Shaun O’Leary, Deborah Falla, †, Paul W. Hodges, Gwendolen Jull and Bill Vicenzino, ,
†Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Denmark.
Division of Physiotherapy, School of Health and Rehabilitation Sciences, University of Queensland, Brisbane, Australia.
Received 27 September 2006; revised 18 May 2007; accepted 23 May 2007. Available online 19 July 2007.

Abstract
This study compared the effect of 2 specific cervical flexor muscle exercise protocols on immediate pain relief in the cervical spine of people with chronic neck pain. In addition, the study evaluated whether these exercise protocols elicited any systemic effects by studying sympathetic nervous system (SNS) function and pain at a location distant from the cervical spine. Participants were randomly allocated into either a cranio-cervical flexion (CCF) coordination exercise group (n = 24) or a cervical flexion (CF) endurance exercise group (n = 24). Measures of pain and SNS function were recorded immediately before and after a single session of the exercise interventions. Pain measures included visual analogue scale (VAS) ratings of neck pain at rest and during active cervical motion and pressure pain threshold (PPT) and thermal pain threshold (TPT) recordings over the cervical spine and at a remote site on the leg. Measures of SNS function consisted of blood flow, skin conductance, skin temperature, heart rate, and blood pressure. Immediately after 1 session of exercise, there was a reasonably sized increase of 21% (P < .001, d = 0.88) and 7.3% (P = .03, d = 0.47) in PPT locally at the neck for the CCF exercise and the CF exercise, respectively. There were no changes in local neck TPT with either exercise. Pressure pain threshold and TPT at the leg and SNS did not change after exercise. Only the CCF exercise demonstrated a small improvement in VAS ratings during active movement (change on 10-cm VAS: CCF, 0.42 cm (P = .04). This study shows that specific CCF therapeutic exercise is likely to provide immediate change in mechanical hyperalgesia local to the neck with translation into perceived pain relief on movement in patients with chronic neck pain.

Perspective
This study showed an immediate local mechanical hypoalgesic response to specific exercise of the cervical spine. Understanding the pain-relieving effects of exercise will assist the clinician in prescribing the most appropriate exercise protocols for patients with chronic neck pain.

Key words: Neck pain; therapeutic exercise; hypoalgesia; pain modulation

Supported by the Physiotherapy Research Foundation (No. 009/02) and the National Health and Medical Research Council (NHMRC) (ID 252771) of Australia. Deborah Falla was supported by a Fellowship awarded by the NHMRC of Australia (ID 351678) and Paul Hodges was supported by an NHMRC Principal Research Fellowship (ID 401599).
Address reprint requests to Dr. Bill Vicenzino, Division of Physiotherapy, University of Queensland, St Lucia Queensland 4072, Australia.

The Journal of Pain
Volume 8, Issue 11, November 2007, Pages 832-839