Age and gender differences in the mechanical properties of the upper trapezius muscle among patients with chronic neck pain: a pilot study

Abstract

Abstract The impact of age and gender on the characteristics of the upper trapezius muscle in patients with chronic neck pain(CNP) has not been previously documented. Age- and sex-related alterations in upper trapezius(UT) muscle characteristics may play a important role in the development of CNP. To investigate the relationship between muscle characteristics of the UT on both sides (unaffected and affected) and age and gender in patients with CNP and analyzed the correlation between muscular imbalance and VAS scores as well as BMI index in patients. A total of 160 unilateral CNP patients meeting the inclusion and exclusion criteria were selected according to age and gender. They were divided into 8 groups according to age and gender: 20 to 29 years old, 30 to 39 years old, 40 to 49 years old, and 50 to 59 years old. There were 20 male and 20 female in each age group. Muscle tone and stiffness of the UT on the unaffected and affected sides were assessed using MyotonPRO in all participants. Age - and sex-related factors had significant effects on both unaffected and affected UT muscle tone and stiffness in patients with unilateral CNP, with greater prominence observed on the affected side compared to the unaffected side, but no interaction between age and gender was observed. Regarding the unaffected UT, the muscle tone and stiffness of middle-aged and elderly group༈MEG༉ participants were significantly higher than those of middle-aged group ༈MG༉participants ( P < 0.01 ), and MG participants were significantly higher than those of middle-young participants group (MYG) participants ( P < 0.05 ), but no significant difference in muscle tone and stiffness between MYG participants and young group (YG) participants ( P > 0.05 ). There were no significant differences in muscle tone and stiffness between males and females in the YG ( P > 0.05 ), but there were significant differences among MYG, MG and MEG. The UT of the affected side exhibited significant variations in muscle tension and stiffness across all groups, with a consistent trend observed: MEG > MG > MYG > YG. Furthermore, it was found that males in all groups displayed significantly higher levels of muscle tone and stiffness compared to females (P < 0.05). In addition, the UT muscle tone asymmetry index and stiffness asymmetry index of all groups exhibited a significant positive correlation with VAS scores, but not significantly correlated with BMI. These findings provide a valuable dataset for understanding muscle tone and stiffness in the UT among CNP patients aged 20–59 years, offering insights for prevention and treatment strategies for CNP.