Structure and Function of the Upper Trapezius and Its Role in Chronic Shoulder Pain: an Investigation of Kinematics, Morphology, Muscle Quality and Activation Distribution

Prior research has explored factors influencing muscle activation, including muscle thickness, fear avoidance beliefs (kinesiophobia), and somatosensory integration. In individuals with chronic shoulder pain, various characteristics impacting symptoms and treatment outcomes have been identified, such as psychosocial factors, fear avoidance, central sensitization, somatosensory impairments, and brain morphology changes. These shared characteristics affecting both muscle activation and chronic shoulder pain may potentially modulate upper trapezius muscle activation during functional movements in patients with chronic shoulder pain. Notably, there remains a gap in the literature concerning investigations into the upper trapezius muscle's morphology and quality, fear avoidance, central sensitization, somatosensory impairments, and their interplay with upper trapezius muscle activation in chronic shoulder pain patients.

To address these gaps, this study aims to: this study aims to: 1) compare different methods of measuring clavicular kinematics using an electromagnetic tracking system; 2) establish the reliability and validity of measuring muscle thickness and fat infiltration through ultrasound and magnetic resonance imaging; 3) compare shoulder kinematics, muscle activation, muscle morphology, and muscle fat infiltration in individuals with chronic shoulder pain with matched healthy controls; 4) explore the correlation between the factors that may influence upper trapezius muscle activation, including basic data of the subjects, muscle morphology, and muscle fat infiltration.

Study Overview

• Status: Recruiting
• Conditions: Chronic Shoulder Pain

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

Study Locations

• Taiwan
  • Taipei, Taiwan, 11221
    • Recruiting
    • National Yang Ming Chiao Tung University
    • Contact: Yi-Fen Shih, PhD; Phone Number: +886-2-2826-7340; Email: yfshih@ym.edu.tw

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Community Sample

Description

Inclusion Criteria:

• Chronic shoulder pain group

  • 18-50 years old18-50 years old
  • unilateral and non-traumatic shoulder pain
  • pain duration longer than 3 months
  • pain intensity more than VAS=2 during movement
  • presence 3 of 5 positive pain provocation tests: Hawkins-Kennedy test, Jobe test, or Neer's test Painful Arc, and Resistance Test against External Rotation.

• Healthy control group

  • presenting no shoulder pain at rest or during daily activities
  • negative results of the pain provocation test: Hawkins-Kennedy test, Jobe test, Neer's test, Painful Arc, Resistance Test against External Rotation and Spurling's neck compression test.

Exclusion Criteria:

- Chronic shoulder pain group

• history of significant shoulder trauma, such as fracture or ultrasonography clinically suspected full thickness cuff tear
• recent shoulder dislocation in the last 2 years
• diagnosis of adhesive capsulitis characterized by a gradual and painful loss of both active and passive ROM in all shoulder planes, primarily external rotation
• shoulder pain originating from the cervical spine by using Spurling's neck compression test
• shoulder pain owing to the following disorders: arthritis (e.g., rheumatoid arthritis, osteoarthritis of shoulder complex), neurologic (e.g., stroke), neoplastic (e.g., breast cancer). and/or referred pain (e.g., visceral referred pain)
• corticoid injections over the shoulder during 6 months prior to the study
• history of shoulder and neck surgery

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Healthy control group
Chronic shoulder pain group

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Shoulder kinematics	The scapular kinematics will be assessed, including scapular internal/external rotation, upward/downward rotation, and posterior/anterior tilt angle. Clavicular kinematics will be evaluated by measuring clavicular protraction/retraction, elevation/depression, and posterior rotation angle.	During the procedure
Muscle activation	The average root mean square (RMS) value collected from surface EMG and outcomes collected by high-density EMG including average root mean square (RMS) value in whole/upper/lower regions, the RMS value distribution, and position of the barycentre of RMS distribution in different humeral elevation angles and different isometric shoulder and scapular tasks will be the outcome measures related to muscle activation.	During the procedure

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Oscillation frequency	The oscillation frequency (Hz) of the muscle obtained from the myotonometer will represent the muscle tone	During the procedure
Dynamic stiffness	The dynamic stiffness (N/m) of the muscle obtained from the myotonometer will represent the muscle tone	During the procedure
Mechanical stress relaxation time (ms)	The mechanical stress relaxation time (ms) of the muscle obtained from the myotonometer will represent the muscle tone	During the procedure
Muscle thickness and cross-sectional area	The upper, middle and lower trapezius muscle thickness and cross-sectional area obtained from MRI and the upper, middle and lower trapezius muscle thickness obtained from musculoskeletal sonography.	During the procedure
Muscle thickness change at rest and in contraction	The muscle thickness at rest, during arm raise at 90o abduction, during 2-kg abduction, during 4-kg abduction, and the change (%) between the latter three and at rest.	During the procedure
Muscle fat quantification	The upper, middle and lower trapezius muscle fat quantification indicate the muscle fat infiltration.	During the procedure
Muscle / fat fraction	The upper, middle and lower trapezius muscle / fat fraction indicate the muscle fat infiltration.	During the procedure
Echo intensity	The echo intensity of the upper, middle and lower trapezius muscle obtained from the musculoskeletal sonography.	During the procedure
Pain intensity	The score obtained from the VAS scale and NRPS scale during the most painful movement represent the pain intensity of the chronic shoulder pain group.	During the procedure
Disability level	The FLEX-SF score and DASH score will indicate the disability level of the subjects.	During the procedure
Craniovertebral angle	The cranial-vertebral angle will indicate the level of forward head posture.	During the procedure

Collaborators and Investigators

• Sponsor: National Yang Ming Chiao Tung University

Study record dates

Study Major Dates

• Study Start (Actual): December 12, 2023
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: June 2, 2024
• First Submitted That Met QC Criteria: June 17, 2024
• First Posted (Actual): June 25, 2024

Study Record Updates

• Last Update Posted (Actual): April 14, 2026
• Last Update Submitted That Met QC Criteria: April 9, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Joint Diseases; Musculoskeletal Diseases; Arthralgia; Shoulder Pain
• Other Study ID Numbers: NYCU112175AE

Drug and device information, study documents

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