Lie on your stomach on the machine, aligning the mid-point of your knee joint with the axis of rotation of the moving lever (arm) of the machine. Position the backs of the lower 1/3 of your lower legs under the resistance pads, avoiding contact with the pads at, or just above the heel. Lightly grasp any available handles to stabilize your upper extremity. Brace your abdominal muscles to stabilize your spine. Do not allow movement in your low back throughout the exercise.
Slowly exhale and bend the knees, using your hamstrings to pull your heels toward your butt. Avoid arching your back during this movement.
Continue the movement until your knees are bent more than 90 degrees, or your lower legs are aligned vertical to the floor, or the pads come close to touching your butt.
Pause briefly, then return to starting position in a slow, controlled manner. Repeat the movement.
Exercise Variation: Repeat the same exercise, but train each leg independently.
Improper technique will result in excessive recruitment (use) of the lumber extensors (low back muscles). Stabilize your low back throughout the exercise and use a lighter resistance if you are unable to control movement in the low back.