dr  Jordan Duncan

dr Jordan Duncan

Of all the potential culprits for back pain, few get as much attention as core weakness. The belief that weak core muscles lead to back pain persists at all levels of healthcare, from physical therapists to chiropractors to orthopedic surgeons.

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

However, unquestioned points of view rarely lead to answers. Scientific advancement in any field is the result of people asking very serious, and often very fundamental, questions about the established consensus. In relation to the subject at hand, a natural question should be something like this: “If core weakness is a common cause of back pain, shouldn’t we expect back pain to be common when the muscles that stabilize the core are somehow weakened?”

One way to answer this question would be to look at pregnancy, a very common real-life example of severe trunk weakness. During pregnancy, the muscles of the abdominal wall undergo dramatic and sustained stretching, resulting in what is known as “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 of trunk weakness and back pain were correct, one would expect that back pain would be extremely common in postpartum women during this period.

A unique discovery from a research article provided us with tremendous insight into how to answer this question. In a study titled “Effectiveness of a Tailored Intervention for Pregnancy-Related Lumbar Girdle and/or Lumbar Pain Postpartum,” 869 pregnant women were recruited to determine the effect of two different interventions for pregnancy-related lumbar and/or posterior pelvic girdle pain immediately after childbirth.

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

Two weeks is well ahead of the expected time frame (4-6 weeks) for these elongated abdominal muscles to shorten and regain their normal core stabilization function. If trunk weakness were a common cause of back pain, 75% of these postpartum women would likely not have recovered spontaneously while their trunks were still very weak. Instead, one would expect that almost all of them should still be in pain due to their extreme pregnancy-related core weakness.

Today, pregnancy is a very unique circumstance that less than half of the population, on average, experiences only a few times in their lives.

So what about everyone else with back pain?

One of the most important factors in the etiology of back pain is sitting posture. While poor sitting posture can cause lower back pain on its own without additional life pressures, it often perpetuates the problem in those who already have the condition. Several studies have shown that over 80% of back pain cases are made worse by sitting.

Research has also shown that there is very little core muscle activity during slouching. Therefore, it doesn’t matter how strong your core is if you slouch, as these muscles offer virtually no protection. In fact, I would argue that the effect slouching has on the spine is more important than core strength in causing back pain.

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

All of this doesn’t mean there’s no value in strengthening your core. It’s important to strengthen every muscle in the body, and the core is no exception. But is it a common reason for back pain? This connection is unproven. Certainly, some cases of back pain respond to core strengthening, and core strength may even have preventive benefits. However, if you’ve spent months or years trying to strengthen your core muscles to relieve your low back pain, weakness is unlikely to be the cause.

dr Born and raised in Kitsap County, Jordan Duncan graduated from the University of Western States in 2011 with a PhD in Chiropractic. He practices at Silverdale Sports and Spine. He is one of the few Washington state chiropractors certified in the McKenzie Method.

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