Biomechanical effects of loading methods on the patellofemoral joint during stair climbing: based on statistical parametric mapping analysis

HCC particularly increased joint stress during single-support and second double-support phases, with concomitant increases in COP displacement distances and reduced lower-limb co-cativation indices (CCI) collectively compromising joint stability. Despite transient stress spikes during initial double-support, SLC maintained kinetic chain equilibrium through shorter external moment arms. These findings recommend prioritizing proximal symmetric loading modes complemented by targeted vastus medialis training to enhance patellar stability, thereby reducing both patellofemoral joint stress concentrations and low back pain risks.