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Effects of Isometric, Isotonic, and Eccentric VMO Exercises in Patellofemoral Pain Syndrome (VMO-PFPS)

7 mai 2026 mis à jour par: Muharrem Gökhan Beydağı, Firat University

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.

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.

Aperçu de l'étude

Statut

Pas encore de recrutement

Les conditions

Intervention / Traitement

Description détaillée

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.

Type d'étude

Interventionnel

Inscription (Estimé)

90

Phase

  • N'est pas applicable

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Coordonnées de l'étude

Lieux d'étude

  • Turquie (Türkiye)
    • MErkez
      • Elâzığ, MErkez, Turquie (Türkiye), 23200
        • Firat University
        • Contact:
        • Chercheur principal:
          • Muhammet Şahin Elbastı, PhD

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte

Accepte les volontaires sains

Non

La description

Inclusion Criteria:

  • 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

Exclusion Criteria:

  • 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

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

  • Objectif principal: Traitement
  • Répartition: Randomisé
  • Modèle interventionnel: Affectation parallèle
  • Masquage: Seul

Armes et Interventions

Groupe de participants / Bras
Intervention / Traitement
Expérimental: Isometric Exercise Group
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.
Autre: Isometric VMO Exercise
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.
Autres noms:
  • Experimental: Isometric Exercise Group
Expérimental: Isotonic Exercise Group
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.
Autre: Isotonic VMO Exercise
Participants will perform controlled concentric and eccentric contractions using ankle weights through a limited range of motion (0-30° knee extension).
Expérimental: Eccentric Exercise Group
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.
Autre: Eccentric VMO Exercise
Participants will perform eccentric contractions against resistance during knee flexion, with assisted concentric return to the starting position.

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
VMO Muscle Architecture (Ultrasound)
Délai: 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.
Baseline and Week 8

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Pain Intensity (Visual Analog Scale, VAS)
Délai: Baseline and Week 8
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.
Baseline and Week 8
Functional Status (WOMAC Index)
Délai: Baseline and Week 8
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.
Baseline and Week 8
30-Second Sit-to-Stand Test
Délai: Baseline and Week 8
The number of repetitions completed in 30 seconds will be recorded to assess lower extremity functional strength.
Baseline and Week 8
Stair Ascent and Descent Test
Délai: Baseline and Week 8
Time required to ascend and descend a standardized 9-step staircase will be recorded in seconds.
Baseline and Week 8
Hip Muscle Architecture (Ultrasound)
Délai: Baseline and Week 8
Muscle architecture parameters of the hip muscles (adductors and tensor fascia lata) will be evaluated using ultrasound imaging.
Baseline and Week 8

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Firat University

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Estimé)

20 mai 2026

Achèvement primaire (Estimé)

20 juin 2026

Achèvement de l'étude (Estimé)

1 août 2026

Dates d'inscription aux études

Première soumission

27 avril 2026

Première soumission répondant aux critères de contrôle qualité

27 avril 2026

Première publication (Réel)

1 mai 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

12 mai 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

7 mai 2026

Dernière vérification

1 mai 2026

Plus d'information

Termes liés à cette étude

Mots clés

Termes MeSH pertinents supplémentaires

Autres numéros d'identification d'étude

  • FU_MGBeydagi_PFAS_B_2026/05

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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