Excessive use of smart devices and prolonged sitting posture in modern daily life can lead to potential hypertonicity and functional impairment of the upper trapezius even in healthy individuals. Such conditions may cause functional changes and discomfort before the onset of pain, and early intervention may help prevent the progression to musculoskeletal disorders. Therefore, this study aims to investigate the immediate effects of radial extracorporeal shock wave therapy (rESWT) applied simultaneously with stretching or isometric contraction on muscle tone, stiffness, thickness, pressure pain threshold, and grip strength of the upper trapezius in healthy adults. Participants will be divided into two groups : rESWT + stretching and rESWT + isometric contraction. Immediate changes in the upper trapezius will be compared before and after the interventions. rESWT will be applied to the upper trapezius with 1.0 bar pressure, 10 Hz frequency, and 1000 shocks.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
30
Participants will sit on a chair and receive rESWT with gel applied to the upper trapezius. A 20 mm rESWT applicator angled at 90° will be applied to the muscle belly and the musculotendinous junction. The intensity will be set at 1.0 bar pressure, 10 Hz frequency, with 1000 shocks. When rESWT is applied to the upper trapezius, participants will sit on a chair and repeatedly bend the neck diagonally to stretch the muscle, then return to the neutral position.
Participants will sit on a chair and receive rESWT with gel applied to the upper trapezius. A 20 mm rESWT applicator angled at 90° will be applied to the muscle belly and the musculotendinous junction. The intensity will be set at 1.0 bar pressure, 10 Hz frequency, with 1000 shocks. When rESWT is applied to the upper trapezius, participants will sit on a chair and maintain a shoulder elevation posture during the intervention.
73, Bungmun-daero 419beon-gil, Gwangju health university
Gwangju, South Korea
Muscle Tone
Upper trapezius muscle stiffness will be assessed as dynamic stiffness (N/m) using the MyotonPRO device (Myoton AS, Tallinn, Estonia). The probe will be positioned perpendicular to the skin over the belly of the upper trapezius muscle. After a pre-load of approximately 0.18 N, 10 mechanical impulses of approximately 0.4 N at 1 Hz will be delivered. Measurements will be repeated 3 times, and the mean value will be used for analysis. Change from baseline will be calculated as the immediate post-intervention value minus the baseline value.
Time frame: Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.
Muscle Stiffnes
Upper trapezius muscle stiffness will be assessed as dynamic stiffness (N/m) using the MyotonPRO device (Myoton AS, Tallinn, Estonia). The probe will be positioned perpendicular to the skin over the belly of the upper trapezius muscle. After a pre-load of approximately 0.18 N, 10 mechanical impulses of approximately 0.4 N at 1 Hz will be delivered. Measurements will be repeated 3 times, and the mean value will be used for analysis. Change from baseline will be calculated as the immediate post-intervention value minus the baseline value.
Time frame: Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.
Muscle Thickness
The probe of the ultrasound imaging device is placed perpendicular to the target area without applying any pressure after applying a water-based transmission gel, in order to measure muscle thickness. Then, using a 2.5 MHz ultrasound, strong echoes at tissue interfaces are focused, and the distance between the focused points is converted into millimeters to determine tissue thickness.
Time frame: Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.
Grip Strength
Grip strength is measured using a wireless dynamometer. The participant holds the dynamometer with the arm relaxed, the elbow flexed at 90°, the arm slightly away from the torso, and the wrist in a neutral position. Following the researcher's instructions, the participant exerts maximum force. The measurement is repeated three times, and the average value is recorded.
Time frame: Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.
Pressure Pain
The participant sits upright with the back supported by a wall or chair and feet flat on the floor. A pressure algometer with a 1 cm² rubber tip is placed perpendicular to the same muscle belly measured by the Myoton PRO. The researcher applies gradual pressure at a constant rate of 0.5 kg/cm²/s until the participant reports pain, and the value at the point of reported pain is recorded. The measurement is repeated twice, and the average value is used.
Time frame: Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.
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