Newsletter July 2004

Core Stability Basics

by Derek Mansfield, Physiotherapist

With the recent explosion in popularity of Pilates exercise programs, terms such as core stability have begun to pass into common language. The uninitiated may be aware that this has something to do with the abdominal muscles, but for Physiotherapists the growing awareness of core stability has revolutionized the way they look at back pain. So what actually is core stability?

Let me just say from the outset that doing heaps of sit-ups and crunches won’t give you core stability. These exercises target the wrong muscles and work them in the wrong fashion (more on this later). It’s convenient at this point to divide the notion of core stability into two distinct areas – the specific exercises used by physiotherapists in the rehabilitation of low back pain (which forms the subject of this article), and Pilates, which was originally designed as a holistic system of strengthening exercises incorporating specialized equipment or floor classes. Until fairly recently Pilates was the domain almost exclusively of dancers and gymnasts.

Core stability refers to the ability of certain, specialized muscles to prevent uncontrolled and potentially injurious movement of the low back, trunk or lumbar spine. It’s important to have adequate core stability, as powerful muscles attaching to the trunk initiate practically all sporting movements and most everyday ones. These movements are more efficient if these power-generating muscles have a stable base to work from. Forces transferred up the legs or arms (e.g. from running or hitting a tennis ball) are also absorbed and transferred in the trunk. If these aren’t controlled it can injure your back as well. Ever jarred your back when you missed a step? That’s force transfer at work.

It’s for this reason that a physio may look at core stability in an individual with seemingly unrelated problems – a hamstring strain, for example, where an inability to properly control spinal movement can contribute to reinjury or delayed recovery.

The problem is these muscles become inhibited (think of it as being similar to a software crash) when you have back pain, and significantly, they don’t necessarily automatically switch back on once the pain settles. They lose their memory and timing, such that if they do come back on, their protective abilities can be delayed. Moreover, research has shown that if the core stabilizers don’t work well, the back can be predisposed to further or recurrent injury. This has been studied and well-documented in physiotherapy literature.

An analogy: imagine that you are carrying five milk crates (your vertebrae), stacked on top of one another, with only a loose piece of string attaching them to each other (ligaments). Without some form of external bracing or buttressing (your core stability muscles), it would be difficult to maintain balance of the crates, and, say, run at the same time. The string linking them together would help, but only once they’d become unbalanced. Your five lumbar vertebrae on their own are inherently unstable. The role of the core stabilizer muscles is to provide the external support that maintains balance of the whole system.