Most people have heard about the ‘core’. Perhaps you’ve been told a stong ‘core’ will prevent you from getting a bad back, maybe recover from one or improve sporting performance.
A whole way of training has developed from this theory that you need to do ‘core’ exercises or you need to activate your ‘core’ before performing an exercise. I used to be believe in the technique called ‘bracing’ (Prof Stuart McGill) before lifting weights. Bracing is where you contract you abdominals as if you were to receive a blow to the stomach. This increases the pressure in the abdominal cavity and stiffens the spine. During my back course I started to see that perhaps the technique where you draw in belly button in, called ‘drawing in’, was a better technique to activate the muscles of the trunk. The evidence for this technique came from a trainer named Paul Chek.
It was first proposed in the 1990′s when studies that showed a muscle called the transverse abdominus (TvA) contracted more slowly in people with back pain compared to those who didn’t. The conclusion drawn from this was that back pain was somehow a result of slow contraction of the TvA. N.B. slow contraction, not strength.
In my opinion, it has snow balled from here with help from Paul Chek and his studies. Physiotherapist, Osteopaths and Personal Trainers have taken on the ‘drawing in’ technique for rehabilitation exercises or when exercising in general
Now, during my course in ‘Management of Lower back Pain’ we were given another article by Prof. Eyal Lederman called ‘The Myth of Core Stability’. It goes against the grain of popular thinking (a bit like me) but it made a lot more sense to me than the other two techniques
The article is too in depth to fully cover here, but I will try and get across the main points that stuck in my mind and changed it. Please feel free to read the article for yourself.
One of the first things Prof. Lederman looked at was the studies in the 1990′s. One of the things he suggests is that the reason why the TvA contracted slower was a protective mechanism. Much like the change in movement when you pull away from a hot plate but you have injured shoulder. Your movement is different to protect the shoulder from further potential injury and pain. It is a reflex that you don’t control and would find very difficult to change the movement pattern. This makes re-setting the TvA by ‘drawing in’ unlikely He also highlighted that there was no decrease in the strength of the contraction. It surprised me to learn that to stabilise the spine only a faction (about 2%) of the total force from the trunk muscles is need. Only 3% when 32kg of weights is added!
Another point Prof. Lederman makes is that movement is not a conscious process. If you lift your hand to your mouth you don’t think of what muscle to contract, in what order and how much. This is exactly the same with your ‘core’ and movement. Your muscles will work differently when lying down, sitting down and standing up. So, ‘core’ activation will be different lying down to when standing up. A lot of ‘core’ work is done lying down or on a Stability Ball. How can this translate to everyday or sporting activities? Even doing fast arm circles will activate the trunk muscles differently to performing slow ones. Rotational movement causes different parts of the TvA to contract at different points of the movement. How does someone consciously control those differences just by ‘drawing in’?
The other point is strength. How do you judge consciously how much you are contracting a muscle? Do you know what 50% of trunk muscle contraction feels like, let alone 2% or 5%. If you are told to strengthen your TvA the contraction level you can produce by ‘drawing in’ isn’t enough to produce a strength adaptation. Anyway, you need to lose a lot of strength in your TvA to need to strengthen it!
Lastly, a table of studies in Prof. Lederman’s paper shows that compared to general exercise (the general exercises aren’t specified) ‘core’ exercises are no more beneficial. It then comes down to choice of what you prefer to do so that you stick to your exercise programme.
So the question now is what was the point of the course I went on if general exercise is all you need to do? Well, I think a lot of injuries of the back or other areas of the body are due to muscle imbalances and muscular strength, not necessarily posture (another of Prof Lederman’s papers), and range of motion around the joints. Back pain could be down to restricted movement or too much movement around the hip joint, for example. Even ankle mobility can cause back problems! I also think that when performing exercises it is better to focus on body awareness and alignment, especially when tired, and move the body part accordingly.
Your body knows only movement not muscles.
Chris Hall is the At Home Fitness Personal Trainer in south London. He is a level four back specialist Personal Trainer.