Sternocleidomastoid Muscle and Head Position: How to Minimize Muscle Tension

OCCUPATIONAL APPLICATIONS

The coronavirus disease pandemic has changed the setting of many jobs, forcing people to switch to remote work. In turn, telework is associated with an increased risk of musculoskeletal disorders, as it is difficult to ensure an ergonomically correct work environment at home. Complaints of headaches, neck pain, and dizziness are reported by both young and old people. One of the reasons for such complaints might be an incorrect head position and prolonged tension in the neck muscles that is directly correlated with a spatially misaligned computer monitor and peripherals. We examined biomechanical parameters of the sternocleidomastoid muscle and found that it is possible to reduce tension in this muscle by keeping the head in an appropriate angular range to minimize potential health risks.

TECHNICAL ABSTRACT

Background: With the increasing demand for faster data processing, computers and other smart devices have become an integral part of many workplaces. The sternocleidomastoid (SCM) muscle is one of the main muscles supporting the head. A review of the available literature suggested that overuse of this muscle can provoke a number of complaints among employees, including head and neck pain. This article describes effective head positioning angles to minimize SCM muscle strain.

Purpose: The main objective of this study was to determine how SCM muscle tension changes with head position angle. We hypothesized that the SCM muscle would demonstrate the least tension when the head is in a neutral position.

Methods: A total of 41 individuals (22 female, 19 male) participated. Only respondents without chronic conditions were included. SCM muscle tension was measured using a myotonometer.

Results: Strong positive correlations were observed between angle (head position) and SCM muscle tension (oscillation frequency) as well as between angle and SCM muscle stiffness. Negative correlations were found between head angle and SCM decrement (a measure of elasticity), and between head angle and SCM relaxation time.

Conclusions: Minimal tension in SCM muscle occurs when the head is positioned in flexion, at angles between −30° and −60°. Determining the angle of minimal SCM tension provides a foundation for further research and various technical solutions that may ensure such positioning (e.g., a monitor arm). However, to obtain more accurate insight into optimal positioning, simultaneous evaluation of multiple neck muscles should be completed in future work, and the neck extensor muscle group must be addressed.

Keywords:

• ergonomics
• monitor positioning
• myotonometry
• sternocleidomastoid muscle

Disclosure statement

No potential conflict of interest was reported by the authors.

Acknowledgments

The authors wish to thank Maija Gulajeva for her assistance in translation and we thank Linda Meire for making illustrations for this publication.

Additional information

Funding

This research was done as a part of Riga Stradiņš University vertically integrated project’s course “Ergonomic workplaces in a healthy environment” which is implemented as a part of ESF co-financed project Improvement of Governance Processes and Modernization of Contents of Study Programmes at Rīga Stradiņš University (No. 8.2.3.0/18/A/011).