Figure 3. Considerations for open-kinetic-chain quadriceps resistance training with distal tibial load.

Performing quadriceps resistance training between 0-45 degrees of knee flexion with distal tibial load will produce higher patellofemoral joint stress and increase strain on the reconstructed anterior cruciate ligament (A), whereas performing resisted knee extensions in deeper levels of knee flexion will preferentially load the quadriceps tendon relative to the patellar tendon. Red arc, 0-45 degrees of knee flexion; yellow arc, >45 degrees of knee flexion; Black asterisk, quadriceps tendon autograft harvest site