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Assessment of the Stiffness of the Upper Trapezius Muscle in a Group of Asymptomatic People With Cervical Spine Rotation Asymmetry

Michał Wendt, Małgorzata Waszak


This study investigated the relationship between the stiffness of the upper trapezius muscle and the range of rotational movement of the cervical spine. A total of 60 right-handed asymptomatic students participated in the study. Participants (N = 22) characterised by asymmetry in rotational movements were selected for the experimental group. A difference of ≥10° between right and left rotation of the cervical spine was considered asymmetrical. The control group (N = 38) included participants whose rotation difference was < 10°. Belonging to the experimental or control group did not significantly differentiate trapezius muscle stiffness.


In recent years, research related to the assessment of biophysical parameters and their relationship with dysfunctions of the musculoskeletal system in many social groups exposed to various types of stress on muscles, tendons and joints has become more and more popular. For this purpose, researchers are increasingly using MyotonPRO. It is a relatively new hand-held device that allows characterising the biomechanical properties of superficial soft tissues in a simple and non-invasive way [1]. It works by applying a mechanical impulse to the skin, which is then transmitted to the underlying soft tissue and muscle [2]. The device allows you to test tone, stiffness and flexibility [3]. MyotonPRO can also measure other parameters of muscles, such as creep and viscoelastic stress relaxation [4].

Materials and method

The conducted study is classified as observational (case-control). The study design was based on Equatornetwork and STROBE checklist was used [23]. All measurements were carried out in the same place: Department of Biology and Anatomy of the Poznan University of Physical Education. During the measurements in the test room, the temperature was constant (23°C). The room was ventilated. Recruitment for this study began on April 13, 2020 and ended on May 4, 2020. A detailed description of the flow of participants through the individual phases of the study is presented in Fig 1.


The first research task was to determine the stiffness of the right and left trapezius muscles depending on the extent of the asymmetry of rotational movement and the side of restricted movement.


We found that the stiffness of the right and left trapezius muscles depended on the location of the muscle related to the range of rotational movement. In the experimental group (asymmetry of rotational movements ≥10°), the muscles on the side of limited (less) rotation of the cervical spine were significantly stiffer than the muscles on the side of greater rotation. The statistical analyses showed that limited rotation of the cervical spine is associated with increased stiffness of the trapezius muscle on the same side. It is probably related to the function of the upper trapezius muscle. In addition to affecting the shoulder girdle, this muscle rotates the cervical spine in the opposite direction [34]. Contraction of the upper right trapezius causes the cervical spine to rotate to the left. In this way, the muscle on the opposite side is stretched. Hence, increased stiffness of the upper trapezius, resulting from limited stretching of this muscle, may limit cervical spine rotation.


There is a relationship between the stiffness of the right and left upper trapezius muscles and the range of right and left rotational motion of the cervical spine.


The authors thank all participants for their cooperation during the research.

Citation: Wendt M, Waszak M (2024) Assessment of the stiffness of the upper trapezius muscle in a group of asymptomatic people with cervical spine rotation asymmetry. PLoS ONE 19(2): e0298544.

Editor: César Calvo-Lobo, Universidad Complutense de Madrid Escuela Universitaria de Enfermeria Fisioterapia y Podologia, SPAIN

Received: July 29, 2023; Accepted: January 25, 2024; Published: February 22, 2024

Copyright: © 2024 Wendt, Waszak. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The data is publicly available in the Figshare repository at the link below:

Funding: The author(s) received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.



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