Adduction and Infraspinatus Activity in Shoulder Pain

NCT07765056 | Completed

• 1 other identifier: DI20-0046
• Study Type: interventional
• Target: 44
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this randomized crossover trial is to determine whether different levels of shoulder adduction pressure during an external rotation exercise change shoulder muscle activity in adults with chronic shoulder pain and adults without shoulder pain. The main question is whether adding a small amount of shoulder adduction pressure increases activity of the infraspinatus muscle without increasing activity of the deltoid muscles. Researchers will compare three levels of adduction pressure (0, 5, and 10 mmHg) during the same external rotation exercise. Participants will perform the three exercise conditions in a randomly assigned order while researchers measure shoulder muscle activity using surface electromyography.

Conditions

Chronic Shoulder Pain

Keywords

Electromyography; Muscle activation; Musculoskeletal pain; Neuromuscular control; Rotator cuff; Shoulder rehabilitation; Therapeutic exercise; Infraspinatus; Shoulder external rotation; Shoulder adduction

Outcome Measures

Primary Outcomes (1)

• Peak Surface Electromyographic Activity of Shoulder Muscles

  Peak surface electromyographic activity of the anterior deltoid, middle deltoid, posterior deltoid, infraspinatus, latissimus dorsi, and middle trapezius during the shoulder external rotation exercise. Electromyographic activity was normalized to the maximum voluntary isometric contraction (MVIC) and expressed as a percentage of MVIC.

  Day 1. During each experimental condition (0, 5, and 10 mmHg)

Study Arms (6)

Sequence 1: 0-5-10 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 0 mmHg, 5 mmHg, and 10 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Sequence 2: 0-10-5 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 0 mmHg, 10 mmHg, and 5 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Sequence 3: 5-0-10 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 5 mmHg, 0 mmHg, and 10 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Sequence 4: 5-10-0 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 5 mmHg, 10 mmHg, and 0 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Sequence 5: 10-0-5 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 10 mmHg, 0 mmHg, and 5 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Sequence 6: 10-5-0 mmHg

EXPERIMENTAL

Participants assigned to this sequence performed the shoulder external rotation exercise under 10 mmHg, 5 mmHg, and 0 mmHg of shoulder adduction pressure, respectively.

Behavioral: Shoulder External Rotation With 0 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 5 mmHg Adduction Pressure; Behavioral: Shoulder External Rotation With 10 mmHg Adduction Pressure

Interventions

Shoulder External Rotation With 0 mmHg Adduction Pressure BEHAVIORAL

Participants performed the shoulder external rotation exercise while maintaining 0 mmHg of isometric shoulder adduction pressure against a biofeedback wedge. The exercise was performed with the shoulder positioned at approximately 45 degrees of external rotation from 0 degrees of glenohumeral rotation.

Sequence 1: 0-5-10 mmHg; Sequence 2: 0-10-5 mmHg; Sequence 3: 5-0-10 mmHg; Sequence 4: 5-10-0 mmHg; Sequence 5: 10-0-5 mmHg; Sequence 6: 10-5-0 mmHg

Shoulder External Rotation With 5 mmHg Adduction Pressure BEHAVIORAL

Participants performed the shoulder external rotation exercise while maintaining 5 mmHg of isometric shoulder adduction pressure against a biofeedback wedge. The exercise was performed with the shoulder positioned at approximately 45 degrees of external rotation from 0 degrees of glenohumeral rotation.

Sequence 1: 0-5-10 mmHg; Sequence 2: 0-10-5 mmHg; Sequence 3: 5-0-10 mmHg; Sequence 4: 5-10-0 mmHg; Sequence 5: 10-0-5 mmHg; Sequence 6: 10-5-0 mmHg

Shoulder External Rotation With 10 mmHg Adduction Pressure BEHAVIORAL

Participants performed the shoulder external rotation exercise while maintaining 10 mmHg of isometric shoulder adduction pressure against a biofeedback wedge. The exercise was performed with the shoulder positioned at approximately 45 degrees of external rotation from 0 degrees of glenohumeral rotation.

Sequence 1: 0-5-10 mmHg; Sequence 2: 0-10-5 mmHg; Sequence 3: 5-0-10 mmHg; Sequence 4: 5-10-0 mmHg; Sequence 5: 10-0-5 mmHg; Sequence 6: 10-5-0 mmHg

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Shoulder Pain Group (SPG):
• Adults aged 18 years or older.
• Medical diagnosis of chronic non-traumatic shoulder pain lasting more than 3 months.
• Resting pain intensity of at least 2 cm on a visual analogue scale (VAS).
• Ability to perform at least 130° of shoulder flexion, 90° of shoulder abduction, and 45° of shoulder external rotation.
• Pain-Free Group (PFG):
• Adults aged 18 years or older.
• No current shoulder or neck symptoms.
• No shoulder or neck symptoms during the previous 2 years.
• No previous medical consultation for shoulder or neck discomfort.
• Full shoulder abduction and external rotation range of motion.
• Ability to perform pain-free maximal isometric contractions during shoulder abduction and external rotation.

You may not qualify if:

• Shoulder Pain Group (SPG):
• History of neck or upper limb surgery.
• History of glenohumeral instability or upper limb fracture.
• Neck pain or pain in another segment of the upper limb.
• Systemic diseases that could influence shoulder movement or muscle activation, including rheumatoid arthritis or neuromuscular diseases.
• Physical therapy treatment during the previous year for pain in the affected upper limb.

Sponsors & Collaborators

• Universidad de La Frontera: lead

Study Sites (1)

Universidad de La Frontera

Temuco, La Araucanía, Chile

Location

Related Publications (1)

• Bascour-Sandoval, Claudio, Gajardo-Burgos, Rubén, Gálvez-García, Germán, & Barramuño-Medina, Mauricio. (2021). Effect of Adduction During Glenohumeral External Rotation Exercises in the Scapulohumeral Muscles. International Journal of Morphology, 39(5), 1316-1322. https://dx.doi.org/10.4067/S0717-95022021000501316

  BACKGROUND

MeSH Terms

Conditions

Musculoskeletal Pain

Condition Hierarchy (Ancestors)

Muscular Diseases; Musculoskeletal Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Germán Gálvez García, PhD

  Universidad de La Frontera

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: OTHER
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Doctor

Model Details: This randomized crossover trial included two clinical comparison groups: participants with chronic shoulder pain and pain-free participants. Within each group, participants were randomly assigned to one of six possible sequences of three experimental conditions involving 0, 5, and 10 mmHg of shoulder adduction pressure during the external rotation exercise. Each participant completed all three experimental conditions. Peak muscle activity was recorded using surface electromyography.

Study Record Dates

• First Submitted: August 9, 2026
• First Posted: August 14, 2026
• Study Start: August 1, 2023
• Primary Completion: August 1, 2024
• Study Completion: August 1, 2024
• Last Updated: August 14, 2026

Record last verified: 2026-08

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: The individual participant data and supporting information will become available beginning 12 months after publication of the study results and will remain available for 5 years.
• Access Criteria: Data will be available to qualified researchers who submit a scientifically sound research proposal for analyses that are consistent with the purpose of the original study. Requests will be reviewed by the study investigators. Access will be provided following approval of the request and completion of an appropriate data use agreement, where applicable. Researchers will be required to comply with applicable ethical, confidentiality, and data protection requirements.

Locations

CL (1)