Magnitude, validity and responsiveness of dynamometer measured neck retraction strength in patients referred with neck pain to out-patient physical therapy.

[Purpose] The magnitude, validity, and reliability of dynamometer measures of neck retraction strength have been reported but not for individuals referred with neck complaints to physical therapy. The purpose of this study, therefore, was to describe neck retraction strength and its responsiveness and validity as a correlate of neck pain and disability among patients referred for physical therapy. [Participant and Methods] Twenty-six consecutive patients referred with neck pain participated. Their neck retraction strength was measured with a handheld dynamometer using a standardized procedure. Neck pain and disability were quantified using a numeric pain rating scale and the Neck Disability Index, respectively. [Results] Measurements of neck retraction strength increased significantly over the episode of care from 76.5 N to 119.5 N (standardized response mean=1.57 N). The correlation of retraction strength with neck pain was significant (r=-0.550); however, the correlation between retraction strength and Neck Disability Index scores was not significant (r=0.155). [Conclusion] Neck retraction strength measured with a hand-held dynamometer was informative and responsive for patients treated with neck pain. Retraction strength was correlated significantly with neck pain but not neck disability. This apparent inconsistency warrants further investigation.