Questioning the link between low-back pain and core weakness

Of all the potential culprits for low back pain, few get as much attention as core weakness. The belief that a weak core will lead to low back pain is perpetuated throughout all levels of healthcare, from physical therapists to chiropractors to orthopedic surgeons.

People are routinely told that they need to strengthen their core muscles to help their ailing backs, and this advice is so common that it is rarely questioned. In addition to medical professionals, the notion that your low back pain is due to a weak core is touted by television commercials, the internet, trainers at your local gym, and even your family and friends.

Unquestioned viewpoints, however, rarely lead to answers. Scientific progress in any field is the result of people asking very serious and oftentimes very basic questions about the established consensus. As it pertains to the topic at hand, a natural question should go something like this, “If core weakness is a common cause of low back pain, shouldn’t we expect low back pain to frequently occur if the muscles that stabilize the core are weakened in any way?”

One way to help answer this question would be to take a look at pregnancy, a very normal, real-life example of severe core weakness. During pregnancy, the muscles of the abdominal wall undergo dramatic and prolonged elongation, creating what is known "stretch weakness." Physiologically, it takes about 4-6 weeks after delivery for these core muscles to shorten and return to their normal level of function. If the common notion regarding core weakness and low back pain were correct, one would expect low back pain to occur at an extremely high rate in postpartum women during this time frame.

A unique discovery from a research article offered us tremendous insight into answering this question. In a study titled "Effectiveness of a tailor-made intervention for pregnancy-related pelvic girdle and/or low back pain after delivery," 869 pregnant women were recruited to determine the effects of two different interventions for pregnancy-related low back and/or posterior pelvic girdle pain immediately after delivery.

The most interesting finding from this article wasn’t which treatment was more effective. Rather, it was that 650 women were excluded from the study because their low back and/or posterior pelvic girdle pain spontaneously resolved within two weeks of delivery.

Two weeks is well before the expected timeframe (4-6 weeks) for these elongated abdominal muscles to shorten and regain their normal core stabilizing function. If core weakness was a common cause of low back pain, spontaneous recovery likely wouldn’t have occurred in 75% of these postpartum women while their core was still very weak. Instead, it would be expected that nearly every one of them should still be experiencing pain as a result of their extreme pregnancy-induced core weakness.

Now pregnancy is a very unique circumstance, experienced by less than half the population on average only a handful of times in their life.

So what about everyone else with low back pain?

One of the most important factors in the etiology of low back pain is sitting posture. While poor sitting posture may produce low back pain on its own without any additional strains of living, it often perpetuates the problem in those already suffering from the condition. Several studies have shown that over 80% of back pain cases are aggravated by sitting.

Research has also demonstrated that there is very little muscular activity of the core during slouched sitting. Therefore, when you sit slouched it doesn’t matter how strong your core is because these muscles provide virtually no protection. In fact, I would argue the effect that slouched sitting has on the spine is more important than the strength of the core muscles in the development of low back pain.

We know that people with very strong cores, even professional athletes, can get low back pain like everyone else. Tiger Woods, who is no stranger to the gym or core stability, has undergone five back surgeries in his life. He is a great example demonstrating that having a strong core doesn’t necessarily prevent or fix lower back pain.

Now all of this doesn’t mean that there isn’t value in strengthening your core. It is important to strengthen every muscle in the body, and the core is no exception. But is it a common reason for low back pain? That connection hasn’t been proven. Certainly, some cases of low back pain respond to core strengthening, and there may even be some preventative benefit to having a strong core. However, if you have been strengthening your core muscles for months or years on end trying to resolve your low back pain, it’s unlikely that weakness is the cause.

Dr. Jordan Duncan was born and raised in Kitsap County and graduated from the University of Western States in 2011 with a Doctor of Chiropractic Degree. He practices at Silverdale Sport and Spine. He is one of a small handful of chiropractors in Washington state to be credentialed in the McKenzie Method.

This article originally appeared on Kitsap Sun: Questioning the link between low-back pain and core weakness