The term “core” has been historically poorly defined as abdominals or the “six-pack” muscles. More accurately, the core is made up of a system of deep muscles in our trunk that contribute to functional stability of our spine. The core muscles are more than movers like many of the muscles we train or strengthen. The primary function of the core muscles is to support the spine from the load of everyday stresses such as bending, lifting, twisting or simply sitting. These core muscles include the transversus abdominus, a corset-like muscle surrounding our trunk, the multifidi which stabilize one segment of the vertebrae to the next, the internal obliques, and the pelvic floor muscles. These muscles work together to counterbalance external loads and forces produced by our mover muscles. When the core functions optimally, these muscles protect the spinal vertebrae, discs and ligaments from injury. Having a weak or inhibited core puts an individual at increased risk of back pain and injury.
Ideally, when we initiate a movement our core muscles activate before our global mover muscles, superficial muscles that produce torque to move a joint. Studies show individuals with chronic low back pain are more likely to have decreased thickness of the transversus abdominus, the primary core stabilizer muscle, as well as delayed timing of contraction of the lumbar multifidi and transversus abdominus. This means that in people with low back pain, primary core stabilizer muscles turn on more slowly than those in healthy individuals. However, there is literature that supports the success of core strength and stabilization exercises as part of low back pain treatment. Skilled professionals help clients find and activate the correct muscles and design client specific exercise programs to train and strengthen these muscles.
The initial phase of core training involves neuromuscular control: teaching the individual how and when to turn on the core muscles on. These stability exercises can be progressed to more functional situations that are applicable to every day life, such as reaching, bending and twisting, as well as sport specific movements. With training, the core muscles can become programmed to turn on at the correct times and do their job to adequately stabilize the spine. The goal of a proper core stability and strengthening program in individuals with low back pain is to decrease pain and risk of recurrence as well as to increase participation in physical function.