Patellofemoral Pain SyndromeCASCAPE-PFPSNCT07646431
Comparative Effects Of Clamshell And Short Arc Quadriceps Exercises In Patellofemoral Pain
A study testing Clamshell Exercise and Short Arc Quadriceps Exercise in people with Patellofemoral Pain Syndrome, run by Green International University at 1 site in Pakistan.
Trial summary
This is a research study to compare two different exercises for people who have patellofemoral pain syndrome. Patellofemoral pain syndrome means pain around or behind the kneecap, which is also called "runner's knee". People in this study will be divided into two groups by chance. Read more about this study
- Who is it for?
- Ages 18 to 40 years
- Conditions the study is for
- Patellofemoral Pain Syndrome
- What is being tested?
- Clamshell Exercise and Short Arc Quadriceps Exercise
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 34 participants
- Where
- 1 sitePakistan
- Study dates
- 2 Nov 2025to 5 May 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
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
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Patients diagnosed with Patellofemoral Pain Syndrome Age between 18-40 years. Male and female participants Presence of anterior knee pain for at least 4 weeks Pain aggravated by activities such as stair climbing, squatting, running, or prolonged sitting Willingness to participate and provide informed consent
Who cannot join
- History of knee surgery or fracture around the knee joint Ligament injuries (e.g., ACL, PCL tears) or meniscal injuries Presence of other knee conditions (e.g., osteoarthritis, patellar dislocation). Neurological disorders affecting lower limb sensations and gait Current participation in any other physiotherapy or rehabilitation program Systemic inflammatory conditions (e.g., rheumatoid arthritis). Cognitive impairment or inability to follow instructions/attend sessions. Use of long-term steroids, strong analgesics, or anti-inflammatory medications.
Trial locations and contacts
1 site in 1 country.
Pakistan1 site
Tehsil Headquarter Hospital, Bahlwal
Sargodha, Punjab Province, 40100
About this study
Official title: Comparative Effects Of Clam Shell Exercises And Short Arc Quadriceps Strengthening Exercises On Pain, Functional Disability And Quality Of Life In Patellofemoral Pain Syndrome
This is a research study to compare two different exercises for people who have patellofemoral pain syndrome. Patellofemoral pain syndrome means pain around or behind the kneecap, which is also called "runner's knee".
People in this study will be divided into two groups by chance. One group will do clamshell exercises. This exercise strengthens hip muscles. The other group will do short arc quadriceps exercises. This exercise strengthens thigh muscles near the knee. Both groups will do their exercises for the same number of weeks.
Read more
The main goal of this study is to see which exercise reduces knee pain better and helps patients do daily activities more easily. We will also check if quality of life improves after doing these exercises.
Pain level, knee function, and quality of life will be checked before starting exercises and again after finishing the exercise program.
The results may help doctors and physical therapists choose the best exercise for patients with kneecap pain.
Read the detailed description
This randomized parallel-group clinical trial will compare the effectiveness of clamshell exercises versus short arc quadriceps strengthening exercises in patients diagnosed with patellofemoral pain syndrome.
Study Design: Participants meeting inclusion criteria for patellofemoral pain syndrome will be randomly allocated into two intervention groups.
Group 1 - Clamshell Exercise Group: Participants will perform clamshell exercises targeting hip abductors and external rotators, specifically gluteus medius and gluteus maximus muscles.
Group 2 - Short Arc Quadriceps Group: Participants will perform short arc quadriceps strengthening exercises focusing on quadriceps femoris muscle, with emphasis on vastus medialis obliquus activation.
Intervention Duration: Both groups will follow supervised exercise protocols for [X weeks]. Frequency and repetitions will be as per standard protocol.
Outcome Measures:
Primary: Pain intensity using Visual Analog Scale, Functional disability using Kujala Anterior Knee Pain Scale, Quality of Life using SF-36 questionnaire.
Assessments will be conducted at baseline, mid-intervention, and post-intervention to compare changes between the two exercise groups.
Hypothesis: Clamshell exercises targeting hip muscles may show superior effects on pain and function compared to short arc quadriceps exercises in PFPS patients.
- Conditions
- Patellofemoral Pain Syndrome
- Being tested
- Clamshell Exercise, Short Arc Quadriceps Exercise
- Keywords
- Patellofemoral Pain Syndrome, Clamshell Exercises, Short Arc Quadriceps, Knee Pain, Hip Strengthening, Quadriceps Strengthening, Physical Therapy
- 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.
Clamshell ExerciseProcedure or surgery
Also called Sude-lying Hip Abduction, Shell Exercise
A hip strengthening exercise performed in side-lying position with hips and knees flexed. Patient opens top knee like a clamshell while keeping feet together to strengthen gluteus medius and external rotators.
Short Arc Quadriceps ExerciseProcedure or surgery
Also called SAQ Exercise, Terminal Knee Extension, Short Range Quadricepa
A knee strengthening exercise performed in short range of motion from 30 degrees to full extension. Patient extends knee against resistance while quadriceps muscle is activated, focusing on vastus medialis obliquus.
| Study group | Role | What they receive |
|---|---|---|
| Clamshell Exercise Group | Experimental | Participants in this group will perform clamshell exercises targeting hip abductors and external rotators. Exercise includes side-lying hip abduction with knees bent at 45 degrees, focusing on gluteus medius and gluteus maximus strengthening. Sessions will be supervised by physical therapist for [X weeks], [frequency per week]. Receives: Procedure: Clamshell Exercise |
| Short Arc Quadriceps Exercise Group | Experimental | Participants in this group will perform short arc quadriceps strengthening exercises targeting quadriceps femoris muscle with emphasis on vastus medialis obliquus activation. Exercise performed from 30 to 0 degrees knee extension in short arc range. Sessions will be supervised by physical therapist for [X weeks], [frequency per week]. Receives: Procedure: Short Arc Quadriceps Exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Pain Intensity
Pain intensity will be assessed using Visual Analog Scale (VAS). VAS is a 10cm horizontal line where 0 = no pain and 10 = worst pain imaginable. Patients mark their current knee pain level. Change in VAS score will be measured from baseline to post-intervention after completion of exercise program.
Measured: Baseline and 12 weeks post-intervention
Secondary outcomes (2)
Change in Knee Function
Knee function will be assessed using Kujala Anterior Knee Pain Scale (AKPS). AKPS is a 13-item questionnaire specific for patellofemoral pain syndrome. Total score ranges from 0 to 100, where 100 = no limitation and 0 = maximum limitation. Change in AKPS score will be measured from baseline to post-intervention.
Measured: Baseline and 12 weeks post-intervention
Change in Quality of Life
Quality of life will be assessed using Short Form-36 Health Survey (SF-36). SF-36 includes 8 domains: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, mental health. Scores range from 0 to 100 for each domain. Change in SF-36 scores will be measured from baseline to post-intervention.
Measured: Baseline and 12 weeks post-intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Jun 2026
- Study start2 Nov 2025
- Primary completion29 Apr 2026
- Study completion5 May 2026
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
- Randomized parallel-group study. Patients with patellofemoral pain syndrome will be assigned to Group 1: Clamshell exercise or Group 2: Short arc quadriceps exercise. Both groups receive supervised exercise for same duration.
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 34 participants (actual)
Sponsor and investigators
- Lead sponsor
- Green International University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Laraib Fatima, Green International University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07646431
- Sponsor's protocol ID
- GIU/REC/26-40
- Acronym
- CASCAPE-PFPS
- Status last verified
- Jun 2026
- First submitted
- 9 Jun 2026
- Last updated
- 12 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Only IPD used in the results publication willbe shared.
Study at a glance
From the registry record, last updated by the sponsor on 12 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparative Effects Of Clam Shell Exercises And Short Arc Quadriceps Strengthening Exercises On Pain, Functional Disability And Quality Of Life In Patellofemoral Pain Syndrome
- ClinicalTrials.gov ID
- NCT07646431
- Acronym / sponsor ID
- CASCAPE-PFPS / GIU/REC/26-40
- Conditions
- Patellofemoral Pain Syndrome
- Keywords
- Patellofemoral Pain Syndrome, Clamshell Exercises, Short Arc Quadriceps, Knee Pain, Hip Strengthening, Quadriceps Strengthening, Physical Therapy
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 34 participants (actual)
- Lead sponsor
- Green International UniversityUniversity, hospital or other
- Study start
- 2 Nov 2025 (actual)
- Primary completion
- 29 Apr 2026 (actual)
- Study completion
- 5 May 2026 (actual)
- First posted
- 12 Jun 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.
This is a research study to compare two different exercises for people who have patellofemoral pain syndrome. Patellofemoral pain syndrome means pain around or behind the kneecap, which is also called "runner's knee".
People in this study will be divided into two groups by chance. One group will do clamshell exercises. This exercise strengthens hip muscles. The other group will do short arc quadriceps exercises. This exercise strengthens thigh muscles near the knee. Both groups will do their exercises for the same number of weeks.
The main goal of this study is to see which exercise reduces knee pain better and helps patients do daily activities more easily. We will also check if quality of life improves after doing these exercises.
Pain level, knee function, and quality of life will be checked before starting exercises and again after finishing the exercise program.
The results may help doctors and physical therapists choose the best exercise for patients with kneecap pain.
Detailed description
This randomized parallel-group clinical trial will compare the effectiveness of clamshell exercises versus short arc quadriceps strengthening exercises in patients diagnosed with patellofemoral pain syndrome.
Study Design: Participants meeting inclusion criteria for patellofemoral pain syndrome will be randomly allocated into two intervention groups.
Group 1 - Clamshell Exercise Group: Participants will perform clamshell exercises targeting hip abductors and external rotators, specifically gluteus medius and gluteus maximus muscles.
Group 2 - Short Arc Quadriceps Group: Participants will perform short arc quadriceps strengthening exercises focusing on quadriceps femoris muscle, with emphasis on vastus medialis obliquus activation.
Intervention Duration: Both groups will follow supervised exercise protocols for [X weeks]. Frequency and repetitions will be as per standard protocol.
Outcome Measures:
Primary: Pain intensity using Visual Analog Scale, Functional disability using Kujala Anterior Knee Pain Scale, Quality of Life using SF-36 questionnaire.
Assessments will be conducted at baseline, mid-intervention, and post-intervention to compare changes between the two exercise groups.
Hypothesis: Clamshell exercises targeting hip muscles may show superior effects on pain and function compared to short arc quadriceps exercises in PFPS patients.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized parallel-group study. Patients with patellofemoral pain syndrome will be assigned to Group 1: Clamshell exercise or Group 2: Short arc quadriceps exercise. Both groups receive supervised exercise for same duration.
| Arm | Type | Receives |
|---|---|---|
| Clamshell Exercise Group | Experimental | Procedure: Clamshell ExerciseParticipants in this group will perform clamshell exercises targeting hip abductors and external rotators. Exercise includes side-lying hip abduction with knees bent at 45 degrees, focusing on gluteus medius and gluteus maximus strengthening. Sessions will be supervised by physical therapist for [X weeks], [frequency per week]. |
| Short Arc Quadriceps Exercise Group | Experimental | Procedure: Short Arc Quadriceps ExerciseParticipants in this group will perform short arc quadriceps strengthening exercises targeting quadriceps femoris muscle with emphasis on vastus medialis obliquus activation. Exercise performed from 30 to 0 degrees knee extension in short arc range. Sessions will be supervised by physical therapist for [X weeks], [frequency per week]. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- Patients diagnosed with Patellofemoral Pain Syndrome Age between 18-40 years. Male and female participants Presence of anterior knee pain for at least 4 weeks Pain aggravated by activities such as stair climbing, squatting, running, or prolonged sitting Willingness to participate and provide informed consent
Key exclusion criteria (1 listed)
- History of knee surgery or fracture around the knee joint Ligament injuries (e.g., ACL, PCL tears) or meniscal injuries Presence of other knee conditions (e.g., osteoarthritis, patellar dislocation). Neurological disorders affecting lower limb sensations and gait Current participation in any other physiotherapy or rehabilitation program Systemic inflammatory conditions (e.g., rheumatoid arthritis). Cognitive impairment or inability to follow instructions/attend sessions. Use of long-term steroids, strong analgesics, or anti-inflammatory medications.
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 |
|---|---|---|
| Clamshell ExerciseAlso: Sude-lying Hip Abduction, Shell ExerciseA hip strengthening exercise performed in side-lying position with hips and knees flexed. Patient opens top knee like a clamshell while keeping feet together to strengthen gluteus medius and external rotators. | Procedure or surgery | Clamshell Exercise Group |
| Short Arc Quadriceps ExerciseAlso: SAQ Exercise, Terminal Knee Extension, Short Range QuadricepaA knee strengthening exercise performed in short range of motion from 30 degrees to full extension. Patient extends knee against resistance while quadriceps muscle is activated, focusing on vastus medialis obliquus. | Procedure or surgery | Short Arc Quadriceps Exercise Group |
Primary outcome
Change in Pain Intensity
Time frame: Baseline and 12 weeks post-intervention
Pain intensity will be assessed using Visual Analog Scale (VAS). VAS is a 10cm horizontal line where 0 = no pain and 10 = worst pain imaginable. Patients mark their current knee pain level. Change in VAS score will be measured from baseline to post-intervention after completion of exercise program.
2 secondary outcomes
Change in Knee Function
Time frame: Baseline and 12 weeks post-intervention
Change in Quality of Life
Time frame: Baseline and 12 weeks post-intervention
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Jun 2026.
- Individual participant dataSharing planned: Yes. Only IPD used in the results publication willbe shared.
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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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Clamshell Exercise and Short Arc Quadriceps Exercise in people with Patellofemoral Pain Syndrome, run by Green International University at 1 site in Pakistan.
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 1 inclusion and 1 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: finished, as of the sponsor's last update on 12 Jun 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 Pakistan. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Pain Intensity (time frame: Baseline and 12 weeks 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 12 Jun 2026.