Effects of Isometric, Isotonic, and Eccentric VMO Exercises in Patellofemoral Pain Syndrome (VMO-PFPS)
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.
Visão geral do estudo
Status
Intervenção / Tratamento
Descrição detalhada
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.
Tipo de estudo
Inscrição (Estimado)
Estágio
- Não aplicável
Contactos e Locais
Contato de estudo
- Nome: Muharrem Gökhan Beydağı, PhD
- Número de telefone: +905323581105
- E-mail: mgbeydagi@firat.edu.tr
Locais de estudo
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MErkez
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Elâzığ, MErkez, Turquia (Türkiye), 23200
- Firat University
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Contato:
- Muharrem Beydağı, PhD
- Número de telefone: 05323581105
- E-mail: fztgokhan@hotmail.com
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Investigador principal:
- Muhammet Şahin Elbastı, PhD
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Critérios de participação
Critérios de elegibilidade
Idades elegíveis para estudo
- Adulto
Aceita Voluntários Saudáveis
Descrição
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
Plano de estudo
Como o estudo é projetado?
Detalhes do projeto
- Finalidade Principal: Tratamento
- Alocação: Randomizado
- Modelo Intervencional: Atribuição Paralela
- Mascaramento: Solteiro
Armas e Intervenções
Grupo de Participantes / Braço |
Intervenção / Tratamento |
|---|---|
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Experimental: 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.
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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.
Outros nomes:
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Experimental: 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.
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Participants will perform controlled concentric and eccentric contractions using ankle weights through a limited range of motion (0-30° knee extension).
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Experimental: 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.
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Participants will perform eccentric contractions against resistance during knee flexion, with assisted concentric return to the starting position.
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O que o estudo está medindo?
Medidas de resultados primários
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
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VMO Muscle Architecture (Ultrasound)
Prazo: Baseline and Week 8
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Muscle thickness, fascicle length, pennation angle, and physiological cross-sectional area of the vastus medialis oblique muscle will be assessed using ultrasound imaging.
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Baseline and Week 8
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Medidas de resultados secundários
Medida de resultado |
Descrição da medida |
Prazo |
|---|---|---|
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Pain Intensity (Visual Analog Scale, VAS)
Prazo: Baseline and Week 8
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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.
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Baseline and Week 8
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Functional Status (WOMAC Index)
Prazo: Baseline and Week 8
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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.
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Baseline and Week 8
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30-Second Sit-to-Stand Test
Prazo: Baseline and Week 8
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The number of repetitions completed in 30 seconds will be recorded to assess lower extremity functional strength.
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Baseline and Week 8
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Stair Ascent and Descent Test
Prazo: Baseline and Week 8
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Time required to ascend and descend a standardized 9-step staircase will be recorded in seconds.
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Baseline and Week 8
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Hip Muscle Architecture (Ultrasound)
Prazo: Baseline and Week 8
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Muscle architecture parameters of the hip muscles (adductors and tensor fascia lata) will be evaluated using ultrasound imaging.
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Baseline and Week 8
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Colaboradores e Investigadores
Patrocinador
Datas de registro do estudo
Datas Principais do Estudo
Início do estudo (Estimado)
Conclusão Primária (Estimado)
Conclusão do estudo (Estimado)
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Enviado pela primeira vez que atendeu aos critérios de CQ
Primeira postagem (Real)
Atualizações de registro de estudo
Última Atualização Postada (Real)
Última atualização enviada que atendeu aos critérios de controle de qualidade
Última verificação
Mais Informações
Termos relacionados a este estudo
Palavras-chave
Termos MeSH relevantes adicionais
Outros números de identificação do estudo
- FU_MGBeydagi_PFAS_B_2026/05
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