Introduction: Fatigue of the neck muscles can lead to change in upper limb proprioception, motor patterns and kinematics. Restricted range of motion is a characteristic of myofascial trigger point. There is no evidence indicating an association of fatigue with restricted range of motion and non specific myofascial pain syndrome without underlying disease. This study evaluates cervical motions in flexion/extension, side bending and rotation before and after fatigue. Clinically, proprioception is evaluated using the Joint Position Sense Error (JPSE), which reflects a person’s ability to accurately return his head to a predefined target after a cervical movement. This study design is randomized control trial.
Methods: 23 healthy right handed volunteers (11 males and 12 females) from a physical therapy clinic in rehabilitation faculty participated in the study.
Fatigue protocol was done, the recordings of pain threshold and intensity and kinematics, before and after fatigue, were all repeated.
Results: Neck muscle fatigue had different effects on neck kinematics for each group. JPSE in neck side bending repositioning was significantly greater following the upper trapezius muscle fatiguing protocol in a frontal plane.
Conclusion: The increased accuracy was most pronounced for movements directed towards the activated side. Hence, prolonged unilateral neck muscle contraction may increase the sensitivity of cervical proprioceptors. Cervical range of motion
in side bending was the only variable associated with changes in neck pain.
Level of evidence: IIIb