The safety, efficiency and effectiveness of any CrossFit exercise depends on the ability of your stabilizing muscles to do their job with maximum efficiency. Your deep core muscles are your most important dynamic stabilizers. Much of the research regarding core stabilization began here in Australia, but how one should engage these core muscles is a subject that sparks controversy.
The Paul Hodges Studies
In 1999, University of Queensland physiotherapist Paul Hodges and his team published a study put the concept of core stability on the map. Based on the results of his research, people free of back problems instinctively activate their deeper core muscles – particularly the transversus abdominus — a fraction of a second before they perform the movement. In contrast, back pain sufferers have a delayed transversus abdominus reaction.
The Abdominal Hollowing Method
Hodges and his team developed an abdominal hollowing method, designed to consciously activate the transversus abdominus muscle, along with the multifidus – another core muscle – during movement. When you exhale, your transversus abdominus presses against the diaphragm to help you expel the air. The abdominal hollowing movement takes advantage of the muscle’s natural function. Take a breath in. As you fully exhale, suck in your lower abdominal muscles toward the spine to the point of tightness. The abdominal hollowing technique engages the deeper core muscles, but not the superficial abdominal muscles, such as the rectus abdominus, the internal obliques and the external obliques.
In the past few years, some studies have challenged the effectiveness of the abdominal hollowing method. Canadian biomechanics expert Stuart McGill contends that the focus on just two core muscles is an overly simplistic approach to core stabilization,particularly when dynamic stability is evaluated within a three-dimensional context as opposed to stability in static, single plane positions. McGill argues that during athletic events, unpredictable forces come from all directions. The results of one study indicated that if a posterior perturbation – or unsuspected push from behind – occurs on the spine, abdominal hollowing does not protect the spine from flexing in response to the blow. Abdominal bracing, however, reduced spinal flexion by 43 percent – possibly enough to prevent a serious back injury.
Abdominal bracing involves a co-contraction of the abdominal and gluteal muscles. It’s the type of abdominal contraction you would use if someone was about to punch you in the belly. Unlike the abdominal hollowing method, abdominal bracing does not isolate the transverse abdominus and the multifidus. Instead, it engages the rectus abdominus, the obliques and gluteal muscles.
So Which is Better?
It depends on what you are doing. The abdominal hollowing technique might suffice for a Pilates class, or for a physiotherapy session, especially for a lower back injury. Hollowing is also useful for support during daily tasks, such as lifting objects that are not all that heavy. Bracing, in that type of situation, would be overkill.
The demands of CrossFit, however, are far more dynamic, especially if you are practicing some of the CrossFit combative moves. Abdominal bracing would then be the preferred method. Ask your physiotherapist or personal trainer to teach you the abdominal bracing and hollowing techniques.
Please call Happy Physio on (08) 9272 7359.