This clinical trial aims to determine the optimal frequency of exercise therapy for improving pain, function, and quality of life in participants with patellofemoral pain. The main questions it aims to answer are:

Does exercising twice a week provide the same benefits as exercising three times a week for individuals with patellofemoral pain? What are the optimal dosage, volume, and weekly exercise frequency for treating patellofemoral pain?

The investigators will compare two groups of participants: one group of participants receiving exercise therapy twice a week and another group receiving exercise therapy three times a week. Both groups will follow the same exercise protocol targeting the muscles of the hip and knee joints.

Participants:

84 volunteers (both male and female) with patellofemoral pain Physically active individuals aged between 18 and 40 years

Interventions:

Participants will be randomly assigned to one of two groups Both groups will perform the same exercises for hip and knee muscle strengthening Group A will exercise three times per week Group B will exercise two times per week The intervention will last for six consecutive weeks

Assessments: Participants will be evaluated at the following time points:

Before the intervention After the 4th and 6th week of intervention 6 months and 1 year after the end of the intervention

The primary Outcome Measure will be pain intensity.

Secondary Outcome Measure:

Anterior knee pain during daily activities Kinesiophobia Pain-related self-efficacy Chronic pain-related self-efficacy Catastrophizing Muscle strength 3D Movement analysis

Data Analysis:

The investigators will use an intention-to-treat analysis, which means that all participants will be included in the study, regardless of whether they completed the treatment as planned.

Appropriate statistical tests will be used to compare differences within and between the two groups, considering the time points and group factors.

A 5% significance level will be adopted, which means there is a 5% chance that the results are due to random variation rather than the treatment effect.

This clinical trial aims to investigate the optimal frequency of exercise therapy for individuals with patellofemoral pain. Current evidence supports exercise therapy as the first line of treatment for pain relief, improved function, and enhanced quality of life in individuals with patellofemoral pain. However, the most recent consensus on patellofemoral pain highlighted a gap in the ideal dosage, volume, and weekly exercise frequency for treating these individuals.

To address this gap, this study will compare two groups of individuals with patellofemoral pain who will undergo the same exercise program targeting the muscles of the hip and knee joints but with different frequencies. One group will perform the exercises twice weekly, while the other will do so thrice.

This randomized, controlled, double-blind clinical trial will recruit 84 physically active participants of both sexes, aged 18 to 40 years, who experience patellofemoral pain. Participants will be randomly and secretly allocated to one of two groups. Group A will perform the exercise protocol three times per week, and Group B will perform the same protocol twice weekly.

The intervention will last for six consecutive weeks. Participants will be evaluated at multiple time points: before the intervention, after the 4th and 6th week of intervention, and at 6 months and 1 year post-intervention. The evaluations will include pain intensity as a primary outcome, anterior knee pain during daily activities, kinesiophobia, pain-related self-efficacy, chronic pain-related self-efficacy, catastrophizing, muscle strength and 3d movement analysis as a secondary analysis.

The data analysis will follow the intention-to-treat principle, meaning all participants will be included in the analysis regardless of whether they completed the treatment as planned. Normality tests will be conducted to verify data distribution, and appropriate statistical tests will be used to compare differences within and between the two groups, considering time and group factors. A 5% level of significance will be adopted for statistical comparisons.

Inclusion Criteria: This study will include physically active individuals of both sexes, aged between 18 and 40 years, who have been experiencing patellofemoral pain and anterior knee pain for at least three months. Participants must have a score of at least three points on the Visual Analog Scale during any of the following activities: running, squatting, sitting for long periods with the knee bent, and climbing or descending stairs. Selection will be based on responses provided in the International Physical Activity Questionnaire.

Exclusion Criteria: Exclusion criteria include the following: a history of lower limb or spine surgery, patellar dislocation, anterior knee pain resulting from trauma, coexisting conditions in the knee joint such as meniscal and/or ligament injuries, lateral and/or posterior knee pain, cardiovascular issues or locomotion disorders that could impact the assessment, pregnancy, and a limb length discrepancy greater than 1 cm.