ABSTRACT
Objective To survey cervical myoelectric signals during craniocervical flexion, neutral and extension postures, and to explore the evidence that proper head position can alleviate cervical muscle fatigue in a lateral recumbent position. Methods Surface electromyography (sEMG) signals were detected from the sternocleidomastoid, upper trapezius and erector spinae muscles of 30 young subjects bilaterally during craniocervical flexion,neutral and extension postures in the left lateral recumbent position. The integrated trace area (IEMG) and median frequency (MF) were estimated. Results The average IEMG of the sternocleidomastoid muscles was significantly lower in flexion than in extension bilaterally. The average IEMG of the erector spinae muscles was lower in extension than in flexion bilaterally, and the difference was again significant. The IEMGs of the upper trapezius muscle showed no significant difference on average in the three postures bilaterally. There was no significant MF difference in any of the muscles. Conclusions The muscles in the cervical back were less activated during craniocervical extension in a lateral recumbent position. A little cranicocervical extension is optimal while resting in a lateral recumbent position.