Whole-Body Vibration in Patients With Patellofemoral Pain Syndrome

January 25, 2026 updated by: Hakan Alkan, Pamukkale University

Efficacy of Whole-Body Vibration in Patients With Patellofemoral Pain Syndrome: A Prospective, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Patellofemoral Pain Syndrome (PFPS), or anterior knee pain, is one of the most common disorders affecting the lower extremities.

Currently, there is no established "gold standard" treatment for PFPS. However, various interventions-including strengthening of the hip and knee muscles (e.g., hip abductors, external rotators, and knee extensors), taping, bracing, foot orthoses, manual therapy, acupuncture, blood flow restriction training, and conventional physical agents (e.g., ultrasound, cryotherapy, neuromuscular electrical stimulation, laser therapy, electromyographic biofeedback, etc.)-have been reported to provide meaningful clinical benefits. Strengthening of the hip and knee muscles alone has been shown to improve both pain and function in the short, medium, and long term. In recent high-quality studies, hip and knee muscle strengthening has been recognized as an effective "classical" treatment approach for PFPS. Regarding the mechanism of pain relief, previous research suggests that strengthening these muscles may alleviate pain by stabilizing patellar motion and/or reducing pressure on the patellofemoral joint.

Similar to traditional resistance training, whole-body vibration (WBV) training is an alternative method for muscle strengthening. WBV platforms can generate vertical vibrations that stimulate tonic vibration reflexes through muscle spindles, thereby activating homonymous alpha motor neurons and inducing reflex muscle contractions. As a result, increased motor unit recruitment enhances the excitability of muscle spindles, leading to improved muscle strength. Additionally, WBV training can improve muscle balance, strength, and function. Therefore, combining WBV with hip and knee strengthening exercises may represent a more effective treatment strategy for PFPS. The aim of this study is to evaluate whether the combination of WBV and hip-knee muscle strengthening is more effective in reducing pain and improving function than hip-knee strengthening alone.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Patellofemoral Pain Syndrome (PFPS), or anterior knee pain, is one of the most common disorders affecting the lower extremities.

Currently, there is no established "gold standard" treatment for PFPS. However, various interventions-including strengthening of the hip and knee muscles (e.g., hip abductors, external rotators, and knee extensors), taping, bracing, foot orthoses, manual therapy, acupuncture, blood flow restriction training, and conventional physical agents (e.g., ultrasound, cryotherapy, neuromuscular electrical stimulation, laser therapy, electromyographic biofeedback, etc.)-have been reported to provide meaningful clinical benefits. Strengthening of the hip and knee muscles alone has been shown to improve both pain and function in the short, medium, and long term. In recent high-quality studies, hip and knee muscle strengthening has been recognized as an effective "classical" treatment approach for PFPS. Regarding the mechanism of pain relief, previous research suggests that strengthening these muscles may alleviate pain by stabilizing patellar motion and/or reducing pressure on the patellofemoral joint.

Similar to traditional resistance training, whole-body vibration (WBV) training is an alternative method for muscle strengthening. WBV platforms can generate vertical vibrations that stimulate tonic vibration reflexes through muscle spindles, thereby activating homonymous alpha motor neurons and inducing reflex muscle contractions. As a result, increased motor unit recruitment enhances the excitability of muscle spindles, leading to improved muscle strength. Additionally, WBV training can improve muscle balance, strength, and function. Therefore, combining WBV with hip and knee strengthening exercises may represent a more effective treatment strategy for PFPS. The aim of this study is to evaluate whether the combination of WBV and hip-knee muscle strengthening is more effective in reducing pain and improving function than hip-knee strengthening alone.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
    • Pamukkale
      • Denizli, Pamukkale, Turkey (Türkiye), 20160
        • Pamukkale University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Aged between 18 and 40 years,
  • Diagnosed with unilateral Patellofemoral Pain Syndrome (PFPS),
  • Reporting anterior knee pain or pain behind the patella in at least two of the following activities:

ascending stairs, jumping, running, squatting, kneeling, prolonged sitting,

- Positive results in at least two of the following clinical tests: Eccentric step-down test, Patellar border tenderness test, Patellar grind (Clarke's) or apprehension test,

  • Ability to understand the procedures, potential benefits, and possible adverse effects,
  • Willingness to participate in the treatment program.

Exclusion Criteria:

  • Severe injury or pathological changes in knee structures (e.g., ligaments, menisci, patellar tendons, iliotibial bands, joint capsules, or plicae),
  • History of significant trauma or surgery involving the knee or lower extremity,
  • History of patellar dislocation or subluxation,
  • Diagnosis of Osgood-Schlatter disease or Sinding-Larsen-Johansson syndrome,
  • Joint effusion in the knee, or presence of redness, swelling, or increased warmth on physical examination,
  • Serious systemic conditions, including cardiovascular diseases, tumors, gallstones or kidney stones, severe disc or spinal lesions, pacemaker implantation, epilepsy, recent fractures or surgeries, or acute arthritis,
  • Pregnancy.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Experimental
Whole body vibration group, 3 days a week, 30 minutes a day for 8 weeks
Device: Whole body vibration
In this group, prior to the patient stepping onto the platform, the practitioner will turn off the vibration motor of the device and activate an external motor (which is not in contact with the WBV device, has no effective vibration capability, and only produces sound), installed by our team. Since the visual display of the device remains active, patients will not be aware that the actual vibration function is disabled, thereby preventing any bias related to device inactivity.
Sham Comparator: Sham group
Sham-whole body vibration, 3 days a week, 30 minutes a day for 8 weeks
Device: Sham Whole Body Vibration
In this group, prior to the patient stepping onto the platform, the practitioner will turn off the vibration motor of the device and activate an external motor (which is not in contact with the WBV device, has no effective vibration capability, and only produces sound), installed by our team. Since the visual display of the device remains active, patients will not be aware that the actual vibration function is disabled, thereby preventing any bias related to device inactivity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
VAS
Time Frame: Change from baseline VAS at the 8th week after the treatment
Pain is the most characteristic symptom in Patellofemoral Pain Syndrome (PFPS). After recording the duration of pain (in months) for each patient, pain intensity was assessed using the Visual Analog Scale (VAS), which is a 10-centimeter (cm) line anchored by 0 (no pain) and 10 (unbearable pain). Patients were asked to rate their pain at rest, during stair ascent/descent, squatting, prolonged sitting, and walking. Crossley et al. have reported that the VAS is a valid, reliable, and responsive tool for assessing pain in individuals with PFPS
Change from baseline VAS at the 8th week after the treatment

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Anterior Knee Pain Scale
Time Frame: Change from baseline AKPS score at the 8th week after the treatment
Subjective symptoms and functional limitations of patients with Patellofemoral Pain Syndrome (PFPS) were evaluated using the Kujala Patellofemoral Scoring System. This scoring system was developed by Kujala et al. in 1993, and it allows for functional assessment of knee pathologies related to the patellofemoral structure. The Kujala Patellofemoral Pain Score consists of 13 subcategories evaluating limping, weight bearing, walking, stair activities, squatting, jumping, prolonged sitting with knees flexed at 90°, running, pain, swelling, abnormal painful patellar movement, thigh atrophy, and loss of flexion. The total score ranges from 0 to 100 points, with 100 indicating the best functional status.
Change from baseline AKPS score at the 8th week after the treatment
Short Form - 36
Time Frame: Change from baseline SF-36 score at the 8th week after the treatment

The quality of life of all patients will be assessed using the Short Form-36 Health Survey (SF-36). This instrument consists of 36 items and measures eight health domains:

Physical functioning (10 items), Social functioning (2 items), Role limitations due to physical problems (4 items), Role limitations due to emotional problems (3 items), Mental health (5 items), Energy/vitality (4 items), Bodily pain (2 items), and General health perception (5 items)
Change from baseline SF-36 score at the 8th week after the treatment
Muscle Mass Assessment via Ultrasound
Time Frame: Change from baseline muscle mass assessment at the 8th week after the treatment

Muscle mass measurements of the vastus medialis and gluteus medius muscles will be performed using ultrasound (Clarius™ by Clarius Mobile Health) both before and after treatment.

For the vastus medialis, the patient will be positioned supine with the knee in approximately 30 degrees of flexion. The ultrasound probe will be placed on the medial quadriceps region, between the medial border of the patella and the medial femoral condyle. The probe will be angled at approximately 45° to the long axis of the femur, oriented parallel to the muscle fibers.

For the gluteus medius, the patient will be positioned in side-lying, with the painful side facing upward. The probe will be placed at the lower half of the distance between a line connecting the anterior superior iliac spine (ASIS) and the posterior superior iliac spine (PSIS) and the greater trochanter.

Measurements will be performed by the same evaluator at baseline and at the 8th week following treatment.
Change from baseline muscle mass assessment at the 8th week after the treatment
Change in peak torque at 60°/s (Nm) of the knee muscles measured by isokinetic dynamometer
Time Frame: Change from baseline to Week 8 after treatment
Isokinetic assessment of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position with stabilization of the trunk and lower limbs. Peak Torque (PT, measured in Newton-meters, Nm) represents the maximum torque generated during knee flexion and extension at an angular velocity of 60°/s. Participants will perform four maximal repetitions following three familiarization trials. The change in PT from baseline to week 8 will be used to assess improvement in knee muscle endurance at higher movement speeds.
Change from baseline to Week 8 after treatment
Change in peak torque at 240°/s (Nm) of the knee muscles measured by isokinetic dynamometer
Time Frame: Change from baseline to Week 8 after treatment

Isokinetic assessment of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position with stabilization of the trunk and lower limbs.

Peak Torque (PT, measured in Newton-meters, Nm) represents the maximum torque generated during knee flexion and extension at an angular velocity of 240°/s. Participants will perform ten maximal repetitions following three familiarization trials.

The change in PT from baseline to week 8 will be used to assess improvement in knee muscle endurance at higher movement speeds.
Change from baseline to Week 8 after treatment
Assessment of the hamstring/quadriceps ratio at 60°/s with an isokinetic dynamometer
Time Frame: Change from baseline VAS at the 8th week after the treatment

The H/Q ratio will be calculated using the peak torque values obtained from the isokinetic tests at 60°/s.

Specifically, it is determined by dividing the hamstring peak torque by the quadriceps peak torque measured during the same test session.

The H/Q ratio at this slower speed reflects the strength balance between the knee flexors and extensors under controlled movement conditions.

A balanced ratio is crucial for joint stability and injury prevention, particularly in patients with knee pain or dysfunction.

Testing will be conducted using the IsoMed 2000, with the patient's position and stabilization identical to other isokinetic assessments.
Change from baseline VAS at the 8th week after the treatment
Assessment of the hamstring/quadriceps ratio at 240°/s with an isokinetic dynamometer
Time Frame: Change from baseline to week 8 after treatment

The H/Q ratio will also be calculated at 240°/s, based on the peak torque values obtained from the high-velocity isokinetic test.

It is computed by dividing the hamstring peak torque by the quadriceps peak torque at this higher angular velocity.

The H/Q ratio at 240°/s assesses the dynamic balance and neuromuscular coordination between flexor and extensor muscle groups during rapid movements.

Maintaining an appropriate H/Q ratio at faster speeds is considered an important indicator of functional knee stability and injury resilience.

All procedures (positioning, stabilization, familiarization, and repetitions) will be performed identically to the other isokinetic test conditions, using the IsoMed 2000 system.
Change from baseline to week 8 after treatment
Change in Total Work (J) of the Knee Muscles at 60°/s With an Isokinetic Dynamometer
Time Frame: Change from baseline to Week 8 after treatment

Isokinetic assessments of the symptomatic (painful) knee will be performed using the IsoMed 2000 Isokinetic System. Participants will be seated in an upright position, with the chest, waist, and lower limbs secured to ensure proper body stabilization and minimize compensatory movements.

To obtain reliable data on muscle performance, testing at an angular velocity of 60°/s will include four consecutive maximal concentric repetitions of knee flexion and extension. Prior to the test, participants will perform three familiarization repetitions at the same velocity to become accustomed to the movement and the device.

Total Work (TW), measured in Joules (J), represents the total amount of work performed by the knee flexor and extensor muscles across all repetitions at 60°/s.

This parameter reflects overall muscular endurance and energy output of the quadriceps and hamstrings during slower, controlled movements.
Change from baseline to Week 8 after treatment
Change in Total Work (J) of the Knee Muscles at 240°/s With an Isokinetic Dynamometer
Time Frame: Change from baseline to Week 8 after treatment

Isokinetic assessments of the symptomatic (painful) knee will be conducted using the IsoMed 2000 Isokinetic System. Participants will be positioned in an upright seated position, and the chest, waist, and lower limbs will be secured with straps to ensure body stabilization during testing.

For this evaluation, an angular velocity of 240°/s will be used, and patients will perform ten consecutive maximal concentric repetitions of knee flexion and extension. Before the test, three familiarization repetitions at the same angular velocity will be completed to ensure accurate and consistent performance.

Total Work (TW), expressed in Joules (J), will represent the total energy output of the knee flexor and extensor muscles during all repetitions at 240°/s.

This measurement provides information on muscular endurance, power, and performance efficiency of the knee muscles under high-velocity dynamic conditions.
Change from baseline to Week 8 after treatment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Pamukkale University

Investigators

  • Study Director: Hakan Alkan, Prof Dr, Pamukkale University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 15, 2026

Primary Completion (Estimated)

February 15, 2026

Study Completion (Estimated)

August 1, 2026

Study Registration Dates

First Submitted

August 9, 2025

First Submitted That Met QC Criteria

January 25, 2026

First Posted (Actual)

February 2, 2026

Study Record Updates

Last Update Posted (Actual)

February 2, 2026

Last Update Submitted That Met QC Criteria

January 25, 2026

Last Verified

August 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PamukkaleU.ftr-HAlkan-001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Patellofemoral Pain, PFP

Clinical Trials on Whole body vibration

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Denmark

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe