Influence of gender, skinfold thickness and body position on the biomechanical parameters of the trapezius muscle

S.K. Ivanova, H.P. Tancheva

Abstract: Introduction: The upper trapezius muscle, being a postural muscle is highly susceptible to overuse. The function of the trapezius is to stabilize and move the scapula but tightness in muscle reduces the range of neck movements as well as the mobility of cervical joints. The understanding of the biomechanical and viscoelastic stiffness of trapezius muscle is of interest in numerous fields such as health, sports, and physical activities. Objective: Knowing that muscles biomechanical properties are prerequisites for their function and can provide insight into muscle pathology, treatment progress and the sports form, we aimed to investigate the influence of gender, skin and subcutaneous tissue thickness (skinfold thickness, SFT) and body positions on biomechanical parameters of the trapezius muscle in order the obtained results to be used to optimize specific trainings or for rehabilitation purposes. Materials and methods: 183 right-handed undergraduate students (aged 19-24) participated. SFT was measured with a Lange® skinfold caliper, and upper trapezius biomechanical parameters were recorded in a relaxed seated position on both sides using a MyotonPro® myotonomeric device. Tree of the biomechanical parameters corresponds to biomechanical stiffness: frequency (F) in Hz, representing the tonus or state of active tension, dynamic stiffness (S) in N/m and decrement (D) (or elasticity). The other two represent viscoelastic stiffness: relaxation time (R) in ms and creep (C). In a subgroup of 90 students (40 males, 50 females), biomechanical parameters were also assessed in sitting, supine, prone, and side-lying positions. Analyses were conducted with SPSS v.19. Results: Males have significant higher values for F and S, and lower for D, R and C on both sides. SFT was significantly positive, correlating only with D on both sides. F and S have higher values in sitting position, followed by side lying to the opposite side, prone, and supine position. Generally, D, R and C exhibited opposite to F and S trend. Discussion and conclusions: MyotonPro® measurements indicate that males' upper trapezius muscles are stiffer, tenser, less deformable, and relax faster than females', while female muscles are more elastic. Skin and subcutaneous tissue depth may affect these readings, but further research is needed to confirm this. Muscle mechanical properties also vary with body position.

Series on Biomechanics, Vol.39, No.1(2025), 3-16
DOI: 10.7546/SB.01.03.2025

Keywords: gender; myoton; position; skinfold; trapezius muscle

DOI: 10.7546/SB.01.03.2025

Date published: 2025-10-28