Low Back Pain (LBP) is a common and recurrent problem. It has been estimated that approximately 80 percent of people in western countries will experience low back pain at some point in their lives.
Most of these cases will resolve within two to four weeks, however, within one year following the first episode of LBP, 60-80 percent of people will have recurring pain. One of the treatments often recommended for LBP is “core training.” The term “core training” has become confusing, as everyone from physical therapists to trainers on TV are using it—often with very different ideas of what it means.
There are important distinctions between the stabilization exercises used for therapeutic reasons and those that are used for sports and conditioning.
All “core training” programs involve the trunk muscles, but newer research has shown that the various muscles of the trunk serve very different purposes. Some act as position sensors, some act as stabilizers, and others generate forceful movements.
Functionally, the trunk muscles can be divided into two major groups—the larger outer muscles (“global” muscles) and the smaller inner muscles (“local” muscles). Most non-therapeutic “core training” programs focus on the large outer trunk muscles that you can visibly see. These muscles span multiple vertebrae and largely run between the rib cage and pelvis.
While strength in these “global” trunk muscles is very important for overall function and athletic performance, they are primarily movers of the spine and are not attached in such a way that they can effectively control alignment or motion between vertebrae. Thus, while this type of “core training” by itself may give you “six-pack abs” and improve athletic performance, it likely is missing the mark if you have low back pain.
Research on low back pain has demonstrated that the structure and function of the inner core muscles is altered even after the first episode. The messages from the nervous system that tell these muscles when to fire become disrupted, and these muscles are essentially “knocked offline.”
Furthermore, studies have shown that recovery of these deep trunk muscles does not spontaneously occur, even if the pain resolves and normal activities are resumed (this is true even in highly-trained athletes whose outer core muscles are strong). The recovery and normal firing pattern of these deep muscles is only restored if they are specifically retrained. When people are instructed in how to properly contract these inner core muscles during activity, there is a significant decrease in both intensity and recurrence of low back pain episodes.
What are these deep inner core muscles? Most research emphasizes the role of the transversus abdominus and lumbar multifidus muscles. The pelvic floor muscles have also been implicated as being important in segmental stabilization of the spine and pelvis.
All joints of the body, as with any other joint (such as a door hinge), must remain properly aligned for the joint to track correctly and avoid abnormal wear and tear. In the spine, joint stability refers to the ability of the joint to move through its full range in a controlled manner, without excessive or abnormal motion.
The joint structures (ligaments, discs, and facet joints) by themselves are not able to ensure normal tracking, as the spine relies heavily on motor control provided by the nervous system and correct muscle firing patterns to maintain proper alignment and support. Because these inner core muscles are close to the spine and attach to adjacent or nearby vertebrae, they are structurally able to stabilize one vertebra on another, guiding their motion and protecting the joints against damaging or painful movements.
If you have low back pain of any kind you should seek out your local physical therapist. Physical therapists are specially trained in assessing the function of these deep core muscles and your spinal mobility, stability, and posture. After assessing your individual biomechanics, your therapist will put together an individualized program of exercises that are specific to your problem, properly instruct you to fire your muscles correctly, and progress your activity in a pain-free and safe manner.
A typical progression of therapeutic “core training” would involve a therapist teaching you how to find and activate these deep muscles in a controlled way, involving minimal spinal motion. As you become more skilled at activating these deep muscles, your therapist would then progressively challenge them to stabilize your spine in different planes of motion with increasingly more dynamic exercises related to your functional activities.
While most people with LBP will benefit from consultation with a physical therapist, people with pain due to spine problems that disrupt the structural integrity or motor control of the spine (such as degenerative disc disease, arthritis, underlying hypermobility, or back pain following pregnancy) may especially benefit from a therapeutic “core training” program that emphasizes activation of these deep inner core muscles.