Immediate Effects of Shock Wave Therapy With Stretching or Isometric Contraction on Upper Trapezius (rESWT)

The Immediate Effects of Simultaneous Application of Radial Extracorporeal Shock Wave Therapy and Stretching or Isometric Contraction on Muscle Tone, Stiffness, Thickness, Pressure Pain Threshold, and Grip Strength of the Upper Trapezius

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 Overview

• Status: Completed
• Conditions: Myofascial Pain Syndrome (MPS)
• Intervention / Treatment: Other: Radial Extracorporeal Shock Wave Therapy and Stretching; Other: Radial Extracorporeal Shock Wave Therapy and Isometric Contraction

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• South Korea
  • Gwangju, South Korea, 62287
    • 73, Bungmun-daero 419beon-gil, Gwangju health university

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Individuals with no history of neck or shoulder pain in the past 6 months
• Individuals with no history of upper limb musculoskeletal disorders
• Individuals with a pressure pain threshold (PPT) of the upper trapezius ≥ 263 kPa

Exclusion Criteria:

• Individuals with a history of neurological or orthopedic disorders
• Individuals taking medications that may affect ESWT response
• Individuals with local skin conditions, including ulcers or open wounds

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: experimental 1 group; Radial Extracorporeal Shock Wave Therapy and Stretching	Other: Radial Extracorporeal Shock Wave Therapy and Stretching; 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.
Active Comparator: experimental 2 group; Radial Extracorporeal Shock Wave Therapy and Isometric Contraction	Other: Radial Extracorporeal Shock Wave Therapy and Isometric Contraction; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	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.	Post-intervention measurement is conducted immediately after the intervention to assess immediate effects.

Collaborators and Investigators

• Sponsor: Sahmyook University

Study record dates

Study Major Dates

• Study Start (Actual): September 20, 2025
• Primary Completion (Actual): October 10, 2025
• Study Completion (Actual): October 25, 2025

Study Registration Dates

• First Submitted: December 11, 2025
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 27, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Stretching; ESWT; Upper Trapezius; Isometric Contraction
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Muscular Diseases; Myofascial Pain Syndromes; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Muscle Contraction; Isometric Contraction
• Other Study ID Numbers: SYU 2025-06-024-001

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No