During squatting, what amount of body weight is transmitted through the PFJ?

During squatting, what amount of body weight is transmitted through the PFJ?

• A. 5x
• B. 7x
• C. 3x
• D. 2x

Answer: (B)

PFJ loads during squatting rise with knee bend, so the joint bears a very large compressive force as you go deeper into the squat. Biomechanical data show that in deep squats the patellofemoral joint can experience forces on the order of seven times body weight. This happens because, with greater knee flexion, the quadriceps must generate substantial force to control and move the load, which transmits through the patella to the femur; the contact area between the patella and femur also changes with angle, but the muscle force increases more than the contact area, raising the overall joint load. For shallower squats, the force is lower, around a few times body weight, but in deep squats it can reach about seven times. So among the options, seven times body weight best reflects the typical maximum PFJ load during squatting.

PFJ loads during squatting rise with knee bend, so the joint bears a very large compressive force as you go deeper into the squat. Biomechanical data show that in deep squats the patellofemoral joint can experience forces on the order of seven times body weight. This happens because, with greater knee flexion, the quadriceps must generate substantial force to control and move the load, which transmits through the patella to the femur; the contact area between the patella and femur also changes with angle, but the muscle force increases more than the contact area, raising the overall joint load. For shallower squats, the force is lower, around a few times body weight, but in deep squats it can reach about seven times. So among the options, seven times body weight best reflects the typical maximum PFJ load during squatting.