Patellofemoral joint force and stress between a short- and long-step forward lunge

Controlled laboratory biomechanics study using a repeated-measures, counterbalanced design. To compare patellofemoral joint force and stress between a short- and long-step forward lunge both with and without a stride. Although weight-bearing forward-lunge exercises are frequently employed during rehabilitation for individuals with patellofemoral joint syndrome, patellofemoral joint force and stress and how they change with variations of the lunge exercise are currently unknown. Eighteen subjects used their 12-repetition maximum weight while performing a short- and long-step forward lunge both with and without a stride. Electromyography, ground reaction force, and kinematic variables were put into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle. Visual observation of the data show that during the forward lunge, patellofemoral joint force and stress increased progressively as knee flexion increased, and decreased progressively as knee flexion decreased. Between 70 degrees and 90 degrees of knee flexion, patellofemoral joint force and stress were significantly greater when performing a forward lunge with a short step compared to a long step (P