Patellofemoral Pain SyndromeVMO-PFPSNCT07562425
Effects of Isometric, Isotonic, and Eccentric VMO Exercises in Patellofemoral Pain Syndrome
A study testing Isometric VMO Exercise, Isotonic VMO Exercise and Eccentric VMO Exercise in people with Patellofemoral Pain Syndrome and Anterior Knee Pain, run by Firat University at 1 site in Turkey (Türkiye).
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Patellofemoral Pain Syndrome, Anterior Knee Pain
- What is being tested?
- Isometric VMO Exercise, Isotonic VMO Exercise and Eccentric VMO Exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 90 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 20 Aug 2026to 20 Nov 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Firat University
Elâzığ, MErkez, 23200
Muharrem Beydağı, PhD, 05323581105, fztgokhan@hotmail.com
Muhammet Şahin Elbastı, PhD
About this study
Official title: Comparison of the Effects of Isometric, Isotonic, and Eccentric Vastus Medialis Oblique Strengthening Exercises Applied in Terminal Knee Extension Range on Pain, Function, and Muscle Architecture in Individuals With Patellofemoral Pain Syndrome: A Randomized Controlled Trial
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.
Read more
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.
Read the detailed description
Patellofemoral pain syndrome (PFPS) is a prevalent condition affecting physically active individuals and is associated with anterior knee pain during functional activities. Alterations in patellofemoral joint biomechanics, particularly related to quadriceps muscle imbalance and insufficient activation of the vastus medialis oblique (VMO), are considered key contributing factors.
Although VMO strengthening is widely used in clinical practice, there is limited evidence comparing the effects of different contraction types-specifically isometric, isotonic, and eccentric exercises-applied within the terminal knee extension range (0-30°), where patellofemoral joint stress and stabilization demands are highest.
This study is designed as a three-arm, parallel-group, randomized controlled trial to investigate the comparative effects of these exercise modalities on pain, functional outcomes, and muscle architecture. The intervention period will last 8 weeks, with sessions conducted three times per week.
A total of 90 participants aged 18-40 years with clinically diagnosed PFPS will be recruited and randomly allocated into three groups: isometric, isotonic, and eccentric exercise groups. All participants will receive a standardized physiotherapy protocol including superficial heat application, transcutaneous electrical nerve stimulation (TENS), and therapeutic ultrasound prior to exercise.
Primary outcomes will include pain intensity assessed by the Visual Analog Scale (VAS) and functional status evaluated using the WOMAC index, 30-second sit-to-stand test, and stair ascent/descent test. Secondary outcomes will include ultrasonographic assessment of muscle architecture, including muscle thickness, fascicle length, pennation angle, and physiological cross-sectional area of the VMO muscle. Additionally, selected hip muscles (adductor group and tensor fascia lata) will be evaluated.
Assessments will be performed at baseline (T0) and after the 8-week intervention (T1) by a blinded assessor. Randomization will be conducted using a computer-generated sequence with allocation concealment.
Statistical analyses will include repeated measures analysis to evaluate within-group and between-group differences, with significance set at p < 0.05.
The findings of this study are expected to contribute to evidence-based rehabilitation by identifying the most effective type of VMO strengthening exercise for improving clinical outcomes and muscle structure in individuals with PFPS.
- Conditions
- Patellofemoral Pain Syndrome, Anterior Knee Pain
- Being tested
- Isometric VMO Exercise, Isotonic VMO Exercise, Eccentric VMO Exercise
- Keywords
- Vastus Medialis Oblique, Knee Pain, Exercise Therapy, Isometric Exercise, Isotonic Exercise, Eccentric Exercise, Muscle Architecture
- Medical subject headings
- Patellofemoral Pain Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Isometric VMO ExerciseOther
Also called Experimental: Isometric Exercise Group
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.
Isotonic VMO ExerciseOther
Participants will perform controlled concentric and eccentric contractions using ankle weights through a limited range of motion (0-30° knee extension).
Eccentric VMO ExerciseOther
Participants will perform eccentric contractions against resistance during knee flexion, with assisted concentric return to the starting position.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: 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. Receives: Other: Eccentric VMO Exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: Baseline and Week 8
Secondary outcomes (5)
Pain Intensity (Visual Analog Scale, VAS)
Pain intensity will be assessed using the Visual Analog Scale (VAS), a 10-cm scale ranging from 0 (no pain) to 10 (worst imaginable pain). Higher scores indicate greater pain intensity.
Measured: Baseline and Week 8
Functional Status (WOMAC Index)
Functional status will be evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), including pain, stiffness, and physical function subscales. Higher scores indicate worse functional status.
Measured: Baseline and Week 8
30-Second Sit-to-Stand Test
The number of repetitions completed in 30 seconds will be recorded to assess lower extremity functional strength.
Measured: Baseline and Week 8
Stair Ascent and Descent Test
Time required to ascend and descend a standardized 9-step staircase will be recorded in seconds.
Measured: Baseline and Week 8
Hip Muscle Architecture (Ultrasound)
Muscle architecture parameters of the hip muscles (adductors and tensor fascia lata) will be evaluated using ultrasound imaging.
Measured: Baseline and Week 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 May 2026
- Study start20 Aug 2026 (estimated)
- Primary completion20 Nov 2026 (estimated)
- Study completion20 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Patellofemoral Pain SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- 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.
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 90 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Firat University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Muharrem Gökhan Beydağı, Firat University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07562425
- Sponsor's protocol ID
- FU_MGBeydagi_PFAS_B_2026/05
- Acronym
- VMO-PFPS
- Status last verified
- Aug 2026
- First submitted
- 27 Apr 2026
- Last updated
- 11 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 11 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of the Effects of Isometric, Isotonic, and Eccentric Vastus Medialis Oblique Strengthening Exercises Applied in Terminal Knee Extension Range on Pain, Function, and Muscle Architecture in Individuals With Patellofemoral Pain Syndrome: A Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07562425
- Acronym / sponsor ID
- VMO-PFPS / FU_MGBeydagi_PFAS_B_2026/05
- Conditions
- Patellofemoral Pain Syndrome, Anterior Knee Pain
- Keywords
- Vastus Medialis Oblique, Knee Pain, Exercise Therapy, Isometric Exercise, Isotonic Exercise, Eccentric Exercise, Muscle Architecture
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 90 participants (estimated)
- Lead sponsor
- Firat UniversityUniversity, hospital or other
- Study start
- 20 Aug 2026 (estimated)
- Primary completion
- 20 Nov 2026 (estimated)
- Study completion
- 20 Nov 2026 (estimated)
- First posted
- 1 May 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
Patellofemoral pain syndrome (PFPS) is a prevalent condition affecting physically active individuals and is associated with anterior knee pain during functional activities. Alterations in patellofemoral joint biomechanics, particularly related to quadriceps muscle imbalance and insufficient activation of the vastus medialis oblique (VMO), are considered key contributing factors.
Although VMO strengthening is widely used in clinical practice, there is limited evidence comparing the effects of different contraction types-specifically isometric, isotonic, and eccentric exercises-applied within the terminal knee extension range (0-30°), where patellofemoral joint stress and stabilization demands are highest.
This study is designed as a three-arm, parallel-group, randomized controlled trial to investigate the comparative effects of these exercise modalities on pain, functional outcomes, and muscle architecture. The intervention period will last 8 weeks, with sessions conducted three times per week.
A total of 90 participants aged 18-40 years with clinically diagnosed PFPS will be recruited and randomly allocated into three groups: isometric, isotonic, and eccentric exercise groups. All participants will receive a standardized physiotherapy protocol including superficial heat application, transcutaneous electrical nerve stimulation (TENS), and therapeutic ultrasound prior to exercise.
Primary outcomes will include pain intensity assessed by the Visual Analog Scale (VAS) and functional status evaluated using the WOMAC index, 30-second sit-to-stand test, and stair ascent/descent test. Secondary outcomes will include ultrasonographic assessment of muscle architecture, including muscle thickness, fascicle length, pennation angle, and physiological cross-sectional area of the VMO muscle. Additionally, selected hip muscles (adductor group and tensor fascia lata) will be evaluated.
Assessments will be performed at baseline (T0) and after the 8-week intervention (T1) by a blinded assessor. Randomization will be conducted using a computer-generated sequence with allocation concealment.
Statistical analyses will include repeated measures analysis to evaluate within-group and between-group differences, with significance set at p < 0.05.
The findings of this study are expected to contribute to evidence-based rehabilitation by identifying the most effective type of VMO strengthening exercise for improving clinical outcomes and muscle structure in individuals with PFPS.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
- Model description
- 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.
| Arm | Type | Receives |
|---|---|---|
| Isometric Exercise Group | Experimental | Other: Isometric VMO ExerciseParticipants 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. |
| Isotonic Exercise Group | Experimental | Other: Isotonic VMO ExerciseParticipants 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. |
| Eccentric Exercise Group | Experimental | Other: Eccentric VMO ExerciseParticipants 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. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- 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)
Key exclusion criteria (7 listed)
- History of knee trauma or surgery
- Meniscal injury, ligament injury, or knee instability
- Advanced osteoarthritis
- Neurological disorders
- Rheumatologic diseases
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Isometric VMO ExerciseAlso: Experimental: Isometric Exercise GroupIsometric 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. | Other | Isometric Exercise Group |
| Isotonic VMO ExerciseParticipants will perform controlled concentric and eccentric contractions using ankle weights through a limited range of motion (0-30° knee extension). | Other | Isotonic Exercise Group |
| Eccentric VMO ExerciseParticipants will perform eccentric contractions against resistance during knee flexion, with assisted concentric return to the starting position. | Other | Eccentric Exercise Group |
Primary outcome
VMO Muscle Architecture (Ultrasound)
Time frame: Baseline and Week 8
Muscle thickness, fascicle length, pennation angle, and physiological cross-sectional area of the vastus medialis oblique muscle will be assessed using ultrasound imaging.
5 secondary outcomes
Pain Intensity (Visual Analog Scale, VAS)
Time frame: Baseline and Week 8
Functional Status (WOMAC Index)
Time frame: Baseline and Week 8
30-Second Sit-to-Stand Test
Time frame: Baseline and Week 8
Stair Ascent and Descent Test
Time frame: Baseline and Week 8
Hip Muscle Architecture (Ultrasound)
Time frame: Baseline and Week 8
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 11 Aug 2026.
- Individual participant dataSharing planned: No
Related trials for Patellofemoral Pain Syndrome
Recruiting
Effects of Telerehabilitation Versus Supervised Rehabilitation Protocol on Pain, Range of Motion and Functional Recovery in Patients With Patellofemoral Pain Syndrome.
Patello Femoral Pain Syndrome
RecruitingObservational study
MRI Study of Musculoskeletal Function
Abnormalities, Imaging
Not yet recruiting
Comparison of High-Intensity and Conventional Physical Therapy in Musculoskeletal Disorders
Low Back Pain, Radicular Syndrome
Active, not recruiting
Stabilization vs Corrective Exercise in PFP
Patellofemoral Pain Syndrome
Not yet recruiting
Effectiveness of Selected Traditional Chinese Medicine Topical Agents on Long Distance Runner Versus Exercise Therapy as Control for Patellofemoral Pain Syndrome
Patellar Femoral Syndrome, TCMO (Ng's Prescription)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Isometric VMO Exercise, Isotonic VMO Exercise and Eccentric VMO Exercise in people with Patellofemoral Pain Syndrome and Anterior Knee Pain, run by Firat University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 11 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Muharrem Gökhan Beydağı, PhD (+905323581105, mgbeydagi@firat.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
VMO Muscle Architecture (Ultrasound) (time frame: Baseline and Week 8). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Aug 2026.