Blog reader and fellow biomechanics enthusiast, Michele Morseth, sent me a GREAT link that speaks to the issues I talked about in my blog post called "Your 'core'". You have no idea how excited I am to have read this, since I was starting to think I was taking on the whole Pilates movement alone... until I found out that there are real, live experts who agree with me.
I could summarize, but every sentence is worth reading. Enjoy:
Core Stability: Abdominal Bracing vs. Abdominal Hollowing
At a recent strength and conditioning conference hosted by the British Olympic Association, top weightlifting coach and strength expert Mel Siff gave a compelling demonstration of how the abdominal hollowing manoeuvre commonly used as a core stability exercise actually makes individuals less stable when attempting to stay on their feet during contact with others.
You can demonstrate this for yourself with the help of a partner, as follows:
?Stand up facing your partner and grasp each other's hands;
?Now perform the abdominal hollowing manoeuvre by simply sucking in your navel;
?Get your partner to shove in a random way and see how you are able to resist and balance;
?Repeat the exercise but, instead of hollowing, brace your stomach muscles as if you are about to be punched. Compare the difference in stability.
You should find that by bracing you are able to resist the force and retain your balance more easily. Mel was using this demonstration to illustrate how the whole stomach musculature is involved in stability tasks against external loads and forces, especially during weightlifting. He was arguing that, in this context, abdominal hollowing would make you less stable and less strong.
It is a commonly-held belief that abdominal hollowing is the answer to core stability, encouraged by physiotherapists and Pilates trainers. Much of their core stability work focuses on exercises that isolate the tranversus abdominis muscle using the hollowing technique, with a view to stabilising the lumbar spine. In fairness to the physios, the focus on tranversus exercises stemmed from research on low back injury patients, for whom the transversus seems to lose efficiency. In this context tranversus isolation training is effective. However, fitness coaches have applied these exercises in a wider context, which Mel Siff argues is misguided. ?If you are an athlete lifting heavy loads or competing on the field in contact with other athletes, exercises lying on your back on the floor recruiting only the transversus muscle will be of little use,' he explains.
Recent research from McGill of the US supports this point of view. He has demonstrated that the abdominal bracing technique described above is more effective at stabilising the lumbar spine than abdominal hollowing. The rationale is that if the abdominal muscles are tensed by bracing, the obliques and transversus are activated together from a wider base, which gives more effective support. If the stomach is sucked inwards, as with hollowing, the obliques are less active, which reduces the lateral stability, and the tranversus muscle is shorter and thus able to produce less tension.
The key message is this: unless you have a back injury, do not perform isolation transversus exercises for core stability. Instead, go for exercises which involve bracing the whole stomach and include the obliques, my own favourites being ?the plank' and the ?side raise bridge'.
Low Back Disorders, by Stuart McGill, published by Human Kinetics (2002)