Goss DA Jr,et al.
J Electromyogr Kinesiol. 2012 Oct;22(5):663-9. doi: 10.1016/j.jelekin.2012.01.004. Epub 2012 Jan 28.

Affiliation
Ohio Musculoskeletal and Neurological Institute, Ohio University, Athens, OH 45701, USA.

Abstract
The purpose of this study was to determine if non-thrust manual therapy (MT) attenuated side-to-side differences (asymmetry) of the erector spinae (ES) stretch reflex amplitude in nine patients with chronic LBP. We used electromechanical tapping to elicit short-latency stretch reflexes (SR) from the ES muscles before and after non-thrust MT. A large asymmetry in the SR was observed at baseline, with the higher of the paraspinal sides exhibiting a 100.2±28.2% greater value than the lower side. Following the intervention, this SR asymmetry was reduced (100.2±28.2% to 36.6±23.1%; p=0.03). This change was largely due to reduced amplitude on the side that was higher at baseline (35% reduction following treatment; p=0.05), whereas no change over time was observed in the low side (p=0.23). Additionally, there was no difference between the respective sides following the intervention (p=0.38), indicating that the asymmetry was normalized following treatment. These findings provide insight into the mechanism(s) of action of non-thrust MT, and suggest that it acts to down regulate the gain of the muscle spindles and/or the various sites of the Ia reflex pathway. Ultimately, developing a better understanding of the physiologic effects of manual therapies will assist in optimizing treatment strategies for patients with LBP.

Copyright © 2012 Elsevier Ltd. All rights reserved.

PubMed Reference:  http://www.ncbi.nlm.nih.gov/m/pubmed/22285058/