I was fortunate enough to have a 30 minute conversation with Dr. Staurt McGill and ask him a few questions related to back health and core conditioning. I have posted the questions and a summary of Dr. McGill’s responses below.
I have featured one of Dr. McGill’s recommended core exercises in a previous post entitled “Core Exercise Series – The Bird Dog“.
This information from the interview will benefit personal trainers, exercise therapists, athletes, office workers and people who generally want to improve their back health / core.
I would like to take this opportunity to thank Dr. McGill for his time and expertise.
Dr. McGill testing a professional “Strong Man” competitor – Image Source
About Dr. Stuart McGill
Dr. Stuart McGill is a Professor of Spine Biomechanics at the University of Waterloo where his laboratory explores low back mechanics of both uninjured and injured people. His advice is often sought by governments, corporations, legal experts and elite athletes and sports teams from around the world.
Dr. McGill has written two books and greater than 170 journal papers. The links to Dr. McGill’s books are provided below.
Healthynomics: People often consider the “core” to be the abs. Can you explain why this approach to core conditioning is flawed?
Summary of Dr. McGill’s response:
When you consider performance enhancement, the hips are the centre of power production. But for hips to create power, the torso needs to be stiffened. Take for example a rugby player making a cut planting one leg in order to change directions. If the player’s hip on his/her non-supporting leg (the non-planting leg) drops, there will be a loss of energy which has “leaked” out due to the lack of torso stiffness created.
To stop this energy leak from occurring, one must consider training muscles like quadratus lumborum, latusimus dorsi and the full erector spinae. These muscles together work to create this stiffness and permit the hips to generate more power. If you can fixate the core, it will unleash the power in the hips to optimize performance.
This mechanism also can help protect the back. If the spine is stiffened in a neutral position, the most resilient position for the spine, it will be able to withstand much more loading than when in a deviated posture.
HN: In today’s society, people are sitting more than ever. What advice can you provide with regards to work stations and prolonged sitting? Do you recommend sitting on Swiss Balls or integrating standing work stations?
Whether it’s looking down at their cell phones or slumped over a computer all day people are constantly flexing their spine. This constant flexion initiates damage in the annulus of the disc (outer wall of the intervertebral disc).
As the spine is not a ball and socket (i.e. it is more like a flexible beam that has a limited number of bends before it cracks), one cannot treat it like a ball and socket joint. Prolonged flexion of the spine will eventually cause cumulative stresses to delaminate the collagen fibres of the disc annulus and bulging and pain will occur.
Low back pillows or lumbar supports help position spine back into its most resilient (neutral) posture. Additionally, using a lumbar support can create training capacity by preserving the natural curve in the spine when seated so that less pain is experienced during subsequent therapeutic exercise sessions.
Take for example, someone driving 45 minutes to a sports training session. In that time in the car, the individual has created some of the stresses from change in geometry of the nucleus inside the disc and creates pressures within the annulus. We have measured these and it takes time for the stresses to resolve (and occasionally they do not resolve). But preserving that natural curve with a lower back support / pillow prevents the damaging stresses and thus can build and facilitate training capacity.
Swiss balls and standing work stations are utilized in attempt to avoid prolonged flexion. Both can provide help for some people.
With the Swiss ball however, you will use lot more muscle activity to maintain your posture, but the natural back curve is generally maintained. So Swiss ball sitting tends to wear people out and sitting will no longer be a relaxing activity. If using a Swiss ball to sit, Dr. McGill recommends starting with 10 minutes and alternating between the Swiss ball and a chair. The caveat is to take care to not roll off the ball – there have been reports of quite substantial injuries resulting from these incidents.
Sit/stand stations will help people with disc bulges and these individuals often find relief by the frequent posture change in a standing sit/stand workstation. Interestingly many posterior disc bulges are able to withstand higher compressive loads as long as the discs are not bent into a sitting posture.
HN: In your research and previous interviews, I have heard you say that “spinal discs only have so many numbers of bends before they damage”. What does this mean it relates to back health?
Dr. McGill started with an example of a metal wire that you need to break. In order to break the wire, bend the metal at one spot, back and forth until it fatigues. Eventually, the metal will become so weak that it breaks. In engineering terms, you have essentially repeated stress/strain reversals.
This example applies to our spine in that our spinal discs are not ball in sockets you can consider them to be more like the wire. If you were to do sit-ups over and over, repeatedly bending the spine you will fatigue the weakest link or a particular disc and eventually lead to spinal injury.
With all this said, it does not mean that you cannot move your back at all. What one needs to understand however, is that with high loads on your spine, there is a higher chance of injury when the spines moves lifting or carrying the heavy load. With a light load on your spine, you are far less likely to injure yourself with movement through your spine and movement is much better tolerated. In fact the way to move the back for those wishing to create some mobility but who have pain, kneel and get on the hands and knees – flex and extend the spine. This minimizes the applied loads and reduces the risk of further bending stress. Only 7-8 cycles are usually needed.
HN: What are the latest techniques for training the backs of athletes?
With regards to the spine itself, there is nothing new in that the spine doesn’t change and follows the same biomechanical/physiological and neuromuscular processes and principles. The need for therapists and trainers to match the best progressive exercises to the individual has also not changed.
Each person requires an assessment to determine what is causing their pain if they have any, eliminate the pain mechanism and build on the variables that need to be addressed (e.g. maybe they need more hip mobility to spare their back, maybe they are too strong in back and need more endurance so they don’t break form when fatigued). These are universal principles that all good trainers and therapists should adhere to – nothing has changed here.
Dr. McGill measured the muscle activation profiles of “world strong men” and saw the importance of shoring up weak links. This principle applies to all sporting activities. Consider when you carry something asymmetrically (i.e. like a suitcase on one side of your body or a beer keg if you are a `strong man“) as you’re asked to stand on one leg and carry or support a load. We rarely perform such an activity in the gym, but outside on the playing field, this is often a defining strength moment. Dr. McGill would argue that this training the lateral core strength component (quadratus lumborum) is often neglected.
Another finding validated by Dr. McGill`s research involves UFC fighters. Dr. McGill discovered that UFC fighter’s ability to kick and strike quickly is not just a matter of strength but also a matter of training muscles to contract and then relax very quickly. Take for example, a UFC fighter kicking an opponent in the head. The fighter triggers a muscle pulse to initiate the kick and then relaxes to create foot speed. Next, the UFC fighter must stiffen his core again prior to contact in order to kick his opponent with great impact force.
In other words, the fighter needs to activate muscles extremely quickly and then be able to relax them to allow middle section (speed generation of the foot) of the double pulse of activation to happen. How many great trainers are training rate of muscle contraction and rate of muscle relaxation? Dr McGill suggests that very few – only the very elite, yet this defines some of the great athletes.
This also applied when Dr. McGill measured the muscle activities of great distance hitters in golf. They are not necessarily the strongest, but long distance golf hitters have this wonderful gift of creating a pulse – this on/off at the instant the club hits the golf ball.
These are two little nice discoveries that if you can get it right, you can really enhance athleticism. The top athletes in the world can steer their strength through their body linkage, eliminate the energy leaks, and can pulse muscles on and off very quickly.
HN: Are there any particular exercises that you recommend to increase spinal stability and athleticism?
UFC fighters and martial arts athletes traditionally perform thousands of sit-ups in their training. Many of them develop intolerance to flexion because of the numbers of bends they perform in these sit-ups. Their reason for performing so many sit-ups is often misunderstood. UFC fighters and martial arts athletes are looking to create a protective armour (a 6-pack of muscle) so that their internal organs are not damaged from the tremendous kicks and blows, its not only just about a strong core.
You can create this armour through sit-ups and a few lucky ones will be able to withstand this form of training, but many will eventually damage the discs. So, how do you build the armour and core strength without doing sit-ups?
Dr. McGill has found that one of the better exercises to build this armour, develop tremendous core strength and avoid potentially damaging spinal flexion is an exercise called “stir the pot”. Watch the video near the bottom of the post, which describes and demonstrates the exercise.
Dr. Stuart McGill’s books are available for purchase on his website: http://www.backfitpro.com/