Evaluation activities of superficial neck muscles during fast upper limb movements in patients with chronic non-specific neck pain and a control group

Neck pain is one of the most common musculoskeletal disorders in industrial society. There are complex changes in motor control of cervical spine in neck pain patients. The aim of this study was to compare the latency of activation of neck muscles during upper limb movement between neck pain patients and healthy subjects. Eighteen chronic non-specific neck pain patients and eighteen healthy subjects who were matched in age، weight and height participated in this study. Subjects were standing on the ground and performed flexion and abduction movement of the right arm until at least 90 degree in five trials and consequently surface electromyography of neck muscles was recorded. Activation time of neck muscles was determined in comparison with the activation time of deltoid muscle (as an event) and then compared between two groups. Findings of this study showed that in patients with chronic neck pain and healthy subjects during upper limb flexion and abduction movements، the superficial neck muscles were activated after deltoid activation. As well as in the neck pain patients compared to the healthy subjects superficial neck muscles onset was significantly appeared with delayed (P<0. 05). In patients with neck pain compared to healthy controls، the neck muscles were significantly delayed in responses to the internal perturbations of fast upper limb movements. It may be to increase the risk of injuries of neck region during fast upper limb movements.