This is a common question to chiropractors. Most chiropractors don’t explain it very well for many different reasons. I usually don’t have time. If you’re reading this however you are already interested, and I have time at the moment. So, here goes…
Chiropractic manipulation is not just joint popping. In fact the audible pop doesn’t even need to occur for a successful manipulation, 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 completely 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. It is suggested that many things are occurring at the same time that provide the benefits. There are three known things that can begin to explain why manipulation works. Here they are presented in no particular order.
1. 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.
2. 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.
3. 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.