Viscous Elastic Properties of Superficial Back Muscles in Individuals With Hyperkyphosis

Thoracic hyperkyphosis is a common spinal deformity that may alter the biomechanical and viscoelastic properties of trunk muscles. This comparative study aims to investigate differences in the mechanical properties of selected back and chest muscles between individuals with hyperkyphosis and healthy controls. A total of 88 participants will be categorized based on thoracic kyphosis angle (≥50° hyperkyphosis; \<50° control). The kyphosis angle will be measured using a flexible ruler method. Muscle tone, stiffness, elasticity, and relaxation properties of the trapezius, erector spinae, and pectoralis major muscles will be assessed using a handheld myotonometer. Spinal appearance perception will be evaluated using a kyphosis-specific questionnaire. The study is designed to examine whether differences exist in muscle mechanical properties and whether kyphosis severity is associated with asymmetry in viscoelastic muscle characteristics.