• J R Cram and W J Kneebone.
• Sierra Health Institute, Nevada City, Calif 95959, USA.
• J Manipulative Physiol Ther. 1999 Nov 1; 22 (9): 570-5.

BackgroundIn the comprehensive assessment of painful conditions, dynamic surface electromyography (sEMG) and range of motion (ROM) recordings can provide information regarding muscle spasm, antalgic postures, fear of pain (protective guarding), muscle injury, and disordered movement caused by pain. This study examines ROM and sEMG patterns observed during cervical flexion.ObjectiveTo demonstrate 2 distinctive sEMG recruitment and dynamic ROM patterns observed during cervical flexion and return to mid-line.DesignSingle-subject design with independent measurement of dynamic ROM and sEMG.SettingApplied clinical setting.ParticipantsTwo subjects with normal ROM and cervical muscles were studied.Main Outcome MeasureOne subject was studied with sEMG. looking at the cervical paraspinals and sternocleidomastoid muscles; the other subject was studied with an active ROM device. Three cervical movements were studied: lower cervical flexion, atlantoaxial (upper) cervical flexion, and a combination upper/lower cervical flexion.ResultsThe active ROM device indicates larger movements (higher degrees of flexion) for the lower cervical flexion compared with upper flexion. The combined movement indicates a differential movement from 2 spinal segments. The sEMG recordings indicated differential recruitment patterns. The sternocleidomastoid recruits briskly during the flexion phase of the upper cervical flexion movement, whereas the cervical paraspinals recruit briskly during return to mid-line when the lower cervical flexion is used. The combined upper then lower cervical flexion movement recruits both sets of muscles.ConclusionsThe results of the study indicate 2 distinct movement patterns associated with upper versus lower cervical flexion and 2 distinct sEMG recruitment patterns. The study suggests that these 2 distinct movements involve 2 distinct cervical segments and are associated with recruitment of different muscle groups. Applied clinical research on the cervical spine should use sEMG recordings to assess both the upper and lower flexion movements as the standard for the study of cervical flexion.

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