This study aims to compare core muscle stability, postural balance, and flexibility between healthy women who regularly practice Pilates and those with a sedentary lifestyle. The researcher will evaluate if long-term Pilates practice (5 months or more) leads to significant improvements in physical performance compared to a lack of regular exercise. Assessment tools include the Pressure Biofeedback Unit (PBU) for core activation, the McGill battery for endurance, the Y-Balance test for dynamic stability, and the Sit-and-Reach test for flexibility.

This cross-sectional comparative study involves 55 healthy female participants divided into two groups: a Pilates group (minimum 5 months of practice, twice weekly) and a sedentary control group (less than 150 minutes of physical activity per week). To ensure objectivity and high-quality data, an "Assessor Blinding" protocol will be implemented, where the investigator performing physical measurements remains unaware of the participants' group allocation.

Primary outcomes include:

1. Deep muscle stabilization measured via a Pressure Biofeedback Unit (PBU) in a prone position.
2. Core endurance assessed using the McGill Core Endurance Battery (Flexor, Extensor, and Side Bridge tests).
3. Dynamic postural balance evaluated through the Y-Balance Test (YBT) in anterior, posteromedial, and posterolateral directions.
4. Static balance measured by the Single Leg Stance Test (SLST) with eyes open and closed.
5. Hamstring and lower back flexibility assessed by the Sit and Reach Test. Statistical analysis will be performed using IBM SPSS version 26.0 to compare the outcomes between the two groups.

Inclusion Criteria:

1. Healthy female volunteers aged 20-45.
2. For the Pilates group: having practiced mat Pilates, reformer Pilates, or any equipment-based Pilates discipline for at least 6 months; attending regular 60-minute sessions at least twice a week with a certified instructor.
3. For the control group: having a sedentary lifestyle (weekly moderate physical activity time less than 150 minutes).
4. Objectively demonstrating sedentary status using the International Physical Activity Questionnaire (IPAQ); only participants in the "low physical activity" category will be included in the control group.
5. Having full cognitive ability to understand, follow, and execute all physical assessment instructions.
6. Willingness to voluntarily sign the informed consent form prior to the study.

Exclusion Criteria:

1. History of any surgery involving the spine, pelvis, or lower extremities within the last 12 months prior to the study.
2. Currently pregnant or less than 6 months postpartum.
3. Diagnosed vestibular disorders or chronic clinical balance disorders.
4. History of neurological disease (MS, Parkinson's, etc.) or systemic metabolic disorder (diabetes, etc.).
5. Having a pain intensity greater than 2/10 on the visual analog scale (VAS) in the lower back or lower extremities.
6. Professional sports history or participation in other exercise programs exceeding 3 hours per week (excluding Pilates for the Pilates group).
7. Acute musculoskeletal injuries or acute illnesses that may affect energy levels on the day of evaluation.
8. Concurrent participation in other intensive core strengthening programs such as "advanced yoga" that may affect results.

Healthy adult women from the general community and Pilates studios in Istanbul, Turkey.

Individual participant data will not be shared to ensure the privacy and confidentiality of the participants, as per the ethical approval guidelines of Istinye University. The aggregated results will be published as part of the Master's thesis and potential academic publications.