Motion Stability's Blog

Are crunches the best exercise to eliminate my back pain? by charlestlee

Brian Yee PT, MPhty, OCS, FAAOMPT 

No. There is a misunderstanding that the stronger your abs are, the better it is for your back. Although strong abs can help stabilize your spine, current research indicates that there are different roles of muscles in the trunk. Generally speaking, the smaller muscles of your spine called ‘local’ muscles help stabilize the spine in low load situations such as prolonged standing, sitting, and light movements such as bending to brush your teeth. While, there are ‘global’ muscles that are the larger muscles –  such as the rectus abdominis, obliques, and back paraspinal muscles that are designed more for movement, power, and stabilization at higher impact.
It is important to have both ‘local’ and ‘global’ systems working correctly. The ‘local’ muscles – transversus abdominis, pelvic floor, and diaphragm help provide intra-abdominal pressure to your trunk. This pressure is similar to a sealed can of soda that maintains the carbonation of a drink. If you were to open the can, you would lose its pressure. Similarly, research from the University of Queensland suggests that with back pain the smaller muscles lose control and thus your intra-abdominal pressure is not as effective to stabilize your spine. Also, along the back of your spine is a muscle called the multifidus. The deeper portions of it run vertebra to vertebra and they are also designed to provide stability to the spine.
We can utilize real-time ultrasound imaging to visualize and cue a client to contract the ‘local’ muscles correctly. Once the ‘local’ muscle work correctly, it is important to do exercises that integrate the ‘global’ muscles – not just with the abs, but also the muscles around the trunk. It is much more effective to do exercises that coordinate the use of these muscles rather than just doing abdominal crunches. Please consult with a qualified health practitioner to guide you through the proper exercise progression