When you load the lower weight horns on the Pendulum Squat Pro it is easier to raise the weight from a low squat position and more difficult to continue as the weight ascends. The exercise is very similar to hanging chains on an Olympic barbell. Chains are hung from bars to alter the strength curve making an exercise more difficult at the top of the movement. The difference between the Pendulum Squat Pro and a barbell with chains is that the Pendulum floating yoke changes resistance with the body lever system keeping the stress on the legs and hips and off the lower back during the movement. Get Strong without adding chains and squat like a Pro.