Cervical extensor muscle activity during neck tasks in individuals with and without neck pain: A systematic review.

Background: In the context of neck pain, neck muscle activity adapts through diverse regional coordination modifications during tasks. Although patterns of cervical flexor muscle impairment are well-documented, patterns in the cervical extensor muscles are less clear, hindering assessment and treatment. Despite studies revealing adaptations in the cervical extensor muscles, outcome measure heterogeneity complicates interpretation, particularly between superficial and deep muscles. To address this, we conducted a systematic review comparing neck extensor muscle activity between symptomatic and asymptomatic groups during tasks, aiming to inform clinical practice.

Objectives: To compare the cervical extensor muscle activity during neck tasks between symptomatic and asymptomatic groups, using complementary examination tools.

Methods: Up to January 2024, experimental studies assessing cervical extensor muscle activity during neck tasks in adults with idiopathic or traumatic neck pain, or cervicogenic headache compared to healthy controls were included. Study selection involved 2 blinded reviewers. Electronic databases (Medline, Scopus, and Embase), reference lists, and relevant reviews were screened. Data extraction focused on the results of the between-group motor activity comparisons. Critical appraisal used the JBI appraisal checklist for analytical cross-sectional studies.

Results: Twenty-three studies met the inclusion criteria, involving 932 participants and reporting 170 comparative assessments of 8 muscle groups, encompassing 4 main motor activity outcomes: recruitment, timing, fatigue, and directional activation. Significant differences were noted for motor recruitment in 51 % of comparisons, for timing in 35 %, and fatigue in 33 %, with consistent differences in directional activation. Impaired activity in individuals with neck pain compared to those without was found in 47 % of comparisons for superficial muscles and 65 % for deep muscles.

Conclusions: Motor activity adaptations during neck tasks appear to be unpredictable in individuals with neck pain, with a tendency for change in the deep cervical extensor muscles. Further high-quality studies are needed to confirm these findings, considering various contraction parameters, multiple muscle analyses, and several motor activity outcomes.

Trial registration: PROSPERO International Prospective Register of Systematic Review CRD42022285864.