Supraspinatus Tendon Acute Effects After Two Exercise Exposures: a Crossover Randomized Trial.

The purpose of this study is to understand acute tendon changes after two exercise programs. We will invite individuals with and without shoulder pain to participate in this study. Every individual will participate in both exercise programs separated by up to 15 days. The researcher will evaluate the shoulder tendon using ultrasound before each exercise program and at 1 hour, 6 hours and 24 hours after each exercise program. The researcher will also evaluate self reported pain, pain sensitivity testing, and self reported questionnaires. We will compare the tendon changes after each exercise program, as well as between participants with and without shoulder pain.

Study Overview

• Status: Recruiting
• Conditions: Shoulder Pain; Healthy Adult
• Intervention / Treatment: Behavioral: Isotonic exercise program; Behavioral: Plyometric exercise program

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ignacio A Raguzzi, PT; Phone Number: 352-665-4947; Email: iraguzzi@ufl.edu

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32610
      • Recruiting
      • University of Florida
      • Contact: Federico Pozzi, PT, MA, PhD; Phone Number: 352-273-6957; Email: fpozzi@phhp.ufl.edu
      • Principal Investigator: Ignacio A Raguzzi, PT

Participation Criteria

Eligibility Criteria

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

Description

General inclusion criteria

1. Between 18 and 45 years of age
2. Able to perform physical activity with their shoulder (moderate arm exercise for 15 min, such as tennis or housework)

General exclusion criteria

1. Shoulder fracture
2. Frozen shoulder (>50% restriction in shoulder range of motion)
3. Shoulder surgery
4. Full rotator-cuff tears
5. Bilateral shoulder pain
6. Shoulder instability (history or positive apprehension test)
7. Corticosteroid injection in the last 6 weeks
8. Neurological diseases
9. Cardiological diseases
10. Systemic diseases (rheumatic diseases, autoimmune diseases)
11. Uncontrolled diabetes
12. Pregnancy

Group-specific inclusion criteria

1. Shoulder pain group: report unilateral shoulder pain with an average shoulder pain score of≥ 3 in the last week.
2. Control group: report no shoulder pain within 6 months.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Isotonic exercise then Plyometric exercise	Behavioral: Isotonic exercise program; Participants will perform two isotonic exercises, prone shoulder external rotation and shoulder elevation. The exercises will be performed at a pace of 2-second for both concentric and eccentric phases. For each exercise, participants will perform two sets of 8 repetitions, followed by a third set performed until fatigue. Fatigue will be determined using the Repetition in Reserve Scale, which asks the participant to perform exercises until they reach a self-selected number corresponding to the number of repetitions left that a participant could still complete if needed. We will ask participants to continue the third set until they reach a Repetition in Reserve number of 1. The rest period will be 30 seconds between sets and 2 minutes between exercises. The exercise load will be selected after manual maximal isometric strength testing using a handheld dynamometer. A 40% of the strength testing will be used for exercises in both groups following strength guidelines.; Behavioral: Plyometric exercise program; Participants will perform two isotonic exercises, prone shoulder external rotation and shoulder elevation. The exercises will be performed at a pace of 1-second for the eccentric phases followed by an explosive concentric phase. For each exercise, participants will perform two sets of 8 repetitions, followed by a third set performed until fatigue. Fatigue will be determined using the Repetition in Reserve Scale, which asks the participant to perform exercises until they reach a self-selected number corresponding to the number of repetitions left that a participant could still complete if needed. Participants will complete the third set until they reach a Repetition in Reserve number of 1. The rest period will be 30 seconds between sets and 2 minutes between exercises. The exercise load will be selected after manual maximal isometric strength testing using a handheld dynamometer. A 40% of the strength testing will be used for exercises in both groups following strength guidelines.
Experimental: Plyometric exercise then Isotonic exercise	Behavioral: Isotonic exercise program; Participants will perform two isotonic exercises, prone shoulder external rotation and shoulder elevation. The exercises will be performed at a pace of 2-second for both concentric and eccentric phases. For each exercise, participants will perform two sets of 8 repetitions, followed by a third set performed until fatigue. Fatigue will be determined using the Repetition in Reserve Scale, which asks the participant to perform exercises until they reach a self-selected number corresponding to the number of repetitions left that a participant could still complete if needed. We will ask participants to continue the third set until they reach a Repetition in Reserve number of 1. The rest period will be 30 seconds between sets and 2 minutes between exercises. The exercise load will be selected after manual maximal isometric strength testing using a handheld dynamometer. A 40% of the strength testing will be used for exercises in both groups following strength guidelines.; Behavioral: Plyometric exercise program; Participants will perform two isotonic exercises, prone shoulder external rotation and shoulder elevation. The exercises will be performed at a pace of 1-second for the eccentric phases followed by an explosive concentric phase. For each exercise, participants will perform two sets of 8 repetitions, followed by a third set performed until fatigue. Fatigue will be determined using the Repetition in Reserve Scale, which asks the participant to perform exercises until they reach a self-selected number corresponding to the number of repetitions left that a participant could still complete if needed. Participants will complete the third set until they reach a Repetition in Reserve number of 1. The rest period will be 30 seconds between sets and 2 minutes between exercises. The exercise load will be selected after manual maximal isometric strength testing using a handheld dynamometer. A 40% of the strength testing will be used for exercises in both groups following strength guidelines.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Supraspinatus tendon thickness	The investigators will use ultrasound to take pictures of the supraspinatus tendons. Established ultrasound procedures will be used to measure supraspinatus tendon thickness.	From enrollment to 1 hour, 6 hours, and 24 hours after each exercise program.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain sensitivity testing	The investigators will apply pressure at a constant rate using a computerized pressure algometer with a 1 cm diameter rubber tip at the shoulder and the lower limb.	From enrollment to 1 hour, 6 hours, and 24 hours after each exercise program.
Self-reported pain	We will use an 11-point numeric pain rating scale to measure the shoulder pain perceived by the participant.	From enrollment to 1, 6, and 24 hours after each exercise program.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of perceived exertion	We will use a 11-point scale, 0 being no effort and 10 being the maximal effort, to understand the effort perceived after each exercise program.	Immediately after each exercise program.
Pennsylvania Shoulder Score (PENN)	The PENN is a valid and reliable self-reported questionnaire for patients with shoulder pain.	At baseline before each exercise program.
Optimal Screening for Prediction of Referral and Outcome (OSPRO)	The OSPRO is a concise, multidimensional 10-item yellow flag assessment tool that estimates 11 total questionnaire scores indicating elevated vulnerability and decreased resilience.	At baseline before the first exercise program.
Global rating of change (GROC)	The GROC is a rating scale that quantifies participants' improvement or deterioration of symptoms over time. Changes will be measured using a 15-points Likert scale (-7, a very great deal worse to 7, a very great deal better, with 0 indicating no changes).	At the second baseline before the second exercise program at 1 week.
Tegner Activity Scale	Is a valid and reliable tool that evaluates work and sport participation. It addresses both function and activity level, and it will provide information about the physical general activity of the individual.	At baseline before the first exercise program.
Rate of perceived fatigue	We will use a 11-point scale, 0 being no fatigue and 10 being the maximal fatigue, to understand the fatigue perceived after each exercise program.	Immediately after each exercise program
Self-reported pain related to the exercise	We will use an 11-point numeric pain rating scale to measure the shoulder pain perceived by the participant.	Before and immediately after each exercise program
Muscle soreness	We will use an 11-point numeric rating scale to measure the muscle soreness perceived by the participant after the exercise.	Before and immediately, 1, 6 and 24 hours after each exercise program

Collaborators and Investigators

• Sponsor: University of Florida

Study record dates

Study Major Dates

• Study Start (Actual): April 20, 2026
• Primary Completion (Estimated): April 1, 2027
• Study Completion (Estimated): April 1, 2027

Study Registration Dates

• First Submitted: March 18, 2026
• First Submitted That Met QC Criteria: March 18, 2026
• First Posted (Actual): March 24, 2026

Study Record Updates

• Last Update Posted (Actual): April 22, 2026
• Last Update Submitted That Met QC Criteria: April 21, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: exercise; ultrasound; shoulder pain; rotator cuff tendinopathy; subacromial pain; rotator cuff related shoulder pain; tendon thickness
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Joint Diseases; Arthralgia; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Shoulder Pain; Motor Activity
• Other Study ID Numbers: IRB202501875

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Time Frame: Study protocol & statistical analysis plan: A manuscript describing the study protocol and statistical analysis plan will be submitted for publication before the end of the recruitment for the study.
• IPD Sharing Access Criteria: Study protocol and statistical analysis plan: The manuscript will be published as open access.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

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