Patellofemoral pain,there are many factors to consider including quadriceps strength and function, foot motion and mobility, muscle flexibility, pain sensitivity, and most importantly load management.

What happen when hip loss strength?

The hip controls half of the patellofemoral joint.Patellofemoral pain is thought to be caused by too much lateral tracking of the knee cap on the thigh. 

Importantly, thigh motion is controlled by the hip joint, and research has shown us that greater rolling in motion at the hip leads to greater lateral tracking of the knee cap in people with patellofemoral pain.