If you have set foot in a gym any time this millennium, you are almost certainly familiar with the term core stability. You probably know that core training (or core strengthening), is designed to reward us with better posture, a flatter stomach and a reduced likelihood of back pain. And for athletes and sportspeople, there is also the promise of improved performance and a reduced risk of injury.
But how does it work? The theory is that the ‘core’ (which encompasses the musculature of the trunk, lumbar spine and pelvic region) provides the stable platform from which movement is generated. ‘When the system works efficiently, the result is appropriate distribution of forces, optimal control and efficient motion,’ explains Dr Michael Fredericson, a professor in orthopaedics and sports medicine at Stanford University. If, however, the core is weak, the body’s ability to exert or resist forces is compromised – making our movements less powerful and the risk of injury greater.
It sounds feasible enough, and there is evidence to back up the claims. For example, a study in the American Journal of Sports Medicine found a correlation between poor core stability and the incidence of knee injury in female athletes, while research in the Journal of Strength and Conditioning Research found that six weeks of core stability training resulted in a significant improvement in 5km time among runners.
I can add my own anecdotal evidence: I first came across core stability training 10 years ago, having spent a year plagued by knee problems. I’d changed my shoes, had orthotics fitted, rested, undergone ultrasound and numerous other treatments, but it wasn’t until I met chartered physiotherapist Sarah Connors (with whom I later co-authored the book Running Well) that I was introduced to the precise and subtle exercises of core training. Within a few months I was running pain-free and not long after I completed the 100-mile Himalayan Stage Race. I’ve never suffered from running-related injuries since then.
Connors remains a fan of core training. ‘I still prescribe core exercises when the muscles are not working correctly,’ she says. ‘A lot of the over-use injuries I see are a result of the core muscles switching off and the wrong muscles taking over, leading to biomechanical problems and overuse injuries.’
But not everyone thinks core stability training is all it’s cracked up to be. In the past few years, I’ve heard the concept criticised by everyone from physios and osteopaths to personal trainers and Alexander Technique teachers. Some argue that while it may have value for lower back pain sufferers (which is where core training originated), it isn’t necessary for everyone.
Dr Fredericson, however, believes we can all benefit from stronger core muscles, and no one more so than athletes and sports enthusiasts. ‘I have never met an athlete who wouldn’t benefit from core stability training,’ he says. ‘Even in my work with Olympic standard runners, I see evidence of core weakness.’
If we accept that core stability training is worthwhile, what kind of exercise is best? Recent research from the University of Ballarat in Australia compared trunk muscle activation during squats and deadlifts – two common weight training exercises - with activation during specific core stability exercises – the ‘superman’ (from all fours, one arm and the opposite leg are extended) and side bridge (in which the body is supported sideways on just the elbow and feet). There was no significant difference, leading the authors to conclude that performing upright dynamic exercises was just as good at activating the trunk muscles as isolated core work and, in fact, may be more useful in the real world.
‘It is true that dead lifts and squats with weights will activate the core muscles,’ responds Dr Fredericson. ‘But one needs to work in multiple directions and planes of movement to activate the many muscle groups that make up the core’.
Professor Eyal Lederman, an osteopath with a doctorate in physiotherapy, finds the idea of isolating specific muscles objectionable. ‘Since we have only one spine, any physical action or exercise will work the trunk muscles,’ he says. Earlier this year, he published a paper in the Journal of Bodywork and Movement Therapies called ‘The Myth of Core Stability.’ In it Prof Lederman quotes the sport science principle of specificity, which states that training should closely match the requirements of the sport - raising the question – when, in sport, do we lie on our backs with our legs in the air? ‘Core stability training is very different from the demands of most sporting activities,’ he says. His advice? ‘Focus on training in your favoured activity, and don’t worry about the core.’
Dr Fredericson has a different point of view. ‘If we know these exercises work for people with back pain and various other hip and knee injuries, why not encourage everyone to do them? I don’t see why we should wait for problems to occur before incorporating core training into our workout routines.’
I have to say, I agree. The research is equivocal but I can’t disregard the enormous difference it has made to my ability to sidestep injury, and run better. I am still waiting for the flat stomach, though.