Comparative Effects Of Clamshell And Short Arc Quadriceps Exercises In Patellofemoral Pain

NCT07646431 | Completed DMC

• 1 other identifier: GIU/REC/26-40
• Study Type: interventional
• Target: 34
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Patellofemoral Pain Syndrome

Keywords

Patellofemoral Pain Syndrome; Clamshell Exercises; Short Arc Quadriceps; Knee Pain; Hip Strengthening; Quadriceps Strengthening; Physical Therapy

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline and 12 weeks post-intervention

Secondary Outcomes (2)

• Change in Knee Function

  Baseline and 12 weeks post-intervention

• Change in Quality of Life

  Baseline and 12 weeks post-intervention

Study Arms (2)

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 \[X weeks\], \[frequency per week\].

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 \[X weeks\], \[frequency per week\].

Procedure: Short Arc Quadriceps Exercise

Interventions

Clamshell Exercise PROCEDURE

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.

Also known as: Sude-lying Hip Abduction, Shell Exercise

Clamshell Exercise Group

Short Arc Quadriceps Exercise PROCEDURE

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.

Also known as: SAQ Exercise, Terminal Knee Extension, Short Range Quadricepa

Short Arc Quadriceps Exercise Group

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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.

Sponsors & Collaborators

• Green International University: lead

Study Sites (1)

Tehsil Headquarter Hospital, Bahlwal

Sargodha, Punjab Province, 40100, Pakistan

Location

MeSH Terms

Conditions

Patellofemoral Pain Syndrome

Condition Hierarchy (Ancestors)

Joint Diseases; Musculoskeletal Diseases

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Model Details: 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.

Study Record Dates

• First Submitted: June 9, 2026
• First Posted: June 12, 2026
• Study Start: November 2, 2025
• Primary Completion: April 29, 2026
• Study Completion: May 5, 2026
• Last Updated: June 12, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR
• Time Frame: It will be available after the completion of the study.
• Access Criteria: Data requests should be sent to the corresponding author. Access will be granted to qualified researchers for approved research proposals. Data will be de-identified before sharing.

Locations

PA (1)