The effect of acute cervical traction on neck muscle stiffness: A case-control examination in individuals with idiopathic chronic neck pain

Abstract

Background: Cervical traction is a common intervention in physical therapy practices to manage cervical pain and reduce neck muscle stiffness (e.g., resistance to passive stretching). However, more definitive research is needed to understand how this intervention influences muscle stiffness in individuals with idiopathic chronic neck pain.

Objectives: To determine the effect of a single session of supine cervical traction on stiffness of the upper trapezius (UT) and middle scalene (MS) in participants with idiopathic chronic neck pain using ultrasound shear wave elastography.

Methods: We recruited 18 participants (14 F, 4 M) exhibiting mild-to-moderate idiopathic chronic neck pain and 17 healthy controls (12 F, 5 M) for this study. Cervical traction was applied using a 9 kg force for 6 sets of 5 min with breaks in between. Ultrasound shear wave elastography images were acquired bilaterally from two UT sites and one MS site before and after the cervical traction session to measure muscle stiffness and at 2.5 min and 5 min into each set for one randomized location.

Results: Cervical traction significantly reduced stiffness in both UT sites during a 5-min application of traction (both p < 0.001) but did not significantly affect MS stiffness (p = 0.07). However, the effects were temporary as stiffness for all six muscle sites returned to their baseline levels after the 30 min session was completed.

Conclusion: A single session of cervical neck traction reduces the stiffness of the upper trapezius muscles while traction forces are applied, but these changes do not persist after removing traction.

Keywords: Cervical spine; Muscle mechanics; Physical rehabilitation; Ultrasound shear wave elastography.