This study will examine whether extracorporeal shock wave therapy (ESWT) can reduce stiffness in the upper trapezius muscle. Muscle stiffness will be measured using a special ultrasound technique called shear-wave elastography (SWE), which allows researchers to assess changes in muscle properties. The aim of the study is to better understand if ESWT is effective in improving muscle function and reducing discomfort in this region. Healthy volunteers will be enrolled, and measurements will be taken before and after the ESWT treatment.

This interventional study investigates the acute effects of extracorporeal shock wave therapy (ESWT) on the mechanical properties of the upper trapezius muscle, with a specific focus on muscle stiffness. Stiffness will be quantified using shear-wave elastography (SWE), a non-invasive ultrasound-based imaging modality that allows for real-time assessment of tissue elasticity.

Participants will undergo baseline SWE measurements of the upper trapezius muscle, followed by the application of a standardized ESWT protocol. Post-treatment measurements will be conducted immediately after the intervention to evaluate acute changes in stiffness. The primary objective is to determine whether a single session of ESWT induces measurable changes in muscle mechanical properties.

This study will contribute to the growing body of evidence regarding the physiological effects of ESWT on skeletal muscle tissue and its potential application in clinical and sports settings. Data collected will also support the development of future longitudinal studies assessing the therapeutic relevance of ESWT for myofascial dysfunction and musculoskeletal pain syndromes.

Inclusion Criteria:

• Age between 18 and 45 years
• Healthy individuals with no current musculoskeletal or neurological disorders
• No history of neck or shoulder surgery
• Willingness to abstain from vigorous upper-body exercise 24 hours prior to -measurements

Exclusion Criteria:

• Presence of neck or shoulder pain within the past 3 months
• Diagnosed myofascial pain syndrome or fibromyalgia
• History of cervical spine injury or neurological conditions affecting upper limbs
• Use of analgesic or muscle relaxant medication within 48 hours prior to testing
• Pregnancy
• Contraindications to ESWT (e.g., bleeding disorders, pacemaker, malignancy in treatment area)