Cervical extensor endurance test: a reliability study

The purpose of this study was to determine the inter-rater reliability in detecting the presence of weakness of the neck extensors and differentiate the presence of weakness of the superficial versus the deep neck extensors in a symptomatic population. The presence of weakness of the neck extensors has been described to cause pain and dysfunction in the cervical region.

30 patients with a diagnosis of neck pain were randomly assigned and examined by two musculoskeletal physical therapists at a time, in order to determine the presence of weakness of the superficial versus the deep neck extensors. With the patient lying prone and head and neck past the edge of the table and the cervico-thoracic junction stabilized, the ability of the individual to sustain a chin tuck position in neutral for 20 s was evaluated. A positive finding for weakness of the deep neck extensors is the 'chin length' increasing with neck extension, as observed on the inclinometer, indicating a dominance of the superficial extensors of the neck. Weakness of both deep and superficial neck extensors was identified by the presence of neck flexion indicating an inability to hold the head up. Inter-rater reliability was determined using the Cohen's un-weighted kappa statistic.

For the cervical extensor endurance test, the inter-rater reliability was 'very good' (k = 0.800, SE of kappa = 0.109, 95% CI).

The cervical extensor endurance test may be incorporated as a simple yet effective test to determine the presence of weakness of the neck extensors and differentiate the presence of weakness of the superficial versus the deep neck extensors in a symptomatic population. The accuracy of the CEET as a test is still debatable, as it has not been compared to a diagnostic gold standard. Based on the results of this study, we speculate the CEET may still offer an initial sense of direction for clinicians treating neck dysfunction.