Symmetry of the Neck Muscles' Activity in the Electromyography Signal during Basic Motion Patterns.

The activity of muscles during motion in one direction should be symmetrical when compared to the activity of the contralateral muscles during motion in the opposite direction, while symmetrical movements should result in symmetrical muscle activation. The literature lacks data on the symmetry of neck muscle activation. Therefore, this study aimed to analyse the activity of the upper trapezius (UT) and sternocleidomastoid (SCM) muscles at rest and during basic motions of the neck and to determine the symmetry of the muscle activation. Surface electromyography (sEMG) was collected from UT and SCM bilaterally during rest, maximum voluntary contraction (MVC) and six functional movements from 18 participants. The muscle activity was related to the MVC, and the Symmetry Index was calculated. The muscle activity at rest was 23.74% and 27.88% higher on the left side than on the right side for the UT and SCM, respectively. The highest asymmetries during motion were for the SCM for the right arc movement (116%) and for the UT in the lower arc movement (55%). The lowest asymmetry was recorded for extension-flexion movement for both muscles. It was concluded that this movement can be useful for assessing the symmetry of neck muscles' activation. Further studies are required to verify the above-presented results, determine muscle activation patterns and compare healthy people to patients with neck pain.

Analysis of Clinical Pattern of Musculoskeletal Disorders in the Cervical and Cervico-Thoracic Regions of the Spine.

Background: Cervical spine disorders (CSDs) are a common cause of neck pain. Proper diagnosis is of great importance in planning the management of a patient with neck pain. Hence, the aim of this study is to provide an overview of the clinical pattern of early-stage functional disorders affecting the cervical and cervico-thoracic regions of the spine, considering the age and sex of the subjects. Methods: Two hundred adult volunteers were included in the study. Manual examination of segments C0/C1-Th3/Th4 was performed according to the methodology of the Katenborn-Evjenth manual therapy concept and the spine curvatures were assessed (cervical lordosis and thoracic kyphosis). Results: The most common restricted movement was lateral flexion to the left, and the least disturbed movement were observed in the sagittal plane (flexion and extension). The most affected segment was C7/Th1 (71.5% participants had problems in this segment), and the least affected segment was Th3/Th4 (69.5% participants had no mobility disorders in this segment). The number of disturbed segments did not differ between men and women (p > 0.05), but increased with age (r = 0.14, p = 0.04). Conclusions: Cervical mobility in adult population is frequently restricted. The number of affected segments increased with age and was not sex-dependent.