was to take the average of the moment arms of the thoracic extensors and just estimate them and generalize them to be, like say five millimeters or something like that, or whatever.

Stu McGill: Exactly. The distance was a five centimeter moment arm.

Bret: 5 centimeter moment arm. You’ve found that was not correct and that led to an overestimation. Also, your PHD model you made is much more complex. You basically looked at every single muscle, tendon, and all the ligaments – basically every component that contributes to forces on the spine. Correct?

Stu McGill: Exactly. See I wasn’t a political back in those days. I was the guy who wanted to know why was the sixty-two year old lady getting injured lifting boxes at the post office and a twenty-two year old wasn’t. We sort of know why, the tissues were weaker. But was she doing other things that, perhaps, loaded the tissues closer to tolerance.

Then we realized that with this entire spectrum of biological variability, you can’t come up with single numbers. This is politics that lawyers want these numbers. We’re going to get into some controversies that are later in my career.

Getting back to these spinal engine and these theories of Doctor Gracovetsky, he was a brilliant engineer and very persuasive speaker. He came up with his colleague, Harry Farfan at the time, who was a spine surgeon who had theories on how the spine worked. He would say things like, “Well, the muscles of the spine are not strong enough.” Now let’s look at this power lifter picking up 400 Kilos from the floor. There’s no way the spine muscles are large enough. Therefore, there must be mechanisms that we do not understand or are in current models. So he came up with the lumbodorsal fascia theory where the fascia gets stretched behind the muscles and takes some of the load. And increases the mechanical advantage of the extensors and this sort of thing.

But when I went at it with my model, I in those days had something like 96 lips of muscle. Everything that crossed the low back and if you take an MRI slice through the lumbar spine, you will see the lumbar musculature cutting cross-section and you’ll measure its size. What you don’t realize is there are muscles all the way up the back that also contribute to that force. But when they are at the lumbar level through the layer of the skin, they’re just a little tendon so you can’t see the muscle. So the fact that his models were ignoring all of this musculature, the latisimmus dorsi, big lat muscles working through the fascia, I didn’t think it was anatomically accurate. If you just captured the anatomy correctly, you didn’t need these very esoteric explanations about how the back was. In fact, it became quite simplified. Then his ideas on when we walk, we move the hips.

Bret: Stu before we get into this spinal engine let me elaborate on that. I actually embedded a video in my blog two years ago because it was a video of Gracovetsky talking about the first facial congress (link is here: https://www.youtube.com/watch?v=B-SMUA3QfVw&list=PL5DC2627D5F32C664&index=1) and he brought that up, and he’s a wonderful speaker and made a joke and the whole audience erupted in laughter. This just goes to show you just how little people know about biomechanics and spinal biomechanics because you could tell them anything and they will believe it. he said that if you look at what the muscles are capable of doing, it is a very small amount. So the lumbar fascia has to be contributing to stabilizing the back. But correct me if I’m wrong, wasn’t he using a smaller moment arm and also the physiological cross sectional area of ordinary people and not power lifters. Correct?

Stu McGill: I don’t even think he captured ordinary people with enough ability for my satisfaction.

Bret: They were elderly cadavers or something.

Stu McGill: I can’t recall exactly where the data came from but again, if you look at the whole spine and capture it, the statement that the muscles are not strong enough is patently wrong.

Bret: You’ve talked about how the thoracic extensors are great stabilizers of the lumbar spine because of their longer moment arms.

Stu McGill: If we get into a study or a conversation on stability, do you wanna spend three or four minutes on that?

Bret: No. Let’s get into that later. So essentially, a lot of this stuff he was talking about at the time. One-by-one you would kind of pick it off. Just talk about the spinal engine real quick. I remember reading that and it just doesn’t make sense. Like you said, it’s very esoteric and elusive. I will tell you that people in our industry are drawn to this. He talked about how if you take a metal rod and you bend it and then twisted and side bend it, it will create rotational torque. That’s what drives gait. What are the problems with that?

Stu McGill: Well the problem is that it’s true for a rod made of fiberglass or graphite or something like that. So let’s replicate the motions that he’s showing in his graphite rod in a real person. What you have to do is walk while swinging your hips, rolling each hip over. Well when you measure people there are some people who have totally the opposite pattern in their hips. In other words, their spinal engine is in reverse. Yet, they’re still able to walk forward. I remember being at a spine meeting one time and Gunnar Andersson, who is a very well known spine surgeon and scientist out of Chicago. He stood up and said, Yes, but this patient right over here. They’ve had a fusion from L1 down to the sacrum. Their spine is stuck in neutral and cannot move. Does that mean they can’t walk?” The fact that the room erupted in laughter the other way. The point is that you have big leg muscles for a reason and that’s how you walk.

Bret: The hips are the engine in most situations, huh?

Stu McGill: Thank you. I thought you might appreciate that.

Bret: Yeah. Okay, because of your work with Norman and he was, at the time, trying to please the political powers by creating things like what are the maximum compressing loading limits and things like that. Which are very vague. But for your PHD thesis, you wanted to know everything that contributed towards these loads. So what was your thesis on?

Stu McGill: The first objective was to build the most biofidelic and anatomically accurate model of the spine ever done before. That was the objective. The reason for that objective was two fold. Number one, understand how the spine works with all of the pressures, muscles, and ligaments with all the decrees of freedom of movement. That was the first reason why I did it.

The second one was so could I understand injury mechanisms. What are the conditions that are required to create a herniated disc or a fractured end plate or torn ligament, whatever the injury was. That was the motivation for the thesis. And as you know, we still use that model today. Of course, it’s much more anatomically robust than ever now but we use it to create a foundational knowledge of how the spine works. Then we can ask clinical questions like what was the injury mechanism and how can we best rehabilitate that injury mechanism? Or how did that person not achieve the performance? How did that person achieve super performance? What was the mechanism there? If we can quantify that then we can figure out better ways to train it.

Bret: So most people (it’s almost comical in my field) will say, “Take the bar off of your back for a week so that you have no spinal loading. So you have no compressive loading. It’s good to not do squats and dead lifts for a week just to unload your spine.” But what they don’t realize is that most of spinal loading is created by the muscle, not the effects of the bar working through the body. It’s the muscles themselves contracting and creating joint forces. It’s not just muscles, all tissues can create loading. So if you bend over and the ligament gets pulled tight, then it’s gonna create compressive forces as well. You basically create a model that will look at all of the different tissues and would partition the different tissues. If you have a certain amount of forces, it would tell you where the forces are coming from: which muscles, which ligaments, and which different structures. Correct?

Stu McGill: Yeah. You’ve stated it quite eloquently. In the first description is that you have a very accurate description of the anatomy. These blocks of bone held together by discs and ligaments. So as you move that spine out of its elastic equilibrium, which is its rest neutral position, the ligaments tighten up. As they tighten up, they impose forces on the various skeletal parts of the spine. Then we do what’s called stress mapping so we know the tolerance and strength during the various modes – compression, bending, shear, torsion, twisting, tension, etc…of the various boney elements. Then as the stresses develop in these passive tissues (ligaments, discs) they stress the connections of the bones. Then we just map it and watch when the applied load gets close to breaking tolerance of that particular boney element or disc element, or whatever it happens to be. So that’s the first bit of it and that’s why we – you saw our infrared system where we create an avatar of the person. We create a skeletal avatar so that as that person moves in 3D, our skeleton now moves in 3D driven by their own personal movement patterns.

Bret: Let’s elaborate on that. For the listeners, if you go to my blog the posts include pictures of me (link: https://bretcontreras.com/a-day-with-dr-stu-mcgill/). First of all Stu, I wish you hadn’t taken me out to breakfast and had me order the biggest breakfast on the menu.

Stu McGill: That’s where we take our big athletes when they come in for testing. I’ve gotta feed these boys.

Bret: My stomach’s bulging out. I was embarrassed. But the deadlift picture was good. I looked very strong because it’s hiding my belly. But the other one wasn’t. If I knew you were gonna be taking the picture I would have sucked in my stomach. Anyway, you see me hooked up to a bunch of electrodes and motion sensors. Then with the deadlift picture (for example) you can see that I’m standing on a force plate. You can see cameras around the room, the cameras are using infrared. They detect the sensors on my body. That creates the 3D avatar.

You can look at the computer screen and see; it’s like the movies. It’s like you see in those animations where I look like a robot and it’s kind of funny because I could see in my physique that I have these big adductors and I could tell that it was my own personal physique. That model picks up your joint motions. You’re standing on a force plate that is detecting the forces on the force plate. The vertical, horizontal, and lateral forces that are put into the ground as you perform exercises. And then all of the electrodes are sensing the electrical activity of the muscles. This is all fed into that model that Stu is discussing. This anatomically accurate model of all the parts of the body with the spine, the vertebra, discs, ligaments, muscles, the fascia. That’s all blended together to tell you forces so that you can get a ton of different data out of that. If I do a dead lift, you can tell the EMG of the muscles, you can get the spinal motion, the hip motion. You can calculate the spinal forces. There are only a few laboratories in the world that can do this. That’s why I felt so privileged to be there because this is rare. The only other laboratories are on other continents. I was very privileged to be there. That kind of explains this method – the McGill method if you will. Is that what you would call it Stu?

Stu McGill: Well on a real life person’s side, yeah I think I took you into some of our labs where we actually take spines and create the injuries. That’s a whole different technology. Certainly for that lab we tested you in, that’s what it does. I’ll send you some of your avatars when they get fully up with the full stress mapping done. You can put them on your website if you want.

Bret: It would be hilarious to see a robotic Bret. Yeah, robotic hip thrust or robotic dead lift.

Stu McGill: Just so your listeners know, that’s exactly the same technology that was used to make the movie Avatar, Pirates of the Caribbean (when they have all the zombies walking). Those are actors driving their avatars with their motion that those 3D infrared cameras pick up. Then they create the skeleton and then render the muscles on and activate the muscles with the EMG. So it really is light years beyond an MRI, CT, or anything like that. Because it’s 3D and as the person activates their muscles, we measure that activation profile through the EMG and convert that to force; attach those forces to the skeleton; do the stress analysis.

Most importantly, we go far beyond that and even measure variables such as joint stability. So when we hear about how this stabilizes the spine. Well, does it really? I find a lot of people talk through their hand waving saying that this is a spine stabilizing mechanism when it may very well be destabilizing.

Bret: Awesome. In a few questions, we will talk more about the EMG aspect of that. You worked with power lifters early on. Was this the 80s or 90s?

Stu McGill: No. We worked with all sorts of people. But I have a sneaky suspicion of where this conversation is going. That’s middle 80s and a lot of the top Canadian power lifters happened to be training in Kitchener. Are we to talk about the actual stories?

Bret: Basically, what I want people to know is that you’re not just some lab geek who always stayed in the lab. You have seen world class dead lifts. You’ve worked with strong power lifters and strong men. You’ve worked with incredible athletes and seen it all. I think that’s important because I don’t really trust someone if they haven’t. If they’re gonna make comments about athletics and movement, it’s important that you’ve been around the block and seen and worked first hand with these people.

If you were working with power lifters in the 80s, that just goes to show your 30 years of working along-side of the power lifters and the athletes. Your initial work was mostly focused on injury prevention with occupational workers (for example). Then over your career, you’ve seen more of a transition into working with more of the athletes and the strength and conditioning field.

Stu McGill: That’s correct. Again, not all of this was by design. Some of it was by happenstance. I mean as you know, I get asked to consult and see athletes from around the world. I don’t even see local people. Every patient I see flies in. They come from all sorts of sports. I guess I’ve got this little reputation that if someone has a painful back that I can usually give them some advice in how to train around whatever the cause is. We see if we can create a performance enhancing program that will restore their backs and get them back to competition. Again, I can’t talk about individual names obviously because it’s medical confidential information. But there are quite a few people who have told their stories where we got them back to the Olympics or back into the NFL or back in the UFC – whatever their sporting endeavor was. So we took them from a state of being unable to train because of their disabling back pain, to the point where they could be elite performers in the world of virtually every Olympic sports – rowing, weightlifting, the combative, track and field, kayaking.

Bret: Basketball.

Stu McGill: Certainly. I’ve consulted with a number of NBA basketball organizations for sure. Anyway, I’ll stop that.

Bret: Were you always comfortable when people came to you for advice as a practitioner. Were you always comfortable giving advice?

Stu McGill: No. I was scared silly. I mean look, you got it. I was trained as a scientist not a clinician. I would be asked to go to scientific meetings: neurology meeting or an orthopedics meeting, or a sports medicine meeting. Some of the docs would say, “You know. That’s really interesting. The mechanism that you just showed for that injury and the recovery. Would you see a difficult patient for us? This patient is a foxing us.” I would say, “No. I don’t see patients.” They would say, “Well it’s okay. We’ll be with you. Would you come and see this patient with us? And show us how you think and interpret what you see.”

So that’s how I started working side-by-side with them and then slowly realizing that what I was able to see and understand because of what I was seeing about the mechanics associated with pain, elite performance, and that sort of thing. I gained confidence to see people on my own. So how it works now is if an athlete or a disabled vet wants to see me, I send them a package (which is an information package) with travel instructions and that sort of stuff. Then I need a referral letter from the referring physician. It will say, Please see so and so for mechanical back pain. Here are some of the peculiarities that should know. And there might be a kind of contraindication for a certain type of exercise or blood pressure or something like that. Then I see the person.

It takes me 3 hours, at least I set aside 3 hours, for an assessment. Which includes pain provocation. So I’m able to identify that the triggers of their pain, in terms of very specific motions, postures, and loads. Then to design a program for them to avoid their painful triggers. That’s number one. I don’t do corrective exercise off the bat. The first thing I do is remove the cause. Then we devise a corrective exercise program. Then a full on training. It makes me laugh sometimes when people say, “Oh. We did the McGill exercises.” And I say, “What in the hell are the McGill exercises?” They say, “It’s the bird dog.” And I say, “Have you ever read my books? Do you know what we do?” We have people picking hundreds of pounds off the floor and throwing men around the room. the McGill exercises – it’s quite comical sometimes.

Bret: It’s funny you talked about it’s purposely provoking their pain to find out what are the mechanisms that cause pain and telling them to avoid that. That’s so simple and so often overlooked. I can’t tell you how many people come to me and they say, “It hurts when I do this.” One of my favorite articles ever written in strength and conditioning was by Mike Boyle. I think that the title was ‘If it Hurts, Don’t Do It’. He talked about the same thing. Now that I’m more popular on the internet, I get all these emails from people saying that it hurts when I do this… so I say “Don’t do that!” It’s just common sense.

Stu McGill: You know what the tragedy of that is Bret? When I get a person, I’m never the primary contact. I’m further down the tree. They’ve already been to ten different doctors. And I’ll say to them, “Have any of those docs ever asked you to show them how you create the pain.” They’ll say, “No.” And I think that man, what an indictment of medical practice; or at least the people who they saw. They failed to try and understand the cause of that person’s pain.

Bret: That’s a whole other podcast topic. I can’t tell you how many people come to me and say, “My doctor, physical therapist, personal trainer says that I have a weak core.” Okay, did he test your core? What exercise did he give you? It’s just that person was using buzz words and the patient is gullible so they’ll believe anything. It may be that they have too strong of a back and that they are trying to use their back for everything. It doesn’t always mean, just because you have back pain, that you have a weak core. A lot of times, it’s not strength but your movement patterns. You have the strength, you just need to learn to move differently. Okay moving on.

Stu McGill: Can I just follow that up because what you said is so wise for the listeners? May I have one minute on that?

Bret: Yeah. Of course.

Stu McGill: We’ve done enough of studies on populations. We’ve done sporting groups, factory workers, line distributions, guys who climb hydro poles. It keeps coming back, over and over, that strength as a single variable does not prevent back pain. I’m using that very generically because there are all kinds of back pain. What happens is that if you think you’re gonna get rid of back pain by getting a stronger back, then you might be in that category of person. But that’s not the common pattern. The common patterns of people who get back pain have almost too much strength and a movement pattern that causes that concentration at the area where the pain is. It’s almost incumbent on every strength and conditioning professional that if you add strength to a person, the pattern better be there so you don’t create a stress concentration and Gray Cook preaches that until the cows come home. You have been preaching it as well. If you have a lot of strength, you have to have control and you need a certain amount of endurance because that strength has to be harnessed over and over again with every repetition. People get hurt when they break form. They don’t get hurt when they pick 800 pounds off the ground if they do it well. When you talk to them, it was the one that they were not paying attention on. You know what I’m trying to say.

Bret: And I can’t tell you how many times I’ve heard this. It’s funny because I’ve been lifting weights since… well a friend on email just reminded me on Facebook. He said, “Remember when we went to this gym?” I wrote him back and replied, “How old were we?” “15 years old.” I’ve been lifting now for 22 years and I’m just finally learning to listen to my body. Over the last 5 years in particular and if you just learn to listen to your body I can’t tell you how many times in the past decade where I got hurt and my body was screaming at me, giving me warning signs. You just have to listen to bio-feedback and learn when to push and when to hold back and to pay attention to what form feels better and what form doesn’t. Your body is good at giving you warning signals, you know?

Stu McGill: Yeah. I’ve been lifting weights for double the length of time you have. I don’t know why I said that. I’ll just mention this because you’ll appreciate it. Are you familiar with…

Bret: Because you are big timing me Stu. You just wanted to throw that up there haha.

Stu McGill: No. It was quite the opposite. You young bucks I’m trying to keep up to. My old body just doesn’t hang in there anymore. You’ve probably heard of Marty Gallagher.

Bret: Yup.

Stu McGill: One of the grand old men of power lifting and Marty, if you ever listen to this, he’s gonna bust me for calling him an old man. In any case, Marty is older than I am. Do you know Marty has picked up 500 pounds off the floor for five consecutive decades?

Bret: That’s great.

Stu McGill: Now you listen to him because he’ll tell you how you manage that. Yet, both you and I will take a lot of flack from kids on the internet who are anonymous saying that we don’t know this or that. And I think man, I think I should be listening to the guy whose done it for 5 decades.

Bret: That leads us to the next question. You mentioned to me that it’s hard because sometimes I would kill to be in your position, where you don’t have a blog and you don’t have to deal with blog comments. Me, I have Facebook, YouTube, Twitter, Instagram, email, text messages, and I got these things flying at me all day. Sometimes I’d kill to be just like you. My supervisor John Cronin laughed at me and said, “Man, There’s something nice about being inaccessible.” Your work is that people hear snippets of things you say. Then it’ll blow up into this thing where if they were to talk to you about it, they would see that there’s more of a common ground that people don’t get to see.

Stu McGill: There’s a lot of mythology and misunderstanding and the quotes that I keep hearing over and over again. Well, do you want a reaction to that?

Bret: Sure.

Stu McGill: It reminds me of the old kids school ground. One kid says something to another and it starts a rumor. The next kid passes it on and it gets slightly translated. Then the next kid passes it along so by the time 4th kid gets it, it resembles nothing like the original bit of gossip. I think that’s what happens on the internet so now there’s this thing that apparently McGill thinks that there’s a number of bends that hurt the back. Or there’s a load that hurts the back. You know, they just don’t know what they’re talking about.

I talked about that whole political process. If they realized there is a branch of the American government called NIOSH (National Institute of Occupational Safety and Health). They go around and ask experts their opinions on strategies to protect the American worker. They have single number limits called TLV (Threshold limit values). For things that hurt Americans. You know, there’s one for radiation exposure for example. Now there’s a limit that if you’re exposed occasionally, there is a limit and if you exceed the limit then it’s legal negligence. There’s another limit that you must never expose an American to X amount of radiation. But you see, it’s a single number. That single number might not hurt one person who’s not very sensitive to it. And it might really hurt someone else. Another example are the nutritional guidelines put out by the government where there’s a daily healthy of let’s say vitamin D or Vitamin C. These are all values. What person is average? The answer is nobody. It doesn’t fit anybody! Now people will be surprised to know that NIOSH has a single number limit for low back compression. That limit, if you’re exposed over and over again, happens to be 4300 Newtons. Now let’s go to post office. There’s a 62 year old lady at the post office lifting boxes. And there’s a 22 year old, big strong guy lifting boxes. Do they have the same tolerance? No. Is the number of load that their body can take the same? No, it’s not even close.

But the American political system will not allow the discrimination between old and young. We all realize that biologically it’s ludicrous. So when I have made a statement, it’s at the request of a body to come up with an average number based on a lot of science and a lot of perspectives. It’s not pigs and it’s not an animal. It comes from many different perspectives. So that got translated through that schoolyard banter to the next person who wrote something on the internet. But they had no idea the political contesting and gravity of when that statement was made. So now kids go through the internet and say that Bret doesn’t know what he’s talking about. McGill doesn’t know what he’s talking about. Because of that one number. They are just totally unaware of the process of it all.

Bret: Stu. The higher up you get and the more popular you get, the more you have to deal with it. On my blog (a couple of years ago) I had a fourth of the readership that I have now, and I flew under the radar. Now anything I say I get hammered for it I feel like. If someone misinterprets it, I definitely understand there. Not trying to cut you off, but you mentioned the 4300 NIOSH compressive loading limits. I have a folder of research involving compressive loading. And also shear loading. I think the highest I’ve ever seen is a deadlift and this, I think, was Callahan? Was this your student who published this paper and it was on deadlifts and I think it was 23,000 Newtons of compression?

Stu McGill: No. His name, it looks like Cholewicki (HERE is the paper).

Bret: Oh yeah, that’s right.

Stu McGill: He’s Polish. Anyway, he was my first PHD student.

Bret: Now there was a paper before that by Granhed (HERE is the paper) that showed like 35,000 Newtons. But they used a different moment arm. So the Cholewicki was more accurate.

Stu McGill: No Bret. Nope. I’ve listened to Granhed as well because the load lifted these days are a lot more than the loads lifted in those days.

Bret: Well that’s what I was gonna say. If you think of a Andy Bolton (Or Benedikt Magnusson) deadlifting a thousand pounds, I would think that they would have more of the lines of 40,000 Newtons of compression.

Stu McGill: You’re right on!

Bret: And this just goes to show you what you said earlier, you know that you can build up the body to be very strong. The muscles and as long as you hold good position and your training parameters are proper, your frequency, volumes, postures, load, all these things, you can build your body up to withstand that. The body is a very impressive unit if you train properly.

Stu McGill: Some people can’t.

Bret: Well that’s what I would like to talk about. Okay, I’m gonna veer off. You mentioned genetics as it pertains to the spine. Talk for a second about ovoid and the limacon disc shapes.

Stu McGill: Just let me preempt that by saying that McGill learns everything from pig spines, which again just annoys me to no end. We use animal models in about 10% of our publications in medical journals. We have to use animal models to answer the question that you just posed. So I can’t get 50 identical human spines. They don’t exist. But we can raise 50 identical pigs, at least from genetic material.

Anyway, the pig neck, the pig roots for food. It has a very robust lumbar spine in its neck. It can’t move it very much. The fact that it has to hold its head up since it’s a quadruped cantilever. The head is out in front of the body. All of the time it has to turn on the extensor muscles just to hold its head up. So when you look at the architecture of a pig neck. If I showed a pig neck or vertebra to a human surgeon, and we do this in the lab, they don’t know whether it’s a pig C4 or a lumbar C4 out of a human. They are that close.

So people don’t realize that but anyway, what the animal models allow us to do is we can have a variety of disc shapes. We inherit that from our parents. If you take a slice through your low back, you will look down and bird’s eye view and see the shape of your disc. Some are oval. If you twist an oval disc (an oval disc likes to twist). The great golfers, not all, tend to have ovoid shaped discs simply because of survival of the fittest. If you can’t swing a club very well and you can’t twist, then you’re going to choose another sport besides golf. People with these slender, oval discs tend to become golfers. Those types of spines can twist. Now, if you take the typical middle linebacker from NFL, they don’t have oval discs. By definition to survive in that sport, they have to take a lot of compression and they have much bigger, thicker, much bigger radius discs. But they’re shaped like a lima bean when you look down on them. they are big and indent at the back where the spinal canal is. When you get a thin branch and bend it, it will bend. There’s not much stress. But if you take a thick branch and bend it, it breaks. That’s what happens with very thick discs that tend to be limacon shaped. The hydraulic stresses that come from bending in big heavy spines get focused to the back of the curve of the limacon and these kinds of people end up with posterolateral disc bulges if they bend too much.

Bret: Real quick. Stu showed me this in his lab. He could show the herniating mechanism.

Stu McGill: I hope I’m making my point in that we all have different spines. So when we’re looking at the physical performance from a person’s back, it depends on its shape. If they have a thick spine, chances are that they shouldn’t be doing hundreds of sit-ups. In fact they can’t. The stresses would accumulate and they would damage their backs. But if you take a thin person who naturally gravitates to yoga and these kinds of things, they can bend their spine around with relatively little stress and very little chance of harm. Again, I get quoted that there’s a certain number of bends. It depends entirely on who the person is. So when we’re consulting with a particular athlete, we examine all these features and try to convert on the most common sense approach. Depending on the shape of their discs and previous injury patterns. For example, when we see a tear in the annulus of the disc, I can almost bet that it’s a twisting injury in their spine. Then we look for that pattern and try and help them remove it. But if it’s a very focal disc bulge, then that’s probably an interior bending injury.

Bret: One thing that I always wanted to know about was if you read a lot of the work of, who is it, Dolan? Michelle? Is that the right name? She says there’s a lot of spinal research that talks about heredity as it pertains.

Stu McGill: Hold on. There’s two people who do that. There’s Michelle Battier at the University of Alberta, that has a lot to say about genetics and particular types of back disorders. Trish Dolan is at the University of Bristol in England.

Bret: Okay so they’ll tell you that they have…I’ve seen estimates at 85% or something like that of that. What was interesting to me when I was doing a ton of spinal research a few years back was all of these different chemicals. So you talked about the anatomy of how genetic anatomy can affect spinal durability.

But there’s also physiological genetics, I wouldn’t just say genetics. I bet you lifestyle can affect this a lot as well. There’s all sorts of chemicals and I can’t remember all the names but there’s like metalloproteinases that can wreak havoc on disc health. There’s a lot of anabolic chemicals like IGF 1 and things that are like, God I can’t remember all of the names of them. I wrote them down at one point. There were like 11 different chemicals I had written down that can have therapeutic or anabolic healing, repairing effects. Then there’s other chemicals that can break the discs down. Different individuals probably have varying percentages of these as well. So that probably has a lot of influence over spinal health and durability. Would you agree?

Stu McGill: I’d absolutely agree that they have a biological spectrum and that they can cause different rates of repair in different people. The total ability of them to create total repair or how influential they are might become a question for debate. They will not be the dominant factors in whether your back pain gets better or not is my position at this time. They will have smaller effects but if you can’t get rid of the cause, or if you’ve flattened a disc, then there’s not a hell of a lot those chemicals are going to do to restore the height of the disc.

Bret: I guess what I’m trying to say is that if they do something if they have, whatever the injury, whether it’s shear related, compressive related, bending related, if they’re only doing it every few days. Or once a week, twice a week. But they have good reparation systems. That injury may never appear versus in someone else who does not have them. For example, smoking can affect the disc physiology. Am I right about that?

Stu McGill: To a very small degree, yeah.

Bret: The reason why I’m saying this it’s not pure physics. The word biomechanics implies that there’s the physics but there’s also a biological component as well. There’s a living component.

Stu McGill: You’re absolutely right. Let’s just go back to that point you just made because that was a very important one. You can build a little bit of cumulative trauma and then the disc will repair if you leave sufficient time. And then have another cycle of loading. In some sort of interval sort of training situation you want to be careful with that assumption. The muscles absolutely will follow the law that you just described. The collagenous tissues, yes, but not quite so well. The disc even poorly still. So building trauma, delaminating the collagen in the disc will not repair in a week and it may not even repair in a year. It’s that slow.

So folks need to understand, I think, be very careful with accumulative loading. Now, I’m not talking about pristine good movement. The spine is really quite robust if you load it in an…say you’re putting high loads on it, the very best thing you can do, the safest common sense thing, is to keep it in a neutral position with a high load. If there’s not high load, then I’m not so worried about it unless you already have an injury. If sitting is painful and a certain sitting posture bothers you then you better not sit in it. But if the spine has no cumulative load, that’s a very common sense wise practice. To do a little bit of bad form and then think you’ll take a few days off and then do the same thing once again, that will accumulate and it will come back to haunt you.

Bret: So moving on. Earlier we talked about EMG. A lot of spinal models don’t utilize EMG. They just make assumptions that if you do a squat lift or a stoop lift, they just look at joint torques. Sure you can get the net joint torques but you’re making assumptions about the muscles. Why is it critical to throw EMG into the mix? To incorporate muscle activation into that model?

Stu McGill: Because we all use different motor strategies to accomplish a task. When you were in the lab a couple of weeks ago, we tried a few little training interventions. We tried internal/external rotation of the hips. We tried some little strategies to see if we could migrate muscle activity between the glutens and hamstrings. So we did all of this. We’re able to do that because we were measuring neurology while we were doing it. We were measuring the personal differences in your muscle patterns. Those are all going to create very different joint loads. So we then have the ability to say, “You know Bret. For you, if that exercise tool was to achieve this goal, that was a wiser exercise. This other one, this variant might have been a poor choice. Because not only did it achieve the activation level that you did not want, but you also paid a hell of a penalty for doing so by having a very high joint load.” That’s why EMG is so important. To pick up the individual differences.

Bret: So for example, if I do a squat lift or a heavy squat, should I…first of all, I’ve heard a lot of experts claim that the squat and deadlift are the best abdominal exercises that you can do. In which case, I just know that they’ve never measured EMG because there’s exercises that – for example, an ab wheel rollout that exceed the activity of the abdominal and oblique muscles that you get in a deadlift. That aside, let’s say it was the best abdominal exercise. Those place the greatest challenge on your abdominal muscles. Luckily that’s not the case because if so, in order to keep spinal stability…now, you have co contraction which stabilizes.

However, if you are creating a flexion moment with your abdominals, if you’re actually crunching down with the abs and not bracing, the more you activate your abdominals and erectors, the more your erectors have to do now to stabilize the spine to prevent flexion of the spine. So two questions here. If you didn’t look at EMG and you just looked at joint torques, you might assume that this person is performing optimally because maybe their net joint torques were low and the spine stayed neutral and you just assume that their spine stayed neutral so they are fine. But you might find that they are so highly activating their core muscles that they’re creating tremendous joint forces and spinal loading. Which is unnecessary if it’s a lighter load. So that’s one reason why EMG is critical because you can look at the co-contractions. When you co-contract, you create stability but that comes at a penalty with increased joint loading. Talk about that real quick Stu. Do you want to activate the abdominals to their greatest possible degree when you do simple tasks?

Stu McGill: Of course not. I think the term you’re looking for is called sufficient stability. You need just enough to accomplish the task without the spine buckling – well, I need to get into that stability concept in terms of mechanism to really answer this question. The short answer is you need sufficient stability. Any more would be silly. You’re just crushing yourself.

Bret: When you hear people say, “Squeeze your abs as hard as possible.” That’s not the wisest strategy in that situation.

Stu McGill: I think you’re dealing with someone who’s very crude.

Bret: You had mentioned a very cool story to me. You were on the path to – you were limping and this was in your thirties. You had some calcification or growth on you labrum. You were limping and on your way to get hip replacement surgery and you took matters into your own hands. You started exercising and performing certain movements. And that spur on your labrum diminished. Your posture improved and you prolonged the surgery, in fact you’ve still not had hip replacement surgery. That was a very cool story because you took matters into your own hands. Can you describe to me what you did and what mechanisms would cause your labrum growth at your hip to improve itself. Because you don’t see that too often I wouldn’t think.

Stu McGill: The story starts, I broke my hip. If you look at it on an x-ray, instead of there being a nice femoral head it looks like half a ping pong ball. It’s the inner half, the medial half that is just a fat pad. So the joint itself was quite unstable. It became quite arthritic. It was about when I was forty-five years old, I was starting to have really terrible hip pains. The hip socket, the acetabulum was growing nasty spurs all around it, like little teeth almost so that when I extended and walked, one of these spurs would poke the femur and it would cause me to lurch forward and limp and people who knew me when I was in my forties knew that I had quite a nasty limp. Anyway, I arranged a hip replacement with one of my surgical colleagues. I thought what the hell, I might as well just exercise the hell out of the hip because it’s going into the garbage bin anyway and get myself in the best possible shape for post surgery recovery.

It was at that time, it was a very magical time, in that we were talking earlier about serendipity and how you meet people and they change your life in funny little ways. At that time, I had met Vladimir Janda, who I think you’re very familiar with his work. Janda was talking about all this cross pelvis syndrome where hip pain and back pain inhibits the gluteal muscles and facilitates the psoas. When I measured this on myself with the EMG and the model, it turned out to be very true. Then Shirley Sahrmann came along and I did a little bit of work with her at the time. These are all just brilliant, insightful clinicians. Her work was showing that as Janda said, if you have hip pain, then your gluts become inhibited so you become hamstring dominant. When you get out of a chair and do squats or get off the toilet or any of those functional things, you tend to extend the hip with the hamstrings leaving the glutes out of the motor control picture. Well what Shirley Simon’s group found and I’m trying to think of her lead researcher on that and I’m embarrassed that…

Bret: It was Lewis.

Stu McGill: It was! It was Lewis! Thank you! Bret, you’ve got a mind like a trap. Thank you sir. It was Lewis and Sharman and Ben Dillon were on those works as well. In any case, when you use the hamstring to extend the hip, it pulls because of its line of action. It pulls the femoral head posteriorly. Sorry. It pulls it anteriorly and creates an anterior femoral impingement, which a lot of people will be familiar with. However, if you can get the gluteals reintegrated back into the motor pattern and you become glute dominant once again, it pulls the femoral head back out of interior impingement. Well, I started doing hip thrusts and glute bridges and these kinds of things.

But remember now that I was coached by Janda, the brilliant clinician teaching me squeeze my gluts a certain way, push my feet away to activate the quadriceps, and further inhibit the hamstrings and all of these bridges. I didn’t use heavy load. It was all about re-patterning the interplay between glutes and hamstrings. At the same time, I started to take glucosamine chondroitin, MSM and a few cartilage builders. At the same time, I started to get – you’ll notice my physique went much more skinny in that decade. That was all purposeful because all of a sudden, my hips started to get better and I set a goal for myself. Oh if I can only reach 50 years of age with my own hip, that means…because replaced hips only have a finite length of time and I’m pretty active so I’ll eat up that hip and if it lasts 10 years, then I would need a fake hip that would be all I could get. My objective was to make 50. I started to get close to 50 and low and behold, my hip was betting better! People thought I had a hip replacement. Then with our x-ray, my colleagues x-rayed my own hip and I was watching the bone spurs shrink. So the more gluteal dominant I became, the better biomechanics of the hip joint was created. It took away the femoral impingement. My labrum settled down. The hip spurs decreased. The cartilage thickened. Now I am skinny, what am I, 56? I think I am. I would have to do the arithmetic. And I still have my own hip. I don’t limp very much at all now. Anyway, there’s a little bit of a cool story for the glute guy.

Bret: Well it just is so cool because in our field, there’s a lot of talk about how you never want to use internal cueing, internal intentional focus. You never want to tell people to focus on the muscles. It should always be focused on the external environment. Here you have a case where you did focus on building that mind muscle connection to the glutes and you re-patterned in your language, you reestablished gluteal dominance and brought the glutes back into the motor pattern. It changed the biomechanics of your lumbar-pelvic-hip complex.

Now you’ve got glutes pulling rearward on the femur, keeping it more centered in the acetabulum and you aren’t getting that impingement. Now you aren’t getting the pain. Pain inhibits muscle activation so just getting rid of the pain is huge. So you can keep using your glutes and they aren’t inhibited. A lot of people don’t realize this (I didn’t realize this until you told me) but hip replacement surgery is a big deal because it only lasts around 10 years so you’ve gotta get another one. Well, you have to spike that hip replacement into the femur and so you can only do so about twice in a lifetime. Am I getting that right?

Stu McGill: Yeah, you lose so much bone stalk the second time around because they have to bust out the first implant.

Bret: This is greatly impacted your life for the better and it’s just such a cool story. Now, I think you also said it’s the frequency. Every day you would be doing your glute exercises and hip thrusts and bridges. But also, I have heard from other interviews that you get down to a deep, full squat. You aren’t using weight. You might go into a posterior pelvic tilt but you’re squatting all the way down and just keeping that ability. You’re not using weight but you’re just going as deep as possible to retain that ability. Am I getting that right?

Stu McGill: Yeah. You’re right on. Again, I’ll tell another story so the listener-ship is starting to appreciate that these brilliant people have fantastic influences on my life. There’s Janda, Sahrmann, now the next one is a fellow named Jerszy Gregorek. He was a Polish weightlifter. He now lives in California. He wrote the book called The Happy Body. Which is a really wonderful read.

Jersey is a former Olympic lifter. I think he has 3 or 4 world records. So he’s very competent. Now we used to discuss the old sort of Soviet block and Polish weightlifting routines. He said, “Let me have a look at your hip.” This would have been, we met at Craig Liebenson’s place originally, that probably was right when I was in my – no this would have been after Janda. I’d still be in my forties. Jersey said, “I’m gonna give you some advice with that hip. Do one deep squat every day.” And I said, “Jersey, that would turn me into a cripple.” He said, “Try it. Don’t use any load. Hold onto a pole or a table and keep your body vertical. Go down and when you get to the bottom, sink into it. Let all muscle tension go. Get into the deep squat and just go and sit into it. Take all the tension out.” And after a few days, I started to feel again, a change and it was a change for the better. So my hip with what’s left of it now, I can’t squat with a bar on my back. I can’t do Bulgarian split squats. I would love to do all of that stuff. I can’t. It would flare me up so I’d be crippled again.

However, there’s another little piece of the puzzle and I used that with my patients – all of these wisdoms. I use in making decisions I wouldn’t use them with every patient of course, but it’s helped me in making these decisions. One deep squat a day, sink into the bottom, preserves the squat ability. But it’s so spares everything else in your back so these guys that say, “You gotta deep squat with heavy load.” Really? Let me see then when they’re sixty.

Bret: This leads is right into the next question. We talked about the butt-wink squat, which the technical term would be posterior pelvic tilt. There is a relationship between posterior pelvic tilt and lumbar flexion. There are very few people who can actually achieve a rock bottom ass to grass squat if you will and keep a solid anterior pelvic tilt and lumbar extension. Most people lose that arch with some people losing it before they even can reach parallel and other people not. This is very influenced by genetics and which country you came from.

But we talked about this Stu. We talked about butt-wink and why some people improve on it. I actually filmed a video on this. I used a little Halloween skeleton I called Skelly and showed what we talked about. People can improve this ability but it is genetic – there is a genetic limit. So talk about the difference types of hips Stu and then also talk about why you can improve it over time if there is some genetic – like an anatomical limit. How can we improve upon it?

Stu McGill: Okay, great question. When you do a deep squat, there are several components that determine the amount of motion that they have. Of course, there is muscle tightness. But if you’re doing the squat then that’s overridden. That’s probably not gonna matter much. There’s the joint capsule, neural tensions, and for the clientele I see, people with disc bulges and traps in their back, that matters. The neural tension that they will feel through the piriformis area behind their hip and what not.

But the most important matter on all of this is the depth of the hip socket. If people are looking up on the internet, depth of the hip socket and squat ability. they won’t find it. They have to go to the hip dysplasia literature. What they’ll find is that there are groups in the world with very shallow hip sockets and they have very high rates of hip dysplasia. The center of the world for hip dysplasia is Poland. They have very shallow interior hip sockets and they can squat very deeply. The femur comes right up because there is no bone on bone contact there.

It’s actually called the Dalmatian Hip, which originates on the Dalmatian coast of Croatia up through Bulgaria into Poland and into Western Russia, which is the Ukraine. Now I think I just named the countries that produce year after year, unbelievable Olympic lifters. They also have the highest rate of hip dysplasia. So again, it’s form and function – and form and function determines athletic ability. It determines where you become arthritic and all the rest. It was very interesting. I occasionally do legal cases as a spine knowledge source (I guess) and I worked on a couple of murder cases believe it or not, where they needed some spine expertise. And another one of the scientists was a professor of forensic anthropology. It was her who first showed me all of these different hip architectures and how they change throughout the world. So it helped her to identify bodies when the skin and the hair and other features were burned off, say. That’s the Dalmatian hip, which is ideally suited for deep squatting. Now you take the archetypical shallow socket hip and it’s a very deep hip socket and that’s a Celtic hip, prevalent in the Normandy area of France, Ireland, and Scotland.

Now how many Olympic lifters come from those countries. Not very many. The reason is they have very deep hip sockets and when you measure the power production out of that hip architecture, you’ll find that they don’t have much power at the bottom of the squat pulling out of the hole to use an athletic term. But the top half of this squat is really powerful. So for throwing the caber and things like that, it’s a standing strength or a very shallow squat strength. That’s where the power is. Am I saying that all Scottish people have deep hip sockets and that all Polish have shallow? No I’m not. I’m just saying that’s the tendency from those genetic pools. Anyway, that’s a start to the discussion. And it’s not that I care where you’re from but what it motivates me to do is a hip exam. As you know, I have an assessment DVD where I show these techniques and then I can start answering the questions to guide athletes. Should they be squatting deep? Should they be concerned about butt-wink? Or should they avoid that because they’re stressing the interior labrum of the hip. They are stressing their spines. Chances are that they are gonna survive a lot much high volume of training if they pull off blocks. So they only squat deep enough where they can save the labrum of their hip and save their spine. You know, say you’re an NFL lineman. Why do you need to deep squat if you’re an NFL lineman? Why not just squat as deep as you can to the point of where the pelvis starts to break away? Because that’s where the femur is collided up against the labrum of the hip anyway. Take all the stress out. You’re still gonna play offensive tackle in the NFL just as well. You’re still gonna get strong and better yet, you can now tolerate a higher volume of training because you’re removing that stress riser. That’s a key for a lot of people.

Bret: Amen. I completely agree with you. I mean, really how much difference is it gonna make if the person is doing squats just above parallel versus squatting deep if they’re already world class athletes. It will prolong their career. So the training must suit the individual. So answer to me the second part to that question: you will notice some people – this happens with my clients a lot – they’re butt-winking like crazy and then they get better. They actually can go deeper over time and hold that position. What’s happening there?

Stu McGill: Well, I would speculate that when you do a hip exam – I think I did one on you, did I now? Or I scoured your thigh around an arch looking at the shape of the acetabulum so we could determine optimal knee width?

Bret: Yep.

Stu McGill: So you could squat deeper. So you know what I mean by that. You can actually tune an athlete. What I mean by that is that if you can adjust their foot width in the setup of the squat, and as they are descending, you might want to coach, “Don’t try and spread your knees. Don’t try and spread the floor. But try and open your hips, abduct your hips.” You can coach them into that nice little pocket in their acetabulum which is the stress riser. You determine that by doing the hip exam. So it might be coaching.

Bret: Real quick Stu, let me clarify this. This hip exam, you can basically get people into positions and this can be quadruped or it could be supine. But your playing with their leg and figuring out which width elicits maximum squat depth without losing the spinal arch. That way, you can determine a proper stance width for the individual. So this is the way their stance width and foot flare should be that actually maximizes their squat depth. That’s gonna allow them to go to the deepest without creating the most damage. And it’s different for different people. Some people feel better out wider and some people do better narrower. Correct?

Stu McGill: Exactly.

Bret: So they are improving their motor control. You’ve got muscles that are working to keep them in that groove. You also can have muscles potential pulling and doing things to keep – you know, like say the glutes for example: Pulling rearward. That could actually help some people possibly achieve a little bit more depth just by creating some space in the anterior hip socket. Is that correct?

Stu McGill: That’s not a maybe Bret. That’s an absolute definite. That’s absolutely true. If they are descending and they can use the glutes in eccentric control, it’s not in everybody but a few people. They can now get deeper into the squat because they de-stress the anterior labrum you see. They pulled the femoral head back. You’ll find there are a few athletes who can achieve that. Not everybody of course.

Bret: Okay, so next question. We talked about this and I’ve experienced the same thing with my EMG testing. It’s very fascinating. When you work with everyday people and you’re testing EMG, most people don’t realize is that they’ll see something like over 100% of activation and they don’t realize how can you get over 100%? You have to normalize the data so you have to choose either a basic position or exercise. Like you could do a bodyweight squat or an MVC position where you try and elicit a maximal contraction out of them. Then when you do the exercises that you’re testing, you’re comparing it to that activity. Otherwise, you just get the millivolts which doesn’t really tell you much. For example, the glutes have fat covering it. You’re gonna get lower millivolts. So when you test MVC, when you test athletes versus average Joes, the average Joe is not very good at activating their muscles. They will get way higher when they do the exercises because they don’t have good mind/muscle connections or good motor control. Athletes do way better. Is this true Stu?

Stu McGill: Yeah. There were two thoughts going through my mind listening to you. One is this idea of the brain’s ability to send neural signals to the muscle. We’ve all read documented cases where, say, a woman has seen her child under a car and is now trapped. Well documented, she went over and picked up the front of that car as someone pulled her kid out. She lost her hips and fractures vertebra but somewhere she summoned the ability for her brain to send out super potentiated volume of signals to her muscles to contract with such intensity that she picked a car. Correct? These are well documented. So that just goes to show you that people have this ability deep down, somewhere in the primal brain. The great athletes become much cleverer at inhibiting the inhibitors. If you know what I mean by that? We had a good discussion I recall about inhibiting the inhibitors and Doctor Frank came into my office, he’s an expert in inhibiting the inhibitors when we were talking about this. Athletes become clever at learning to inhibit the neural inhibitors so they actually send stronger, denser signals to the muscles. That was one thought that was going through my mind.

The second thought – and bodybuilders by the way. If you measure an accomplished bodybuilder. They spend a lot of time posing in front of a mirror and simply with their brain, activating muscles and getting them to stick out. So if you say to a bodybuilder, “Give me some serratus anterior.” Man, they give you terrific signals. You go to the average guy on the street and coach them, “Here’s what I need to do to get serratus anterior.” They have no clue what you’re talking about. They are completely at a loss at how to activate those muscles. That’s one very interesting feature of athletes. The other is more petite in muscle contraction physiology. Most people, I hope are in strength and conditioning anyway, are aware of the motor pull within a muscle. There are motor neurons that stimulate the muscles that contract associated with certain fibers. They are intertwined throughout the muscle. There are fast twitch and slow twitch but there are all sorts of subcategories. It’s not just fast twitch and slow twitch. There are certain motor units that only get activated during rapid concentric contractions.

There are others that only get really activated as you’re really releasing force or controlling an eccentric contraction. In other words, to really stimulate the full family within the motor pool of a muscle, you need a variety of contractions. You need slow grinding strength, very quick rapid strength, etc. So now we can talk about the MVC. That is an attempt by the scientist to get maximum voluntary drive to the muscle and you do it in an isometric contraction. In the great athletes you get them to mentally focus on it and as you cue them etc.. Say you were doing a leg muscle, then you simply get the person to walk or run and even just a mediocre pace of running will recruit a whole new membership in that motor control pool that you could never get, even in a maximum contraction. I sent you some EMG traces today of you which were normalized. But they are not still telling the truth. What the model does is kind of interesting. It takes the EMG signals, which were collected and normalized to an isometric maximum contraction. But as you move, whether the muscle is shortening or lengthening, we take all of that into account. Instantaneous muscle length is also taken into account. Because all of these are modulators of that relationship of the muscle converting the electrical signal through to a muscle force. We still have a lot of work to do on your data that we collected although I sent you the raw signals today and we can say, “Oh okay. One muscle is on more than the other.” Which is true from the sense of neural drive. The question was, were they producing more force or not. We can’t answer yet until we get into the actual joint position of the muscle activity at that instant in time and whether it was modulated by shortening or lengthening and all of these other modulators of that relationship. I probably spoke way too much on that.

Bret: It’s something that kind of ties into attentional focus. External versus internal. Have you had a lot of success in your career using an internal attentional focus. For example, for fixing movement patterns or getting people to direct more neural drive to a muscle. And then eventually that reaches automaticity. That’s the whole goal. You want them to eventually not have to think about using their glutes when they do something. Initially, I’ll just say that in my opinion, our industry goes too far with most things. Something new comes out and it becomes this all or nothing approach. Yes, if I have an athlete who’s trying to set a broad jump record, I’m not gonna say, “I want you to maximally contract your quadriceps before take off.” Or something stupid like that. Obviously, I’m going to give an externally attentional focus and say, “I want you to jump as far as possible. You see this line here? I want you to clear this.” It’s gonna be directing their attention towards the external environment. That’s gonna lead to better performance.

But in my opinion, a lot of the role of the strength coach or the physical therapist is not to maximize performance, but to maximize form and prevent them from injury. I mean, you see these Crossfit highlights (nothing against cross fit) videos that are just ridiculous. That’s what you get when you have a purely external attentional focus on setting records rather than using good form. I personally have found that I had a lot of success with giving people internal cues. Knees out, chest up, squeeze the glutes, you know? Things like that. Over time, they reach automaticity and you can shift more towards external focus. But you use it sparingly. When you want them to set a record, external. When you’re working on form, internal. Do you agree with my approach?

Stu McGill: I’m gonna say yes. How’s that?

Bret: Yes.

Stu McGill: Yeah. I am. But you know, I think you hit the nail on the head in the lead up to that. That is when people take a position that’s dogmatic. They’re following dogma. Always do this. External is better than internal. These are ridiculous arguments. There’s a time and a place for all of these. I said my answer was yes because I agree with generally speaking, when you’re coaching good movement; you begin with the internal cues. You shift to external cues when the person is competent. I’m just repeating what you’re saying. No great person follows dogma. They make decision; they’re not a computer running algorithm that’s based on a dogma. They’re thinking people who are well educated and know their material. They know the person that they’re working with. They pull out the best tool to achieve the goal at that point in time. As the person changes, they will have to change tools. There’s no room for dogma.

Bret: That’s why it’s so important to have a large arsenal over time because you never know when you’re gonna use this tool or that tool and they come up with different people. You mentioned you’re a case study guy. I loved that because you are handed over an athlete, a million dollar athlete, and you’re charged to try and help their back pain. It’s a different situation for every person.

Stu McGill: Would you go for a 50 million dollar athletes?

Bret: Good point. But it’s dependant on their anatomy, their movement patterns, their sport, their goal, their age, everything. That leads us into another question. The universal answer to everything is it depends. Can you comment on that?

Stu McGill: People ask me what’s my position on an issue or what am I gonna do with this person or what’s the best exercise. For any of these questions, the answer is always, it depends. Now tell me about the things that I would need to know to make the best decision. I don’t have a position on anything. All I have is a knowledge base that I have some confidence in and I also have confidence in what I don’t know. I try and seek the best solution but if you put two people in front of me with (for the most part) a certain category of back pain – I might choose a different tool for each person because one has longer legs, for example. There you go. The answer is always it depends. In fact, I teach that introductory course that I was describing earlier. I would pose a question on the board and I’d point to students and say, “What’s the answer to that?” They got it with an “it depends”. I said, “Good for you.” Then I would post another question and ask another student for the answer. They said “It depends.” So that was the lesson for the day.

Bret: I found a quote that I really like from my supervisor, John Cronin. First thing he said to me when I started studying under him, “You know Bret. I always say this. This is how I feel today and tomorrow, as I learn more, my opinion is subject to change.” He flows with the research and I think that’s – we talked about the mindset of an evidence based person. You flow. You are not set in stone. You are not black and white. There’s a grey area. Sometimes we’re wrong. Sometimes we have to change our mind. As long as you use an evidence based approach – which does not mean ignoring anecdotes – it means trying to use all of the tools available and weighing the evidence and looking at research, experiments, logic, and anecdotes, trying to make the most sense of all the different scientific tools out there.

I think that’s one thing Stu. for example, with what we just did at your labs. I don’t know how the chips are gonna fall but I’m interested to see it and I’m open minded to learning stuff that I was wrong about certain predictions. It’s kind of funny. You and I both felt confident in our MVC position for the gluteus maximum to the people still listening now at an hour and fifty minutes in, I said you know, “Stu, it’s gonna be the quadruped hip extension, bent legs with no external resistance. So I’m gonna get on all fours, bend my knee, kick my leg back, squeeze my glute as hard as possible and that’s gonna elicit the maximal contraction in the gluteus maximum.” Whereas Stu had me straighten my leg, get still in the quadruped position on all fours, had me straighten my leg and kick rearward, kind of focusing on extending my leg as far as possible and extending outward and not upward. Then he pushed downward on my leg and offered resistance hip extension. It’s funny because we were both very confident. In fact, we bet that the loser had to buy the other a beer the next time we see each other.

As it turns out, we were both right. Stu’s MVC position elicited more EMG in the upper glutes whereas mine worked more in the mid-lower glutes. That’s a learning experience. You categorize it. You keep it in check. Say, okay that’s how it worked with me. I’d like to see how it works with 10 other people, you know? I think that’s so important for the practitioner to have that type of mindset. It has to be developed. Just like you get better as an athlete, you get better as a lifter, you get better as a scientist as well. You agree with all of this Stu?

Stu McGill: Yes.

Bret: Anyway. Let’s move on. A couple more questions and then I will let you get going. Talk about your thoughts on breathing training. A popular trend in the industry right now is this diaphragmatic breathing. I have not done a ton of research on this but I think a lot of people are like upper chest breathers and they have dysfunctional breathing patterns. Some coaches and therapists have found that if they get people down and work on their breathing, they can take them out of sympathetic – you know, maybe they are relying more on the sympathetic division of their autonomic nervous system. Activating that through their breathing and when they get them to calm down and breathe through the diaphragm and let their abdominal cavity rise first and then the chest. You will turn more to a parasympathetic state. You’ll relax. You’re not mimicking this fight or flight response. You’re gonna possibly decrease cortisol, things like that. I could be getting some of this wrong. That’s just my impression through reading some blogs.

I have not done a ton of it in my practice just because I don’t see a lot of research. I’m waiting for research and I will add that there’s nothing wrong with waiting until research emerges if you don’t know the answer to something. Or you don’t feel confident about it. But I surmise that I wouldn’t want to do this with athletes before a workout because you’re actually trying to get them to prime their nervous system. You want them to be warm and primed for the workout. You don’t want them to be in a relaxed, parasympathetic state. I could be wrong. I think most of my colleagues would say to that, “Well, they are in a sympathetic state around the clock. You want to get them out of that so their muscles can fire properly.” To which case I would say fine, let’s do that at the end of the workout. Again, I don’t know much about this. What are your thoughts on this?

Stu McGill: I’m like you. I don’t have any experience at all in this. I’ve certainly seen people put on workshops for breathing. At these very low levels of demand I don’t know what to make of it. So I’m like you on that. I don’t have the expertise. But I’ve done analysis on breathing in challenge situation and I can comment on that if you want to hear.

Bret: Yep, Sure.

Stu McGill: Okay. When we are doing what we call stabilization training – making this stiff core – we try and breathe freely. Train the breathing. And then perform the exertion. For most of that initial stabilization training, we breathe freely. However, when we start adding load and speed, our breathing instructions and exercises change dramatically. I’m just gonna tell a quick story. I was in a hotel one time just watching tennis on the TV. Venus Williams was on. The announcers were saying, “There goes Venus, really intimidating her opposition today because she would yell.” It’s called a guttural effusion when she served the tennis ball.

I thought that those guys, that maybe sensational but that’s not why she does it at all. That whole idea of guttural effusion adds stiffness to the core. It’s active expiration. We’ve measured this in spades. It turns on the oblique muscles. It super drives them in that instant, you filled the lungs with air and then that first little expulsion is driven by the abdominal muscles. That adds even more stiffness. Now, when she’s serving the tennis ball, let’s just take the example of the pec major muscle – the pec major goes from the rib cage across the shoulder joints, to the humerus. If we shorten and contract the humerus the arm flexes around and moves. But the ribcage also bends towards the shoulder joint. So that’s an energy leak. That doesn’t help swing the arm around. It causes the ribcage to bend. However, if you can fixate and stiffen the proximal end of the muscle, 100% of the pec activity is expressed on the discal side of the shoulder. In other words, it brings their arm around at a higher velocity. Because a hundred percent of the velocity is on the arm, the ribcage is being prevented from moving. So now we’re getting into real stabilization mechanics.

The more we can stiffen and prevent movement in the core during rapid explosive shoulder and hip movements, it means the legs and the arms move faster. So when she super drives that stiffening mechanism through that yelling, just as she’s letting air out, we’ve measured this, it creates a super stiffness in her core and higher arm velocity. She puts a few more miles an hour on her serve. So that is a form of power breathing and it’s this form of super stiffness that she’s able to create in the core – as many athletes do. When you get into carrying heavy load, whether you’re doing a farmer’s carry, a suitcase walk, a deadlift, we can then get into where you fill the lungs to about 70 or 80 percent of full tide and then you lock it down. You make it very stiff. Then you can use your hips to lever the stiff crane and pull a load, lift the load, creating a very rigid derrick through your upper body and the hips then become the prime movers of that lift. When you measure the great lifters and I have, that’s the mechanics of what they’re doing. And breathing or not breathing shall we say, is very very important. Then what they do is they sip the air.

So if you look at an Olympic lifter for example, on a clean and jerk, they perform the clean and if they let the air out of their lungs and breathe, chances are their spine would collapse. They’re that close to a braking mechanism. They’ll sip the air, they’re holding the bar and the clean. If the listenership gets what it is I was just doing, a very small volume sipping the air. Then they time that last sip with the explosive thrust through a stiff core, driving the bar upwards for the jerk part of the lift. Now having said all of that, we then get into the martial arts. And the fighting skills and we could start that off with a kettlebell swing. Where the kettlebell is swung and as it comes through top dead center, at the top of the swing, the spine actually undergoes an odd combination of compression and shear and there’s some people where they don’t like that. It tweaks their back a little bit. Other people will say that it’s very therapeutic for their back.

If you watch someone like Pavel Tsatsouline, who is an absolute freak – he really is a master with a lot of these kettle bell techniques. And he’s a superb lifter. He power breaths. So he swings the bell up and breaths, if you know what I mean.

Bret: It’s a hissing sound.

Stu McGill: It is. What that does is, once again it’s another form of super stiffening his core. Which does several things: It accentuates the hip drive on one hand, but if you can then learn that power breathing and apply it to a combative match where you’re striking with leg strikes and hand strikes. You’ll hear the fighters do the same hiss and guttural effusions, which is super stiffening the core and then they release the air, the arm is increasing velocity as the fist is increasing closing velocity to the target.

Then once again, when the fist strikes the opponent, their body becomes super stiff again. So they’re not hitting the person with the weight of their foot or their fist, they’ve actually got their whole body in a stone like fashion behind the fist. Which is called creating effective mass.

So if you’re a 172 pound welterweight in the UFC, you’re hitting your opponent with 172 pounds of that stiffened fist. So I’ve measured all of these things. Certainly not the corrective breathing as you were describing – the diaphragmatic breathing – I don’t know anything about that. But I know a little bit about super charging performance with appropriate breathing. I’ve given you 4 or 5 different examples that were all slightly different.

Bret: Well just some things you’ve touched on. I remember reading in Zatsiorsky ‘s Science and Practice of Strength Training where he recommends holding 70 to 85% of tidal volume. That’s the sweet spot for optimizing performance. It was good to hear you use the same percentages.

Then when you talked about Pavel, he and I have had some interesting conversations through email. I’ve never met him in person. I hope to eventually. I have a ton of respect for him and his attention to detail with exercises. Even the plank and things like that or the things he can do with that. I never thought of a plank before I started reading his stuff and realizing all the different things you could do to kind of create increased joint moments just through using the floor as resistance.

Anyway, let’s move on to the next topic. We talked briefly about head and neck position during deadlifts and you mentioned that you feel that it’s optimal to kind of look up and I told you that it’s kind of a controversy in our field that we should be packing the neck. Now I did research on this topic and I found that you’re never the strongest in neutral and you’re not delivering the most neural drive. Now the research is limited. We don’t have research on deadlifts but there is research on gripping and isometric curls and things like that. But when you do a grip, you get the strongest strength – the strongest MVC torque, when your head is turned the opposite way of the hand that’s gripping and when doing a curl it’s looking up. I have studied a lot of the strongest lifters and I think it’s very individual. Some guys look down, some look up. What are your thoughts on this? Are there reflexes that could be initiated? I know that Mel Siff might have written something about looking up creates an extensor reflex with the posture chain muscles. I’ve never seen that in the research though. Do you have any opinions on neck and head position with different exercises?

Stu McGill: Yeah. I do Bret. I wish you could see me because I’m just laughing to myself here. We just met and I had heard things about you because people would come up to me and say, “What do you think about Contreras because he said this?” Either supporting something you said or against it. I really didn’t know what to think but what is uncanny in this was that your little explanation there was just exactly the way I would have thought. I’ve heard these dogmatic positions on the best neck position for lifting. I’ve measured the neck position in some elite performers and you hit the nail on the head. They are all different and we get back to that it depends answer.

So as soon as you believe in the dogma that it’s always one way or another, you will help a few people. You will be good with them. But you won’t be so good with some others. The trick of it all, the magic happens when you realize that there are different mechanisms and a lot of variables. I’m not so sure what those variables are. I suspect that in lifting, the lifting musculature starts with the trapezium hanging from the neck. You’ll see some big necks and you’ll see some people who have very long necks. Others who have very short necks. How they position their neck and the style of the pull and how the architecture of trapezius all hangs from their neck. It really is gonna depend on their own personal architecture. So that’s my first reaction to that.

But the second one is, we don’t really talk too much about our current work in progress but I’m working with one of my colleagues in Europe right now. As we speak, he’s measuring nerve conduction velocity and muscle performance in the back – the back extensors as a function of different head positions. Now what those head positions do is put a pre-stress on the neural track. When you tension a nerve, it thins out. It necks down and bends out, which changes its nerve propagation velocity and ability to conduct volume. You follow what I mean with that.

Bret: Is that when you put it on stretch.

Stu McGill: Yeah, exactly. When you put a nerve on stretch, it changes its ability to carry the amount of signal and the speed at which it carries it at. I don’t know where but he’s shown me some of the preliminary data and I can tell you that we’re gonna have a really interesting story to tell because the head position determines the performance out of your back muscles. So it isn’t always one and not always the other, there are some variables that the true expert will come to understand. That’s why we all see a variety. Look, if you’re Andy Bolton and you’re lifting, you’ve gotta figure that Andy’s figured out his neck position for him pretty well.

Bret: Yup, exactly.

Stu McGill: You know? He’s a very methodical guy. He has tweaked and tuned every tiny little element and that’s why he’s so good at what he does. Is his neck position the same as another person who has a different architecture? The answer is of course not. It’s different.

Bret: That’s interesting. Is this research that you’re doing overseas, is it with stoop lifting, dead lifting, or is it with different things. Because there’s been no research on this. This will be the first research that I’ve seen.

Stu McGill: I’m not gonna give away too much more at this time if you don’t mind, Bret.

Bret: I don’t mind at all. I understand. But what you mentioned – that’s what’s so nice when you actually – because it’s so easy to just make theories. When you actually work in a laboratory with EMG, force plates, and all of these – you’ve got a lot more to go by. Speaking of, I would love to have your lab. Maybe you can leave it to me in your will?

Stu McGill: You can arrange for my demise.

Bret: No. Better be careful about that. Anyways, when you measure the different variables, you see – you know, with EMG you see such – research tends to report averages. I like how in a couple of your papers Stu, you’ll break out and kind of say this person did this, that’s one thing I love about your research. You’ll talk about well this strongman did this or Pavel, when he was swinging the kettlebell did this. He was able to activate this. I don’t see that very often. Usually all you see is the averages. That doesn’t tell the whole story because 2 of the 10 people might do better with this technique but the average shows differently so that’s, again what we’re talking about, the power of the case study. At the end of the day, you’ve got to find out what works best for the individual.

Stu McGill: Again, you’ve hit the nail on the head. If I could just make a brief comment on that because I do tend to turn heads every now and then. When I hear people criticize a study because it didn’t find statistical significance. On average there was no difference. Yet, they’ll leave the paper and walk away. You and I don’t do that. We will then go into the data and then we find low and behold, forty percent of the people had a positive effect of the intervention. 40% had a negative effect. The remaining 20% it made no damn bit difference. But 40% of those people were affected positively. What were the features of those people that it affected? Now we’re really getting into the nity gritty. That’s another key point. I love studies that on average, are statistically insignificant. I wanna know about the outliers.

Bret: Amen. Okay I know I said this but a couple more things and then we’ll be done. In the world of pain research, there – at one point I was purely all biomechanics and pain. You know, someone’s hurting, there’s a biomechanical reason for that. I need to fix it. Then I got exposed to these very bright individuals who studied pain and got exposed to the biopsychosocial model. I learned about things like the neuromatrix. The neuromatrix was fascinating to me. Talking about phantom limbs and how these people are still experiencing pain even though their limb has been amputated. Your brain has a mental map, a neuromatrix if you will. Your brain’s depiction of the body is not the actual body. These things are all important to know about pain.

However, when I help people – when I’ve tried to fix people. Again, I’m not a physical therapist but hell, everyone – you take the average client and they have some aches and pains and things that don’t feel so good. They also can – when you start getting them stronger – things arise. I always take a biomechanical approach to that. I don’t say to them, “Okay. You’re depressed. I’m gonna try to cheer you up.” I always use a biomechanical approach and I know that’s been the crux of your career. I guess my question is, do you keep this stuff in the back of your mind when you work with people and kind of realize that if you look at the research there is not a lot of research showing that anterior pelvic tilt increases the incidence of back pain? Or that people’s biomechanics really on average it does not lead to pain. But when you work with people, and you – like what you said – you provoke their pain. Usually you can find things that hurt it. Then you get them to avoid that and you get them to move in a way that’s not painful and then you gradually increase their fitness and build on those patterns. The biomechanics would say you are improving; you are decreasing their mechanical insults. You are improving their function, biomechanics, and decreasing pain.

Whereas, the pain scientist or biopsychosocial model might explain it differently. They might say that you have these neurotags and you’re having these threat responses. Through doing the new movement you are decreasing that threat response. You’re teaching the body to move in a different way and accept it. They’re working with a high level coach or trainer in your case, the world’s leading spinal biomechanics. They are comfortable. They are confident. So that’s gonna really affect the results of their recovery because they’re so confident with you. They’re expecting results. So it’s kinda like the placebo effect in a way. Is it important to know both sides or are you a pure biomechanics guy? Talk about that a little bit.

Stu McGill: I don’t think I’m a pure anything. It’s important to be as knowledgeable as you possibly can to explore alternate possibilities. Alternate explanations for what you’re observing. I could give you case after case where traditional pure biomechanical thought couldn’t give an explanation for what you’re seeing in front of you in a patient or athlete. Having said that, let me just take the other side and then I’ll come back to this. There are those who say, “Oh for pain, we’re going to teach them to live with their pain, to handle their pain. We’re gonna tell them that the pain is mostly in their head. It’s a perception and we’re gonna modulate their brain to handle their pain.” This is where I really start to disagree. If you can do provocative testing and cause their pain to get worse by putting them in an awkward posture or stressing the pain somehow. If they say, “Oh yeah. That hurts more.” You’ve just proven that it’s a mechanical variable that makes their pain worse and probably if you can take that mechanical insult away, the pain will be less and hopefully even disappear.

This is a rather harsh opinion, but those who are real proponents of all this psychosocial, they are very poor with their mechanical of understanding. Their mechanical understanding of the phenomenon. So it becomes a default diagnosis. By default, we can’t find the pain in you. Our interventions don’t work on you. It’s not that we’re bad doctors, it’s that you’re a bad patient. The pain is in your head. So it’s a default diagnosis and therefore, the patient should have physiological counseling. That’s what I really get ann