There have been many discussions regarding the effects of spinal manipulation and the short and long term benefits of a chiropractic adjustment. The ultimate focus is a change in the biomechanics and therefore, the physiology surrounding the affected area of the spine. Although there is a significant amount of evidence showing the effects of spinal manipulation on the central nervous system, this study concentrated on the effects on the peripheral nervous system and paraspinal musculature, specifically of spinal manipulation on the paraspinal musculature in the lower thoracic and lumbar spines. The authors stated, “Many chiropractors palpate for tight muscle bundles in the paraspinal musculature as one indication of where to adjust. It seems reasonable to expect resting muscle activity, which can be monitored by EMG, to be abnormally high in the region of a tight muscle bundle” (DeVocht, Pickar, & Wilder, 2005, pp. 465-466). They went on to state, “In this descriptive study, we have further explored the phenomenon of reduced EMG activity after [spinal manipulation] to better understand the immediate effects of [spinal manipulation]” (DeVocht et al., 2005, p. 466).
The results of the study showed, “With EMG recordings obtained from 2 paraspinal muscle sites on each participant (except for one), 27 of the 31 pretreatment resting EMG levels decreased after treatment. During the 5 to 10 minutes of the treatment protocol, distinct changes (both increases and decreases) in the level of EMG activity were often observed” (DeVocht et al., 2005, p. 470). Ultimately the study revealed, “… the reduction of resting EMG activity after [spinal manipulation] that we observed in the greater majority of cases is consistent with and supportive of the commonly held perception that tight muscle bundles are associated with low back pain and that they can be alleviated by [spinal manipulation]” (DeVocht et al., 2005, p. 470).
Dr. Sean Billings DC, FIAMA, CCSP- Premier Alternative Health Center- 473-0399
DeVocht, J. W., Pickar, J. G., & Wilder, D. G. (2005). Spinal manipulation alters electromyographic activity of paraspinal muscles: A descriptive study. Journal of Manipulative and Physiologic Therapeutics, 28(7), 465-471.