Tag Archives: Chiropractic Research

What Does Chiropractic Adjustment Do?

This is a common question to chiropractors.  Chiropractic manipulation is not just joint popping. In fact the audible pop doesn’t even need to occur for a successful adjustment, though it often does, and some patients and doctors like to hear it. Research has found that “pop” or not, the same benefits are experienced.

The mechanism of why manipulation works is not fully understood. One thing that is understood is that it does work. Most of the simple explanations are incomplete or just plain wrong. The most recent research points to a more complex reason for the therapeutic effects of chiropractic manipulation. Many things are occurring at the same time that provide the benefits. There are some known things that can begin to explain why manipulation works. Here they are presented in no particular order.

1. Manipulation can reduce pressure on the nerves. Your nervous system is the control center of your body, and it is not without weaknesses.  Nerves and nerve bundles are soft tissue.  They don’t function well under physical pressure.  In fact it has been shown that inflammation, a bulging disc, or fragment floating around can interfere with proper nerve conduction.  The stuck joint as discussed previously can also physically be stuck pressing on a nerve, or could be causing inflammation that is pressing on the nerve, or could just be moving in a way that rubs the nerve.  In any case.  The adjustment can cause a relief of this pressure. through movement of the joint to the correct position, or motion.

2. Proprioceptive stimulation triggers the release of endorphins. These endorphins cause a near instant and temporary relief similar to pain medication making you less aware of the problem. This “trick” of the body can cause a secondary benefit, that of relaxing local tissues such as trigger points or tight musculature that may be “pinching” nerves.

Image by: Luis Solis

3. Manipulation provides improved nutrient supply. The cartilage and other structures inside of a joint have no blood supply. These structures get their nutrients through motion. The blood supply goes to the outside of the joint and nutrients move into the synovial fluid of the joint. Joint motion moves this fluid around thus providing fresh nutrients to all parts of the joint. If a joint becomes “locked down” by muscle spasm, scar tissue, a cast, or any other means for a prolonged period of time the joint begins to feel stiff. You know the feeling of needing to stretch after sitting in the car for a long time.

The facet joints in your spine are particularly vulnerable to this problem because they work in tandem and because of the body’s amazing ability to compensate. Your facet joints all work together, if one is injured it can become locked down to prevent further injury. When this happens you may get the desire to stretch or move your back. This usually works, but if all of the other joints compensate for the problem joint and take that added stress of movement on themselves then the problem joint stays locked down. Specific manipulation induces full range of motion and synovial fluid movement.

4. Neuromuscular retraining.  The brain also records these proprioceptive signals from the joints motion. Especially for chronic conditions the brain is in need of retraining regarding the motion of that joint. Manipulation takes a joint through its full range of motion. This new input is then stored and replayed in the brain, similar to muscle retraining that physical therapists will do, or physical training of athletes, when the body has done the motion enough times it “remembers” it.This retraining provides a functional correction that may provide pain relief.

Many other benefits have been observed, and still others suspected.Research is still going on and much more is needed.

Scientific Studies Interpreted


Journal of Manipulative and Physiological Therapeutics

Since the dawn of modern science answers to life’s questions have been sought through studies.  I highly recommend research and physicians using research to the advantage of their patients.  I encourage patients to stay informed through reading research.  In life, online, and even the media you hear things like, “oh it’s true, they’ve done studies.”  I’m not sure who “they” are and whatever study is being referred to probably didn’t mean what you thought it did.


American Chiropractic Association

Chiropractic, for good or bad, has been forced into research by the well-meaning movement of evidence based medicine.  This movement, as with most things, falls short when strictly applied to every scenario.  There are always too many exceptions.  One of the most well-known, and a great read, is a farcical review article discussing, “parachute use to prevent death and major trauma related to gravitational challenge.”  This article was actually published in the British Medical Journal in 2003.  It inferred that because there was no research studies to show the efficacy of parachute use that their use should be discontinued as a preventative health care measure.


Index to Chiropractic Literature

The truth is that most studies are either to vague or to specific or too something to be applied directly in real life situations.  They all have flaws and weaknesses.  Even the gold standard Double Blind Randomized Controlled Trial is not perfect.  Most of the good studies admit and disclose their bias so that readers can take that into consideration when determining usefulness.  If you don’t understand research bias don’t worry there are entire college courses dedicated to the topic, if you want to learn more you can begin here  Google results: research bias.

To make things simple for you, there is no perfect study because people are not perfect.   This principle becomes utterly clear in online debates that usually end in name calling and any truth lost to both parties.


The Chiropractic Resource Organization

I often cite research on my blog, and sometimes people agree and sometimes they disagree with the research.  You are welcome to do so.  I highly recommend reading research for truth.  The best RCT can be useless and the anectdotal single case study may hold the answer to the problem you face.  Don’t discount evidence of any kind.  Read it for truth and accept the research for what it is, one possible view of a whole situation.