An interview with Stuart McGill07/18/03
As a T-mag reader you might be asking yourself, why should I care about my back? I'll tell you why: How do you plan to get huge and lean for the summer when you're laid up on the couch getting in touch with your "All My Children" side, unable to train thanks to a nasty back injury?
If you want to avoid injuries; if you want to learn the myths about stretching the spine and the truth about the lower vs. upper abs question; if you want to know why good-mornings may not be the best thing to do if you want a good morning; if you're sick of insulting nonsense like "keep your back straight when lifting" and want to learn about the back in a more sophisticated way that actually applies to your training, then I suggest you read on and listen to what Stuart McGill has to say.
He's going to tell you how a lot of training principles simply don't carry over to the spine and that there's a subtle difference between what builds us up and what tears us down. Stuart McGill is one of the world's best when it comes to understanding the back and spine. In short, he gets bad backs back in business.
You're probably still wondering just who this McGill guy is. Stuart McGill, PhD, is a professor at the University of Waterloo in Ontario, Canada, and an internationally recognized lecturer and expert in spine function and injury prevention and rehabilitation.
His labs have produced more than 200 scientific publications that address lumbar function, low back injury mechanisms, mechanisms of injury prevention and rehabilitation and, most recently, issues related to high performance. As a consultant, he has provided expertise on assessment and reduction of the risk of low back injury–along with rehab approaches–to government agencies, corporations, legal firms, professional athletes and teams, and is regularly referred patients for consultation.
Put simply, this guy knows his stuff!
T-MAG: What motivated you to get your PhD in biomechanics of the spine?
Stuart McGill: There was no specific motivation – only fate. I was thinking about going to the University of Waterloo to do my PhD in systems-design engineering and happened to meet a professor while playing hockey named Bob Norman, a professor of biomechanics. After getting to know him I decided to switch over to his lab and began my PhD studies under his mentorship. At the time he was asked to be an expert witness for a significant human rights case involving the hiring of women and the risk of back injury, and he asked me to develop some software to compute the loads on people's backs.
At that stage I didn't know the difference between a bad back and a bad front! His advice was to go to the anatomy laboratory to get a sense for the architecture and what I quickly realized was that the structure of the back–the bones, muscles, ligaments– was nothing like what was available at the time in biomechanical models. I was beginning to suspect that many of the conclusions from these simplified models were silly– at least for understanding how the back works, determining the risk of injury, and for providing evidence for higher performance.
So my PhD research focussed on developing methods that would quantify the force distribution in the muscles acting in the back–I wanted the most sophisticated and anatomically robust program with a very high degree of biological reality to show me how people's backs really worked. So, that's how it started; eventually I became a professor, expanded the lab to do spine tissue work, and our team has just kept growing.
The final interesting part of the story is that physicians and coaches somehow heard about our work and began sending various personalities from the sports world and the business world to our lab. It became a real eye-opener to see that many of the top athletes were having chronic back troubles because of ill-chosen training approaches. So I never set out to get a PhD in spine biomechanics. The whole story is just dumb luck really! But looking back I wouldn't trade it for anything.
T: As part of your job you get to supervise graduate students. Currently the head MD for the Toronto Raptors, Dr. Doug Richards, is completing his PhD under your supervision; he must add to your wealth of knowledge, not to mention others you have worked with over the years?
SM: Sure, Dr. Richards is a first class physician; he has wonderful insights into both rehab and training for performance, and we learn from each other. Currently my PhD students include a physician, a physical therapist, a chiropractor, a clinical kinesiologist and personal trainer together with some engineering expertise, so it's a fantastic group to coordinate and tackle each issue.
And I'm very proud of my former students. A lot of them have gone on to be quite influential. I think of Dr. Cholewicki, now a professor at Yale's medical school: whom I consider to be the top spine stability scientist in the world. He was an Eastern European classically trained lifter when he came to Canada from Poland, and, I wouldn't be surprised if he still holds a few Canadian records in his weight class. Here's an example of an individual who has been there, knows the issues, and has the academic training to really be authoritative. There are many other former students I would like to brag about... (Eyes glaze slightly–he smiles.)
T: When I think of a guy who has his PhD in biomechanics, I think of a pencil-neck who has never seen a barbell in his life and spends all day in the lab playing with rats and numbers. Are you this geek I'm thinking of or are you a scientist that actually works with athletes and other "real" people?
SM: As you know, in my younger days I played football and loved to work out, but I was typical in that we were never exposed to scientific methods beyond the basic body building approaches. So I've been there as an uninformed athlete trying to train. Now, every piece of research that we produce must make a contribution! My job as a spine biomechanist is, first: to figure out how the spine works and how people become injured, and second: to use this insight as the evidence base for developing justifiable prevention approaches. The third part is to develop better rehab and performance training. I'm here to solve real problems. We roll up our sleeves and try to get to the real issue.
T: Did you learn about the back solely through your own and others' research, or did you educate yourself by other means?
SM: Of course we perform a lot of creative research to try and obtain novel insight. But I have also learned a lot from others. About 15 years ago I started to get invitations to various medical and therapy schools. I met some very influential people like Dr. Vladimir Janda, who taught me a lot on how to assess different kinds of movement disorders and syndromes. There were many, many others too–manual clinicians like Dick Erhart and Craig Leibenson, orthopods like Harry Farfan, and some of the athletic gurus like Mel Siff.
And in the last few years I have been meeting some of the "strongman" and celebrity athlete personalities at some of the fitness conferences I have spoken at. All were characters and had made valuable contributions, but I didn't always agree with them. At least it gave us a different perspective on things, and hopefully a deeper insight. That really helped in my education because I was exposed to all these different kinds of approaches, not solely thinking as a biomechanist. I don't even know how I would classify myself now! But the important thing was to have frank discussions, sometimes brutal arguments–but we always went for a beer afterwards.
Every time I go to a medical school, university, or clinic, every time I work with an athletic team, I have to admit I learn a lot, even from the people I'm supposed to be teaching. I never know when I'm the student or the professor. So to answer your question, my real education has come from directing the lab work in combination with my working with other clinicians and scientists, my graduate students, and patients, workers and athletes.
Let me give you a final illustration–if you want to find out how to build supreme strength, you will be disappointed reading the scientific literature because it may present a single perspective on some unidimensional issue. But then go and talk to a legend who's done it like Bill Kazmeier who can give you a very eloquent and insightful viewpoint, integrating aspects of technique, training issues, and nutrition. Very few professors would bother to seek out such a fantastic knowledge base so they stay several years behind what the creative minds are putting into practice. The real creativity rarely comes from the PhD's in this area. I don't have many opinions, do I? (Laughs.)
T: Are professional athletic teams and basket-case bad backs regularly referred to you?
SM: Yes, I'm not a physician or licensed to practice medicine, but as you know people and organizations from all over the world ask me to consult with them. When I give my lectures I show the science and how it's applied to real people–people relate to that. Around 15 years ago physicians began to ask me to consult on specific cases and I'd be asked to be an expert witness in legal cases involving the back. Slowly, through word of mouth and experience I suppose, I became this consultant. I don't see the average bad back. A lot of times, I am asked to consult on the tricky, difficult-case bad backs; other times it may be a medical management team that would request consultation, or perhaps a player, or a lawyer–sometimes they fly them up here or sometimes they fly me out to them.
T: What professional teams or sports have you consulted for regularly?
SM: First, much of what I do is confidential–you can imagine an athlete whose worth would be compromised if the world knew they had a bad back. So you'll just have to ask around...I cannot name names. Nor would I say that I consult with them regularly. I'm brought in to give an educational session or an update on the latest progress in science or perhaps to help an individual. But you know it's funny–there are some consultants and gurus in training and athletics who are often quite ahead of the science. Sometimes they have also consulted with the organization already...before I am asked to consult.
When I am brought in, I may be able to confirm what they have suspected or blow it out of the water. Sometimes they're just barking up the wrong tree and may have made suggestions that are detrimental to back health. But a lot of the creativity is from the athletes themselves; they really push the envelope. At that point a back geek like myself may be able to confirm things and enhance some aspects and make them safer and a lot better, producing better results. But I don't consult regularly for any one team; I come in to set up a program and perhaps deliver some education. I like to have a patient's care-provider or, in the case of an elite athlete, their strength and conditioning coach attend the consultation, so it also becomes a matter of training their trainer and then I turn it over to them. But part of my role as a professor is to keep monitoring to see how I've helped...or in some cases failed!
T: Most weight-training regiments involve working the joints through a full range of motion. You claim the spine is different. Can you explain this?
SM: Yes...from several perspectives. When you look at the mechanisms of injury–let's take for example a herniated disk–if a person maintains a neutral spine, as would an Olympic weight lifter for example, it's very difficult to create a herniated disk. In contrast, in powerlifting some of the folks repeatedly flex their spine, and repeated full flexion with spinal compression is the mechanism to create a herniated disk.
Here is an example of where a muscle physiologist might tell you "Yes, you've got to work the spine through a full range of motion," but if you do it under load you risk replicating the disk herniating mechanism. So the training becomes a damaging routine accumulating microtrauma rather than continuous tissue enhancement and improved performance motor patterning.
Another vital fact is that under pure compression loads, and when the spine is fully flexed, we've measured the spine losing up to 40% of its ability to bear compressive loads. In other words the spine is strongest when in a neutral position.
Also among the misperceptions that I hear out there about the rectus abdominis, and upper vs. lower abdominals, is that you've got to work the rectus throughout its range of motion. Again these might be muscle physiologists speaking but not people who are cognizant of spinal mechanics. For example, when you look at the architecture of the rectus, it's a muscle with four heads, four contractile components each separated by a lateral tendon.
If it was a muscle designed to work through its full range of motion it would be one long continuous muscle–but it's not. It anchors the obliques and transmits the hoop stresses laterally through those lateral tendons. If it wasn't beaded, the oblique forces would rip it apart laterally. In many elite performances the abdominals contract isometrically. Too many bad backs are created by misinformed people thinking they need to train the rectus with repeated full flexion exercises. There are much better and safer ways to do this.
So again if we're training athletes to perform, the question is do they need to work the lumbar spine through a full range of motion? Lumbar flexibility often increases the risk of future chronicity! For example, I've worked with some very good discus throwers and you'd think that discus throwing would require a huge amount of twist in someone's back. In fact, if you take the twist out of the training, stabilize and lock the ribcage onto the pelvis, and twist through the legs and shoulders, you may actually enhance performance. Certainly it may be required to reduce back symptoms.
Other performance requirements include variables like speed, agility and/or strength for example; all three of these things require stability, perhaps keeping a line of drive down the torso and through the feet into the ground, etc. A stiffened core may be optimal. So, of course this whole issue depends on the person and the task. But in many cases from both performance and safety perspectives, it's a bit of a myth that the spine needs to be trained through its range of motion.
T: I think most T-men are not rounding our backs during squats and deadlifts. However, you've said that I should not stretch my back like it would be stretched when I bend over to touch my toes in a hamstring stretch?
SM: First, there are many backs that should not be stretched–those with discogenic pain may perceive the sensations from stretching muscle spindles as good, but they will be fooled–the disks may be accumulating trauma to ensure they remain chronic.
Second, I would consider that a very unwise way to stretch your hamstrings. A much more clever way to stretch your hamstrings would be to stand upright, put your leg up in front of you on a stool or box and have the spine in a neutral posture while rotating the pelvis to stretch the hamstrings. But be careful and ask the question yourself why you're stretching the hamstrings. You may be compromising knee stability.
T: So you're saying that there's not much point in stretching the ligaments of the spine?
SM: Again, stretching ligaments in the spine is a myth. If you stretch them to create an increased range of motion, you're going to either tear them or avulse them. You may be building your tolerance to stretch–or you may be stretching muscle. But you don't want to stretch ligaments; they're there for a reason. They're there to protect the discs. But don't get me wrong, I'm not saying don't warm-up.
Also, remember that treating someone for health objectives vs. training them for performance are two different ball-games. We have measured world-class powerlifters, and even though they appear to fully flex their spines, they in fact don't. But at the end of the day I'm not saying never flex the spine, either. There is a time and a place.
T: "Never" is a powerful word.
SM: It is, absolutely! People take me too literally and out of context sometimes because I may be giving a lecture on getting bad backs better which is an entirely different philosophy from training for ultimate performance. Take the issue of breathing: we work very long and hard on establishing breathing patterns where people can still maintain spine stability. So if you're a hockey player, or football player, we're training motor patterns overlaying breathing, balance, agility and all those kinds of things.
On the other hand, if you're taking a sprinter or powerlifter who does not breathe–they may inspire deeply, hold the breath, and bear down and may just sip the air, but no breathing. So we use the word "never," but it is within a specific context. Ultimate performance, and super strength and power as a lifter is an entirely different world of training from training for the NBA, for example– or to minimize back pathology so that rigorous training can be resumed.
T: So I guess slouching while sitting during rest periods would be a bad thing?
SM: Totally, that would be very detrimental. We first noticed this after doing several experiments showing that the spine becomes weaker if you sit flexed for a while. The tissues creep and have a bit of a set to them and take quite a few minutes to restore their normal biomechanics and proprioceptive functioning even after standing up.
So it is not wise to sit slouched prior to a lift and we correlate that to prevention of back disorders in ambulance drivers, for example. They're athletes: look what they have to do, sit in a chair slouched and vibrated while driving to the scene where they lift a 300-pound patient out of a bathtub; that is an athletic lift, there's no question. So the prophylactic preparation would be to sit upright–have a pronounced lumbar support in the ambulance. But for a lifter to sit slouched that would be very detrimental. We showed the unfavorable effects in athletes who sit on the bench and then have to play, particularly the 7 foot NBA players sitting in chairs with their knees in their ears. That's asking for a back injury, it's crazy!
T: You also talk about abdominal-bracing during most movements. What do you mean by that exactly?
SM: The spine under compressive load will buckle under very low loads and you need muscles to stabilize it–bracing does this. People have used the analogy of guide wires on a ship's mast–it's very apt–to prevent unstable behavior.
You may have heard about transverse abdominus and multifidus as being very important stabilizers of the spine. I'm afraid that if that's what's being used to create stability you won't create much stability at all–you need all the muscles. Not only will the spine buckle, but it can become unstable in shear. The criss-crossing action of the obliques, for example, anchored on rectus abdominus, means that you have to not only fire up transverse but also the obliques and also rectus.
An abdominal brace is where you tense all the abdominal muscles, but you do not suck the navel towards the spine. You can once again use the analogy of the rigging of a ship's mast–if you move the rigging closer to the mast it actually buckles at a lower load, and if you can move the guide wires out away from the mast you get much more stability. The classic weight lifters like Vasily Alexiev didn't have a nice hollowed abdomen–in fact he had enormous stability that came from the distances of those strong guide wires, to give a graphic example.
So don't solely focus on multifidus, but I'm not saying neglect it either; I'm saying think of it with all the other extensors in mind. People don't give credit to muscles like latissimus dorsi, which is very rarely mentioned in spine stability yet supremely important. Every muscle we have is important at some point in time or in some situation.
T: I know some practitioners who talk about tummy sucking to activate the transverse; is that a form of bracing?
SM: Well it was originally conceived as a form of reprogramming perturbed motor patterns of the transverse abdominus. Whether it actually reprograms transverse is debatable. But it's certainly misdirected effort if you're trying to stabilize the spine. You have to do much more than just activate transverse. You need all the muscles, and you do the brace not to suck in but to activate all those muscles to create the brace to protect the spine so it won't buckle or shear in an unstable way.
T: I understand you don't like sit-ups in their most popular form.
SM: So many athletes come to us with bad backs and I ask them about their current routine, and they might tell me, "Well, I do 100 sit-ups first thing in the morning." Sit-ups cause far too much spine load for the associated muscle challenge that is created, so the trick is to find an appropriate muscle challenge level that's appropriate for that particular athlete.
You probably want the spine in a neutral posture, but sit-ups involve full spine flexion, which is a problem for many people as well, so in this case we do a modified curl-up to achieve the same if not more co-contraction of the abdominals, obliques and rectus. We ab brace first, elbows off the floor, good neck pattern, then curl-up against the brace just a little bit, not rising very much; then overlay deep breathing patterns. An incredible ab workout that spares the spine.
It also creates motor patterns that you can use in real life, whether you're playing football, powerlifting, sprinting, or whatever it is you're doing to ensure spine stability, and a large ability to buttress shearing and bending loads, and breathe functionally, etc.
T: What if muscle hypertrophy is the goal? Will isometric contractions facilitate this? Assuming my body-fat percentage is low enough to reveal a six-pack, I'm concerned with the visual impact of my abdominals in addition to their functional capabilities. Is there much room for hypertrophy to take place or are we limited in the extent to which we can get our abs to grow?
SM: I'm not worried about that, Marc, six-packs are for beer and I prefer two-fours! (Laughs.) But really that's not my world. If you want to hypertrophy those muscles there are much better experts than I. But if you want to perform and enhance health, you have my attention.
I don't think bodybuilders and people worried about aesthetics want big bulky obliques. How much you can hypertrophy the obliques is another question; certainly with rectus you can "look ripped" if that's what you want to do. I can design one hell of an abdominal workout without doing any sit-ups. First you have to dispel the myth about upper and lower rectus, but there are absolutely neuro-muscular compartments in the obliques – anterior, upper, lower, medial, posterior – and you have to do many different things to train them effectively. A simple sit-up with a twist is not going to cut it. So, I'm thinking more about function.
Part 2 of this interview will adress the proper elements of ab training, how to brace for heavy lifts, and common mistake made by trainers and trainees alike. Look for it in the next issue of T-mag.