Sex and body height influences on patellofemoral joint reaction force during stair ascent.

Background: Females are at greater risk of developing patellofemoral pain (PFP) than males, and an excessive patellofemoral joint reaction force (PFJRF) may contribute to this discrepancy. It is unknown if the PFJRF differs between males and females during stair ascent. Additionally, body height may also influence the PFJRF.