Decrease Pain Sensitivity.
Past research has found that spinal manipulation results in a decreased sensitivity to pain, but researchers wanted to find out if this was the result of the adjustment itself or because of the expectation of treatment. To find an answer, researchers divided participants into four groups: no intervention, spinal manipulation, sham manipulation, and sham manipulation with an instruction that the treatment they will receive has been shown to significantly reduce low back pain in some people. Pain sensitivity was assessed both pre- and post-treatment by applying heat to the body until participants reported it reached their pain threshold. The spinal manipulation group showed the greatest decrease in pain sensitivity.
Journal of Pain, February 2014