This study aims to investigate the relationship between knee joint range of motion and pain in patients with patellofemoral pain syndrome (PFPS). In a cross-sectional observational design, PFPS patients will perform trials involving progressively increased knee joint range of motion in three closed-chain exercises: squat, single-leg squat, and split squat. During each trial, participants will report pain levels on a 0-10 Visual Analog Scale (VAS) until either (1) achieving full depth in the respective exercise or (2) reaching a pain level of \>5 on the VAS.