Vibroarthrographic analysis of patellofemoral joint arthrokinematics during squats with increasing external loads.

Background: The patellofemoral joint (PFJ) provides extremely low kinetic friction, which results in optimal arthrokinematic motion quality. Previous research showed that these friction-reducing properties may be diminished due to the increase in articular contact forces. However, this phenomenon has not been analyzed in vivo during functional daily-living activities The aim of this study was the vibroarthrographic assessment of changes in PFJ arthrokinematics during squats with variated loads.