Effects of Attentional Focus Strategies During Isokinetic Quadriceps Training on Strength and Functional Performance in Individuals With Patellofemoral Pain Syndrome.

Patellofemoral pain syndrome (PFPS) is a multifactorial musculoskeletal condition that is common particularly among young and physically active individuals, negatively affecting activities of daily living and physical performance. Although exercise therapy is considered the gold standard in the management of PFPS, there is limited evidence regarding the effectiveness of motor learning strategies applied during exercise. This study aims to shed light on how motor learning approaches can be optimized in clinical rehabilitation by comparing the effects of internal and external focus strategies used during exercise on muscle activation, functional performance, and pain.

This research will make a methodological contribution to the literature through the objective evaluation of muscle mechanical properties using isokinetic assessment and the MyotonPRO device. The findings are expected to clarify the effects of attentional focus strategies on therapeutic outcomes in PFPS rehabilitation and have the potential to provide an evidence-based guide for physiotherapy practice. In this way, the study may contribute to the development of new approaches aimed at improving both clinical effectiveness and patient adherence.

Study Overview

• Status: Recruiting
• Conditions: Patellofemoral Pain, PFP
• Intervention / Treatment: Other: Internal focus group; Other: External focus

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: SEDA ATEŞ, Bachelor degree; Phone Number: 90+ 5388543087; Email: seda.ates@ogr.iuc.edu.tr

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Recruiting
    • Istanbul University-Cerrahpasa

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Aged between 18 and 45 years.
• Diagnosed with patellofemoral pain syndrome (PFPS).
• Anterior or retropatellar knee pain persisting for at least four weeks with a VAS score > 3.
• Pain exacerbated by at least two functional activities (e.g., squatting, stair climbing, prolonged sitting).
• Willing to regularly participate in the 6-week program throughout the study period.

Exclusion Criteria:

• History of patellar subluxation or dislocation.
• Anterior or posterior cruciate ligament insufficiency.
• Lower extremity fractures.
• Neurological or systemic musculoskeletal disorders.
• Rheumatoid arthritis or other inflammatory joint diseases.
• History of knee surgery, meniscal injury, or any other underlying musculoskeletal condition that would prevent the participant from performing the exercises.
• Pregnancy or postpartum period.
• Participation in a similar exercise program within the last 3 months.
• Radiographic evidence of osteoarthritis classified as Kellgren-Lawrence grade 2 or higher.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Internal focus	Other: Internal focus group; Internal focus refers to directing attention to one's own body movements or muscle activity while performing a task (e.g., focusing on contracting a specific muscle). During isokinetic strength exercises, this group is instructed with commands such as: "Tighten your quadriceps" and "Straighten your knee."
Experimental: External focus	Other: External focus; External focus refers to directing attention to the effect of a movement on the environment or an external object, rather than on the body itself. During isokinetic exercise, this group is given the instruction: "Increase and maintain the performance indicator on the screen."

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Kujala Patellofemoral Pain Score	Kujala Patellofemoral Pain Score is a valid and reliable self-reported outcome measure specific to patellofemoral pain syndrome that assesses knee function and pain-related limitations during daily activities. The total score ranges from 0 to 100, with higher scores indicating better knee function and fewer symptoms.	baseline
Kujala Patellofemoral Pain Score	Kujala Patellofemoral Pain Score is a valid and reliable self-reported outcome measure specific to patellofemoral pain syndrome that assesses knee function and pain-related limitations during daily activities. The total score ranges from 0 to 100, with higher scores indicating better knee function and fewer symptoms.	Week 3 of the Treatment
Kujala Patellofemoral Pain Score	Kujala Patellofemoral Pain Score is a valid and reliable self-reported outcome measure specific to patellofemoral pain syndrome that assesses knee function and pain-related limitations during daily activities. The total score ranges from 0 to 100, with higher scores indicating better knee function and fewer symptoms.	Week 6 of the Treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visual Analog Scale	Visual Analog Scale (VAS) is a simple and reliable tool used to assess the intensity of knee pain. Participants rate their pain on a 0 to 10 cm scale, with higher scores indicating greater pain severity. It was used to evaluate changes in pain before and after exercise.	baseline
Visual Analog Scale	Visual Analog Scale (VAS) is a simple and reliable tool used to assess the intensity of knee pain. Participants rate their pain on a 0 to 10 cm scale, with higher scores indicating greater pain severity. It was used to evaluate changes in pain before and after exercise.	Week 3 of the Treatment
Visual Analog Scale	Visual Analog Scale (VAS) is a simple and reliable tool used to assess the intensity of knee pain. Participants rate their pain on a 0 to 10 cm scale, with higher scores indicating greater pain severity. It was used to evaluate changes in pain before and after exercise.	Week 6 of the Treatment
Isokinetic Muscle Strength Assessment (Isoforce)	Muscle performance will be objectively evaluated by measuring concentric strength values of the quadriceps muscle.	baseline
Isokinetic Muscle Strength Assessment (Isoforce)	Muscle performance will be objectively evaluated by measuring concentric strength values of the quadriceps muscle.	Week 3 of the Treatment
Isokinetic Muscle Strength Assessment (Isoforce)	Muscle performance will be objectively evaluated by measuring concentric strength values of the quadriceps muscle.	Week 6 of the Treatment
Muscle Tone	Muscle tone was assessed using the MyotonPRO device, expressed in Hertz (Hz), with higher values indicating increased resting muscle tone.	baseline
Muscle Tone	Muscle tone was assessed using the MyotonPRO device, expressed in Hertz (Hz), with higher values indicating increased resting muscle tone.	Week 3 of the Treatment
Muscle Tone	Muscle tone was assessed using the MyotonPRO device, expressed in Hertz (Hz), with higher values indicating increased resting muscle tone.	Week 6 of the Treatment
Muscle Stiffness	Muscle stiffness was measured using the MyotonPRO device, expressed in Newton per meter (N/m), with higher values indicating greater muscle stiffness.	baseline
Muscle Stiffness	Muscle stiffness was measured using the MyotonPRO device, expressed in Newton per meter (N/m), with higher values indicating greater muscle stiffness.	Week 3 of the Treatment
Muscle Stiffness	Muscle stiffness was measured using the MyotonPRO device, expressed in Newton per meter (N/m), with higher values indicating greater muscle stiffness.	Week 6 of the Treatment
Muscle Elasticity	Muscle elasticity was evaluated using the MyotonPRO device, expressed as logarithmic decrement, with lower values indicating better elastic properties.	baseline
Muscle Elasticity	Muscle elasticity was evaluated using the MyotonPRO device, expressed as logarithmic decrement, with lower values indicating better elastic properties.	Week 3 of the Treatment
Muscle Elasticity	Muscle elasticity was evaluated using the MyotonPRO device, expressed as logarithmic decrement, with lower values indicating better elastic properties.	Week 6 of the Treatment
Step-Down Test	Step-Down Test was used to assess lower-extremity control and functional performance. Participants were instructed to perform as many step-down repetitions as possible within 30 seconds. Performance was recorded as the number of completed repetitions, with higher scores indicating better functional capacity and dynamic knee stability.	baseline
Step-Down Test	Step-Down Test was used to assess lower-extremity control and functional performance. Participants were instructed to perform as many step-down repetitions as possible within 30 seconds. Performance was recorded as the number of completed repetitions, with higher scores indicating better functional capacity and dynamic knee stability.	Week 3 of the Treatment
Step-Down Test	Step-Down Test was used to assess lower-extremity control and functional performance. Participants were instructed to perform as many step-down repetitions as possible within 30 seconds. Performance was recorded as the number of completed repetitions, with higher scores indicating better functional capacity and dynamic knee stability.	Week 6 of the Treatment
Single-Leg Hop Test	Single-Leg Hop Test was used to assess functional performance and dynamic knee stability. Participants were instructed to perform a maximal forward hop on the affected limb. The hop distance was measured in centimeters (cm), with greater distances indicating better functional performance.	baseline
Single-Leg Hop Test	Single-Leg Hop Test was used to assess functional performance and dynamic knee stability. Participants were instructed to perform a maximal forward hop on the affected limb. The hop distance was measured in centimeters (cm), with greater distances indicating better functional performance.	Week 3 of the Treatment
Single-Leg Hop Test	Single-Leg Hop Test was used to assess functional performance and dynamic knee stability. Participants were instructed to perform a maximal forward hop on the affected limb. The hop distance was measured in centimeters (cm), with greater distances indicating better functional performance.	Week 6 of the Treatment

Collaborators and Investigators

• Sponsor: Istanbul University - Cerrahpasa
• Investigators: Study Director: SEZEN KARABÖRKLÜ ARGUT, Assistant Professor, Istanbul University-Cerrahpaşa, Faculty of Health Science

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2026
• Primary Completion (Estimated): September 2, 2026
• Study Completion (Estimated): September 2, 2026

Study Registration Dates

• First Submitted: December 17, 2025
• First Submitted That Met QC Criteria: January 26, 2026
• First Posted (Actual): February 3, 2026

Study Record Updates

• Last Update Posted (Actual): February 11, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Joint Diseases; Patellofemoral Pain Syndrome
• Other Study ID Numbers: 2025/714

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No