Background <p>Patellofemoral pain (PFP) is a common musculoskeletal condition associated with strength deficits and altered lower-limb kinematics. Impaired “foot-core” function and foot–ankle mechanics may contribute to altered patellofemoral joint loading, but the added value of combining foot-core training with conventional hip–knee strengthening remains unclear.</p> Objective <p>To examine the effects of adding foot-core training to a hip–knee strengthening program on pain, function, strength, and three-dimensional step-down kinematics in individuals with PFP.</p> Methods <p>In this assessor-blinded randomized controlled trial, 40 participants with PFP were randomly allocated to an experimental group (EG; foot-core plus hip–knee strengthening; age 23.89 ± 1.58 years) or a control group (CG; hip–knee strengthening; age 22.94 ± 2.11 years) for 6 weeks. The primary outcome was the worst pain during daily activities measured with a visual analog scale (VAS). Secondary outcomes were function (Anterior Knee Pain Scale, AKPS), concentric isokinetic relative peak torque at 60°/s during hip extension/abduction and knee extension/flexion of the affected limb, and three-dimensional hip, knee, and ankle joint angles at initial contact (contralateral toe contact) during a single-leg step-down task. Outcomes were assessed at baseline and immediately post-intervention.</p> Results <p>EG demonstrated a greater reduction in post-intervention VAS than the CG (<i>P</i> = 0.022; ηp² = 0.135). AKPS was also higher in the EG than in the CG at post-intervention (<i>P</i> = 0.001; ηp² = 0.257). For step-down kinematics, the EG showed lower hip adduction (<i>P</i> = 0.001; ηp² = 0.676) and knee valgus (<i>P</i> = 0.001; ηp² = 0.525) than the CG, as well as greater ankle dorsiflexion (<i>P</i> = 0.002; ηp² = 0.805). In isokinetic strength outcomes, the EG exceeded the CG in quadriceps and hip abductor relative peak torque (both <i>P</i> &lt; 0.001; ηp² = 0.669 and 0.594), whereas hamstrings and hip extensors showed no between-group differences (<i>P</i> ≥ 0.398).</p> Conclusion <p>Adding foot-core training to a hip–knee strengthening program resulted in small additional improvements in pain and function and produced larger between-group effects in selected kinematic variables and strength outcomes. The clinical significance of these biomechanical changes requires further investigation.</p> Trial registration <p><a href="https://chictr.org.cn">chictr.org.cn</a>. NO: ChiCTR2400087664. Date 01/08/2024.</p>