The primary muscles worked on this exercise are the quadriceps (front side of the legs).

Adjust the leg pads so they rest on your ankles. Fully extend your legs. Adjust the height of the bench unit as much as you need to keep your feet clear of the ground during the exercise.

Lower the weight slowly and retain the tension during the complete set by not letting the weight stack come together.

You can adjust the start position by adjusting the angle of the bench unit.