Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 52 2 2023 01 30 254 264 Ali Yalfani Department of Sport Injuries and Corrective Exercises, School of Sport Sciences, Bu-ali Sina University, Hamedan, Iran Mohamadreza Ahmadi Department of Sport Injuries and Corrective Exercises, School of Sport Sciences, Bu-ali Sina University, Hamedan, Iran 2022 04 03 2022 05 30 Background: Vertical ground reaction force (VGRF) can lead to the development knee osteoarthritis. This review systematic and meta-analysis aimed to investigate the VGRF in patellofemoral pain patients (PFP) during weight bearing tasks. Methods: Search strategy was conducted in databases: Science Direct, Scopus, PubMed and Google Scholar from Sep 2020 to Jun 2021. The VGRF components we measured were passive impact (Fz1)/peak and propulsion/active peak (Fz2). The quality of the studies was evaluated with Down and Black index and it was divided into three groups: low quality (LQ), medium quality (MQ) and high quality (HQ). The standardized mean difference between PFP and healthy individuals was used to calculate the effect size. Results: Nine articles were selected for systematic review and meta-analysis of which 5 studies was HQ, 3 studies were MQ and 1 study was LQ were classified. PFP compared to healthy individuals with moderate and small effect size have reduced impact and propulsion respectively.  Conclusion: The in PFP, VGRF is influenced psychological, behavioral and biomechanical factors. Therefore, psychosomatic therapeutic approaches may have a long time effectiveness on the rehabilitation of PFP.   https://ijph.tums.ac.ir/index.php/ijph/article/view/28311 https://ijph.tums.ac.ir/index.php/ijph/article/download/28311/7851