Study aim: The aim of this study is to determine the effects of whole body vibration and exercise therapy with exercise therapy alone on the parameters of flexibility, vertical jump, agility and pain in athletes with patellofemoral pain syndrome. Design: In this study, 24 patients with patellofemoral pain syndrome who have the inclusion criteria are select and randomly divided into two groups of intervention and control. Settings and conduct: In this study, the effect of whole body vibration and exercise therapy are investigated before and one month later the intervention on the vertical jump, flexibility, agility and pain and the location of the study is the Clinic of Yazd Medical Sports Medicine; this is also blinded that the examiner will not be aware of which intervention will be administered to which subject. The patients aware of the existence of two different groups, but do not know about their groups (intervention or control). Participants/Inclusion and exclusion criteria: Inclusion criteria are the people with antro or retropatellar pain, unilateral involvement, sports with leap and jump and exclusion criteria are history of dislocation or sublaxation of the patella, history of the hip, knee or ankle surgery. Intervention groups: The control group will undergo exercise therapy 3 times per week for four weeks; whereas intervention group undergo exercise therapy in addition to whole body vibration training 3 times per week for four weeks. Main outcome variables: Measured variables include: flexibility, vertical jump, agility and pain