Patellar Tendinopathy / Jumpers KneeppnsNCT07237867
Frequency-Dependent Effects of Percutaneous Femoral Nerve Stimulation on Quadriceps Strength in Athletes With Patellar Tendinopathy
A study testing Electrical stimulation in people with Patellar Tendinopathy / Jumpers Knee, run by Hospital Clinic of Barcelona at 1 site in Spain.
Trial summary
This study investigates the immediate effects of different peripheral electrical nerve stimulation protocols applied to the femoral nerve on quadriceps strength in athletes with patellar tendinopathy. Read more about this study
- Who is it for?
- Ages 18 to 40 years, men only
- Conditions the study is for
- Patellar Tendinopathy / Jumpers Knee
- What is being tested?
- Electrical stimulation
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 1 siteSpain
- Study dates
- 20 Sep 2025to 15 Dec 2025
- 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 40 years
- Men only
- No healthy volunteers
- Adult
Who may be able to join
- Adults aged 18 to 40 years.
- Recreational or competitive athletes with clinically diagnosed patellar tendinopathy for at least 3 months.
- Ultrasound-confirmed patellar tendinopathy, including hypoechoic areas, tendon thickening, or neovascularization consistent with clinical diagnosis.
- Presence of pain during tendon-loading activities (e.g., jumping, running, squatting).
- Ability to perform maximal voluntary isometric contractions of the quadriceps.
- Ability to comply with all study procedures and attend all experimental sessions.
- Written informed consent obtained prior to participation.
Who cannot join
- Previous knee surgery or traumatic knee injury within the past 12 months.
- Complete or partial patellar tendon rupture.
- Neurological disorders affecting lower limb strength or motor control.
- Contraindications to electrical stimulation, including implanted electrical devices (e.g., pacemaker).
- Current lower-limb radiculopathy or neuropathy.
- Skin infections, open wounds, or dermatological conditions at the stimulation site.
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- Use of analgesics, anti-inflammatories, or corticosteroid injections within the past 48 hours.
- Participation in another interventional study in the previous 30 days.
- Pregnancy or suspected pregnancy.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Spain1 site, 1 recruiting
- Recruiting
Blanquerna University
Barcelona, Barcelona, 08020
Francesco Sartori, Phd, 663583945, sartorifrancesco99@gmail.com
About this study
Official title: Frequency-Dependent Effects of Percutaneous Femoral Nerve Stimulation on Strength in Athletes With Patellar Tendinopathy: a Randomized Controlled Trial
This study investigates the immediate effects of different peripheral electrical nerve stimulation protocols applied to the femoral nerve on quadriceps strength in athletes with patellar tendinopathy. Patellar tendinopathy is a common overuse injury that often reduces quadriceps activation and limits sports performance. Peripheral percutaneous nerve stimulation (PPNS) and transcutaneous electrical nerve stimulation (TENS) are frequently used in rehabilitation, but their frequency-dependent effects on muscle strength are not well established.
In this randomized crossover trial, each participant receives three stimulation protocols in separate sessions: high-frequency PPNS (100 Hz), low-frequency PPNS (2 Hz), and conventional TENS. All stimulation is delivered at the maximal tolerated motor threshold and, for PPNS conditions, under ultrasound guidance. Quadriceps maximal isometric strength is evaluated using an isometric force sensor before and after each intervention.
Read more
The primary objective is to compare the acute changes in maximal voluntary contraction (MVC) following each stimulation protocol. The study aims to clarify whether different stimulation frequencies can enhance, reduce, or have no effect on quadriceps strength in this athletic population.
By identifying frequency-specific neuromodulatory responses, this study may help clinicians and sports practitioners select the most appropriate stimulation parameters to optimize rehabilitation and performance in individuals with patellar tendinopathy.
- Conditions
- Patellar Tendinopathy / Jumpers Knee
- Being tested
- Electrical stimulation
- Keywords
- Peripheral Percutaneous Nerve Stimulation, Transcutaneous Electrical Nerve Stimulation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Electrical stimulationDevice
Also called Ultrasound-guided electrical stimulation
All electrical stimulation procedures are performed under real-time ultrasound guidance to accurately locate the femoral nerve and ensure safe and consistent electrode placement. For the percutaneous interventions (PPNS), a sterile needle electrode is inserted adjacent to the femoral nerve and stimulation is delivered at either high frequency (100 Hz) or low frequency (2 Hz), depending on the study arm. For the transcutaneous intervention (TENS), surface electrodes are positioned over the femoral nerve region using ultrasound guidance to confirm anatomical landmarks and optimize current delivery. In all conditions, stimulation is applied at the maximal tolerated motor threshold to elicit visible quadriceps activation.
| Study group | Role | What they receive |
|---|---|---|
| High-Frequency PPNS (100 Hz) | Experimental | Participants receive peripheral percutaneous nerve stimulation (PPNS) applied to the femoral nerve at 100 Hz. Receives: Device: Electrical stimulation |
| Low-Frequency PPNS (2 Hz) | Experimental | Participants receive peripheral percutaneous nerve stimulation (PPNS) applied to the femoral nerve at 2 Hz. Receives: Device: Electrical stimulation |
| Transcutaneous Electrical Nerve Stimulation (TENS) | Active comparator | Participants receive conventional transcutaneous electrical nerve stimulation (TENS) applied over the femoral nerve region using surface electrodes. Intensity is set at the maximal tolerated motor threshold to elicit visible quadriceps activation. The stimulation frequency and parameters are consistent with standard clinical practice for motor-level TENS. Receives: Device: Electrical stimulation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Quadriceps Maximal Isometric Voluntary Contraction (MVC)
Quadriceps maximal isometric voluntary contraction (MVC) is measured using a calibrated isometric force sensor with the participant seated and the knee positioned at 60° of flexion. MVC is recorded as the peak force output during a standardized 5-second maximal contraction. The primary endpoint is the change in MVC from pre-intervention to immediately post-intervention across the three stimulation conditions (high-frequency PPNS, low-frequency PPNS, and TENS). Higher values indicate greater quadriceps force production.
Measured: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Secondary outcomes (3)
Change in Quadriceps Rate of Force Development (RFD 0-250 ms)
Quadriceps rate of force development (RFD) in the early phase of contraction (0-250 ms) is calculated from the force-time curve obtained during maximal isometric voluntary contractions using a calibrated isometric force sensor. RFD 0-250 ms reflects the participant's ability to rapidly generate force and is derived as the slope of the force increase within the first 250 milliseconds. The outcome measure is the change in RFD between baseline and the post-intervention time points across the three stimulation conditions (high-frequency PPNS, low-frequency PPNS, and TENS).
Measured: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Change in Quadriceps Impulse (0-250 ms)
Quadriceps impulse (0-250 ms) is calculated as the integrated area under the force-time curve during the first 250 milliseconds of a maximal isometric voluntary contraction, recorded using a calibrated isometric force sensor. This metric reflects the combined ability to rapidly generate and sustain force during the early phase of contraction. The outcome measure is the change in impulse between baseline and post-intervention assessments across the three stimulation conditions (high-frequency PPNS, low-frequency PPNS, and TENS).
Measured: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Incidence of Adverse Events Assessed Through Post-Intervention Questionnaires
Adverse events related to the stimulation procedures are assessed using a standardized post-intervention questionnaire completed immediately after each stimulation session. Participants are asked to report the presence and severity of any undesirable effects, including discomfort, pain, bleeding, bruising, transient paresthesia, dizziness, or any unexpected symptoms. All adverse events are recorded, categorized by type and severity, and evaluated for their potential relationship to the intervention (high-frequency PPNS, low-frequency PPNS, or TENS). No serious adverse events are anticipated due to the low-risk nature of the procedures.
Measured: Immediately after each intervention session.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Nov 2025
- Study start20 Sep 2025
- Primary completion30 Nov 2025 (estimated)
- Study completion15 Dec 2025 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Patellar Tendinopathy / Jumpers KneeStudies of the same condition, open and under way.
- More trials run by Hospital Clinic of BarcelonaThe sponsor's other registered studies.
- 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
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 19 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Hospital Clinic of Barcelona
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Xavier Picañol Parraga, Hospital Clinic of Barcelona
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07237867
- Sponsor's protocol ID
- 2025-04-05
- Acronym
- ppns
- Status last verified
- Nov 2025
- First submitted
- 15 Nov 2025
- Last updated
- 5 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: No final decision has yet been made regarding the sharing of de-identified individual participant data (IPD) from this study. Data sharing may be considered after publication of the study results and pending compliance with ethical approvals, institutional policies, and participant confidentiality protections. Only fully de-identified datasets would be eligible for potential sharing. Access Criteria and How to Request IPD If data sharing is approved in the future, de-identified IPD will be made available to qualified researchers upon reasonable request. Interested investigators may contact the Principal Investigator with a methodologically sound proposal. Access will be granted only after review of the request and signature of a data use agreement.
Study at a glance
From the registry record, last updated by the sponsor on 5 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Frequency-Dependent Effects of Percutaneous Femoral Nerve Stimulation on Strength in Athletes With Patellar Tendinopathy: a Randomized Controlled Trial
- ClinicalTrials.gov ID
- NCT07237867
- Acronym / sponsor ID
- ppns / 2025-04-05
- Conditions
- Patellar Tendinopathy / Jumpers Knee
- Keywords
- Peripheral Percutaneous Nerve Stimulation, Transcutaneous Electrical Nerve Stimulation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 19 participants (estimated)
- Lead sponsor
- Hospital Clinic of BarcelonaUniversity, hospital or other
- Study start
- 20 Sep 2025 (actual)
- Primary completion
- 30 Nov 2025 (estimated)
- Study completion
- 15 Dec 2025 (estimated)
- First posted
- 20 Nov 2025 (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.
This study investigates the immediate effects of different peripheral electrical nerve stimulation protocols applied to the femoral nerve on quadriceps strength in athletes with patellar tendinopathy. Patellar tendinopathy is a common overuse injury that often reduces quadriceps activation and limits sports performance. Peripheral percutaneous nerve stimulation (PPNS) and transcutaneous electrical nerve stimulation (TENS) are frequently used in rehabilitation, but their frequency-dependent effects on muscle strength are not well established.
In this randomized crossover trial, each participant receives three stimulation protocols in separate sessions: high-frequency PPNS (100 Hz), low-frequency PPNS (2 Hz), and conventional TENS. All stimulation is delivered at the maximal tolerated motor threshold and, for PPNS conditions, under ultrasound guidance. Quadriceps maximal isometric strength is evaluated using an isometric force sensor before and after each intervention.
The primary objective is to compare the acute changes in maximal voluntary contraction (MVC) following each stimulation protocol. The study aims to clarify whether different stimulation frequencies can enhance, reduce, or have no effect on quadriceps strength in this athletic population.
By identifying frequency-specific neuromodulatory responses, this study may help clinicians and sports practitioners select the most appropriate stimulation parameters to optimize rehabilitation and performance in individuals with patellar tendinopathy.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| High-Frequency PPNS (100 Hz) | Experimental | Device: Electrical stimulationParticipants receive peripheral percutaneous nerve stimulation (PPNS) applied to the femoral nerve at 100 Hz. |
| Low-Frequency PPNS (2 Hz) | Experimental | Device: Electrical stimulationParticipants receive peripheral percutaneous nerve stimulation (PPNS) applied to the femoral nerve at 2 Hz. |
| Transcutaneous Electrical Nerve Stimulation (TENS) | Active comparator | Device: Electrical stimulationParticipants receive conventional transcutaneous electrical nerve stimulation (TENS) applied over the femoral nerve region using surface electrodes. Intensity is set at the maximal tolerated motor threshold to elicit visible quadriceps activation. The stimulation frequency and parameters are consistent with standard clinical practice for motor-level TENS. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- Male only
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Adults aged 18 to 40 years.
- Recreational or competitive athletes with clinically diagnosed patellar tendinopathy for at least 3 months.
- Ultrasound-confirmed patellar tendinopathy, including hypoechoic areas, tendon thickening, or neovascularization consistent with clinical diagnosis.
- Presence of pain during tendon-loading activities (e.g., jumping, running, squatting).
- Ability to perform maximal voluntary isometric contractions of the quadriceps.
Key exclusion criteria (9 listed)
- Previous knee surgery or traumatic knee injury within the past 12 months.
- Complete or partial patellar tendon rupture.
- Neurological disorders affecting lower limb strength or motor control.
- Contraindications to electrical stimulation, including implanted electrical devices (e.g., pacemaker).
- Current lower-limb radiculopathy or neuropathy.
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 |
|---|---|---|
| Electrical stimulationAlso: Ultrasound-guided electrical stimulationAll electrical stimulation procedures are performed under real-time ultrasound guidance to accurately locate the femoral nerve and ensure safe and consistent electrode placement. For the percutaneous interventions (PPNS), a sterile needle electrode is inserted adjacent to the femoral nerve and stimulation is delivered at either high frequency (100 Hz) or low frequency (2 Hz), depending on the study arm. For the transcutaneous intervention (TENS), surface electrodes are positioned over the femoral nerve region using ultrasound guidance to confirm anatomical landmarks and optimize current delivery. In all conditions, stimulation is applied at the maximal tolerated motor threshold to elicit visible quadriceps activation. | Device | High-Frequency PPNS (100 Hz), Low-Frequency PPNS (2 Hz), Transcutaneous Electrical Nerve Stimulation (TENS) |
Primary outcome
Change in Quadriceps Maximal Isometric Voluntary Contraction (MVC)
Time frame: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Quadriceps maximal isometric voluntary contraction (MVC) is measured using a calibrated isometric force sensor with the participant seated and the knee positioned at 60° of flexion. MVC is recorded as the peak force output during a standardized 5-second maximal contraction. The primary endpoint is the change in MVC from pre-intervention to immediately post-intervention across the three stimulation conditions (high-frequency PPNS, low-frequency PPNS, and TENS). Higher values indicate greater quadriceps force production.
3 secondary outcomes
Change in Quadriceps Rate of Force Development (RFD 0-250 ms)
Time frame: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Change in Quadriceps Impulse (0-250 ms)
Time frame: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.
Incidence of Adverse Events Assessed Through Post-Intervention Questionnaires
Time frame: Immediately after each intervention session.
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 5 Dec 2025.
- Individual participant dataSharing planned: Undecided. No final decision has yet been made regarding the sharing of de-identified individual participant data (IPD) from this study. Data sharing may be considered after publication of the study results and pending compliance with ethical approvals, institutional policies, and participant confidentiality protections. Only fully de-identified datasets would be eligible for potential sharing. Access Criteria and How to Request IPD If data sharing is approved in the future, de-identified IPD will be made available to qualified researchers upon reasonable request. Interested investigators may contact the Principal Investigator with a methodologically sound proposal. Access will be granted only after review of the request and signature of a data use agreement.
Related trials for Patellar Tendinopathy / Jumpers Knee
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Enrolling by invitation
Comparison of Ultrasound-guided Electrolysis Therapy vs. Sham Electrolysis in Patients With Patellar Tendinopathy: A Prospective Randomized Study Including MRI and Shear-wave Ultrasound Elastography Imaging
Patellar Tendinopathy / Jumpers Knee
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 Electrical stimulation in people with Patellar Tendinopathy / Jumpers Knee, run by Hospital Clinic of Barcelona at 1 site in Spain.
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 7 inclusion and 9 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 5 Dec 2025. 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 Spain. 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 Javier Picañol Parraga Picañol, Phd (+34655394127, xpicanol@ub.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Quadriceps Maximal Isometric Voluntary Contraction (MVC) (time frame: Baseline (pre-intervention), and at 2 minutes, 10 minutes, 15 minutes, and 30 minutes post-intervention.). 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 5 Dec 2025.