Lower Trapezius Muscle Strength in Individuals With Unilateral Neck Pain

Abstract

Descriptive and within-subject comparative study. To examine lower trapezius muscle strength in individuals with unilateral neck pain. Previous research has established the presence of reduced cervical flexor, extensor, and rotator muscle strength in individuals with neck pain. Some authors have suggested that individuals with neck pain have limited strength of the lower trapezius muscle, yet no research has investigated this claim. Twenty-five individuals with unilateral neck pain participated in this study. Participants completed the Northwick Park Neck Pain Questionnaire (NPQ) as a measure of disability. Side of neck pain, duration of neck pain, and hand dominance were recorded. Lower trapezius muscle strength was assessed bilaterally in each participant, using a handheld dynamometer. A significant difference in lower trapezius strength was found between sides (P<.001), with participants demonstrating an average of 3.9 N less force on the side of neck pain. The tested levels of association between NPQ score and percent strength deficit (r = -0.31, P = .13), and between symptom duration and percent strength deficit (r = -0.25, P = .22), were not statistically significant. No significant association was found between hand dominance and side of stronger lower trapezius (P = .59). The results of this study demonstrate that individuals with unilateral neck pain exhibit significantly less lower trapezius strength on the side of neck pain compared to the contralateral side. This study suggests a possible association between lower trapezius muscle weakness and neck pain.