Research: Chiropractics impact on Strength, Fatigue and Muscle.



“What we can say based on this study is that when we adjust subluxations, we improve strength, we prevent fatigue and we change the way the brain drives our muscles. That’s pretty cool” said Heidi Haavik, one of the brains behind a recent study examining changes in H-reflexes and V-waves following spinal adjustmentsi.

Haavik isn’t referring to ‘subluxations’ in terms of the now out-dated bone out of place, squashing a nerve view. Instead, she is viewing them through the lens of proven research that paints subluxations as central-segmental motor control problems. That is, dysfunctions that occur when the central nervous system isn’t controlling the movement pattern of a segment of the spine as well as it should be.
“When we adjust dysfunctional segments or subluxations, we change the way the brain processes what’s going on in our bodies. Hence we are able to better process all that sensory information from through-out the body, and control the body in a better way,” says Haavik.

This view was firmly backed up by findings of the recent study, which was enabled through a partnership between Spinal Research, the New Zealand College of Chiropractic and the Hamblin Trust.
In the fully randomised research process, a control group of participants were set up but not adjusted. This group was asked to perform maximum contractions using leg muscles and was seen to fatigue over the course of the study.
The researchers contrasted this with the group that did receive chiropractic adjustments and saw a major shift in the way the brain drove the muscle. “There was a change in the H-reflex happening at the spinal cord level. Our results were showing that change (in the H-reflex) isn’t a spinal cord phenomenon. The brain was changing that reflex effect. Our subjects got stronger (in comparison to the control group)” observed Haavik and her fellow researchers.

The study showed:
– an increase of almost 60% in the electrical activity readings from specifically targeted muscles
– a 16% increase in absolute force measures
– a 45% increase in the drive from their brain to their muscle
– a small but significant shift in the H reflex curve, which is a neurophysiological measure of spinal cord excitability

Another interesting finding occurred when Haavik was writing up the results of this research. She came across another study that was almost identical in its methodology, but was comparing three weeks of strength training to three weeks of endurance training. “Our results were almost identical to three weeks of strength training” she said.
These are compelling research outcomes which back-up what chiropractors and their patients already know: that people function better with chiropractic care. It presents us with great opportunity in terms of communicating chiropractic value and impact to the greater health community.

However according to Haavik, this is just the beginning of what can be discovered and proven through research. “We know that adjustments cause improvements, but how long does this last for? What about after an hour? What about after a week? What happens after three weeks of chiropractic care? What happens after a month? If there was more funding available, we could get so much more done.”


Reproduced from the Australian Spinal Reasearch Foundations Research release.

i 1 Niazi IK, Türker KS, Flavel S, Kinget M, Duehr J & Haavik H. (2015) Changes in H-reflex and V waves following spinal manipulation. Experimental Brain Research. In press. DOI: 10.1007/s00221014-4193-5
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