Differences in neck surface electromyography, kinematics and pain occurrence during physiological neck movements...

Neck pain has been associated with altered muscle activity and impaired kinematics. Patients frequently report pain during physiological neck movements. Previously, the average muscle activity during these movements has been measured. However, muscle activity is modulated by the position in the range of movement, hence the study of neck muscle activity in discrete sections of the range of movement is warranted. Evidence is conflicting regarding range of movement restriction in neck pain. No study has assessed the point in the range of movement at which pain occurs. This study aimed to investigate neck kinematics, muscle activity and pain during physiological neck movements in participants with and without neck pain.

Neck kinematics and surface electromyography were recorded continuously and analysed in 10° increments during forward and side flexion, extension and rotation of the neck in 20 neck pain and 20 asymptomatic participants. Point of pain occurrence in the range of movement was recorded.

Neck pain participants demonstrated significantly lower activity of scalene during flexion and extension, and a non-significant higher activity in sternocleidomastoids during rotation. No differences in neck kinematics were observed. 65% of neck pain participants reported pain during at least one neck movement. Pain was reported in the last ≈20-40% of the range of movement.

Exercises used in current practice to minimise scalene activity may not be appropriate for all neck pain patients. Restricted range of movement is not a consistent feature of neck pain. Movement associated neck pain is present at the end of range of movement, which has implications for the study of neck pain and rehabilitation.