Effects of Isometric, Isotonic, and Eccentric VMO Exercises in Patellofemoral Pain Syndrome

NCT07562425 | Not Yet Recruiting

• 1 other identifier: FU_MGBeydagi_PFAS_B_2026/05
• Study Type: interventional
• Target: 90
• Locations: 1 country
• Sites: 1

Brief Summary

Patellofemoral pain syndrome (PFPS) is a common musculoskeletal condition characterized by anterior knee pain, especially during activities such as stair climbing, squatting, running, and prolonged sitting. Weakness or delayed activation of the vastus medialis oblique (VMO) muscle is considered an important contributing factor in the development of PFPS. This study aims to compare the effects of three different types of VMO strengthening exercises (isometric, isotonic, and eccentric) applied within the terminal knee extension range (0-30°) on pain, functional performance, and muscle architecture in individuals with PFPS. Participants will be randomly assigned to one of three exercise groups. All participants will receive a standardized physiotherapy program, including heat therapy, TENS, and therapeutic ultrasound, followed by group-specific VMO strengthening exercises. The intervention will be performed three times per week for 8 weeks. Outcomes will be assessed before and after the intervention and will include pain intensity (Visual Analog Scale), functional performance (WOMAC, 30-second sit-to-stand test, and stair test), and muscle architecture parameters measured by ultrasound imaging. The results of this study are expected to provide evidence for optimizing rehabilitation strategies in individuals with PFPS.

Conditions

Patellofemoral Pain Syndrome; Anterior Knee Pain

Keywords

Vastus Medialis Oblique; Knee Pain; Exercise Therapy; Isometric Exercise; Isotonic Exercise; Eccentric Exercise; Muscle Architecture

Outcome Measures

Primary Outcomes (1)

• VMO Muscle Architecture (Ultrasound)

  Muscle thickness, fascicle length, pennation angle, and physiological cross-sectional area of the vastus medialis oblique muscle will be assessed using ultrasound imaging.

  Baseline and Week 8

Secondary Outcomes (5)

• Pain Intensity (Visual Analog Scale, VAS)

  Baseline and Week 8

• Functional Status (WOMAC Index)

  Baseline and Week 8

• 30-Second Sit-to-Stand Test

  Baseline and Week 8

• Stair Ascent and Descent Test

  Baseline and Week 8

• Hip Muscle Architecture (Ultrasound)

  Baseline and Week 8

Study Arms (3)

Isometric Exercise Group

EXPERIMENTAL

Participants in this group will receive a standardized physiotherapy program (hot pack, TENS, and therapeutic ultrasound) followed by isometric VMO strengthening exercises performed in the terminal knee extension range (0-30°). Exercises will be performed 3 sets of 10 repetitions, with 10-second contractions, three times per week for 8 weeks.

Other: Isometric VMO Exercise

Isotonic Exercise Group

EXPERIMENTAL

Participants will receive the same standardized physiotherapy program followed by isotonic (concentric and eccentric) VMO strengthening exercises performed within the 0-30° knee extension range using external resistance. Exercises will be performed 3 sets of 10-15 repetitions, three times per week for 8 weeks.

Other: Isotonic VMO Exercise

Eccentric Exercise Group

EXPERIMENTAL

Participants will receive the same standardized physiotherapy program followed by eccentric VMO strengthening exercises performed within the 0-30° knee extension range. Exercises will be performed 3 sets of 10-15 repetitions, three times per week for 8 weeks.

Other: Eccentric VMO Exercise

Interventions

Isometric VMO Exercise OTHER

Isometric contractions of the vastus medialis oblique muscle will be performed with the knee supported at approximately 15° flexion, emphasizing maximal voluntary contraction without joint movement.

Also known as: Experimental: Isometric Exercise Group

Isometric Exercise Group

Isotonic VMO Exercise OTHER

Participants will perform controlled concentric and eccentric contractions using ankle weights through a limited range of motion (0-30° knee extension).

Isotonic Exercise Group

Eccentric VMO Exercise OTHER

Participants will perform eccentric contractions against resistance during knee flexion, with assisted concentric return to the starting position.

Eccentric Exercise Group

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Aged between 18 and 40 years
• Clinically diagnosed with patellofemoral pain syndrome
• Presence of anterior knee pain for at least 3 months
• Pain during activities such as stair climbing, squatting, running, or prolonged sitting
• Pain intensity of at least 3/10 on the Visual Analog Scale (VAS)
• Willingness to participate and provide written informed consent

You may not qualify if:

• History of knee trauma or surgery
• Meniscal injury, ligament injury, or knee instability
• Advanced osteoarthritis
• Neurological disorders
• Rheumatologic diseases
• Participation in a structured knee rehabilitation program within the last 6 months
• Pregnancy

Sponsors & Collaborators

• Firat University: lead

Study Sites (1)

Firat University

Elâzığ, MErkez, 23200, Turkey (Türkiye)

Location

MeSH Terms

Conditions

Patellofemoral Pain Syndrome

Condition Hierarchy (Ancestors)

Joint Diseases; Musculoskeletal Diseases

Central Study Contacts

Muharrem Gökhan Beydağı, PhD

CONTACT

+905323581105; mgbeydagi@firat.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Outcome assessments will be performed by a physiotherapist who is blinded to group allocation.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor, PhD

Model Details: Participants will be randomly assigned to three parallel groups receiving isometric, isotonic, or eccentric VMO strengthening exercises in addition to a standardized physiotherapy program for 8 weeks.

Study Record Dates

• First Submitted: April 27, 2026
• First Posted: May 1, 2026
• Study Start (Estimated): May 20, 2026
• Primary Completion (Estimated): June 20, 2026
• Study Completion (Estimated): August 1, 2026
• Last Updated: May 1, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)