In an article published in the journal Clinical Biomechanics, the author reports that spinal manipulation of the middle back increases shoulder muscle activity. This seems to help reduce pain and improve function in patients with shoulder pain. ~ Dr. Broussard
Evidence for increased neuromuscular drive following spinal manipulation in individuals with subacromial pain syndrome
Clinical Biomechanics
Volume 90, December 2021, 105485
Amy K. Hegarty
Highlights
• Shoulder muscle activity is a key deficit in those individuals with shoulder pain.
• Spinal manipulation increased shoulder muscle activity in patients with shoulder pain.
• Shoulder muscle activity was related to improved shoulder pain and function.
• Neuromuscular drive mechanism may optimize use of manipulation.
Abstract
Background
Thoracic spinal manipulation can improve pain and function in individuals with shoulder pain; however, the mechanisms underlying these benefits remain unclear. Here, we evaluated the effects of thoracic spinal manipulation on muscle activity, as alteration in muscle activity is a key impairment for those with shoulder pain. We also evaluated the relationship between changes in muscle activity and clinical outcomes, to characterize the meaningful context of a change in neuromuscular drive.
Methods
Participants with shoulder pain related to subacromial pain syndrome (n = 28) received thoracic manipulation of low amplitude high velocity thrusts to the lower, middle and upper thoracic spine. Electromyographic muscle activity (trapezius-upper, middle, lower; serratus anterior; deltoid; infraspinatus) and shoulder pain (11-point scale) was collected pre and post-manipulation during arm elevation, and normalized to a reference contraction. Clinical benefits were assessed using the Pennsylvania Shoulder Score (Penn) at baseline and 2–3 days post-intervention.
Findings
A significant increase in muscle activity was observed during arm ascent (p = 0.002). Using backward stepwise regression analysis, a specific increase in the serratus anterior muscle activity during arm elevation explained improved Penn scores following post-manipulation (p < 0.05).
Interpretation
Thoracic spinal manipulation immediately increases neuromuscular drive. In addition, increased serratus anterior muscle activity, a key muscle for scapular motion, is associated with short-term improvements in shoulder clinical outcomes.