Leg extension exercise is a great part of a complete leg workout. It focuses tension on the quadriceps specifically without utilizing gluteus or hamstring muscles like in a squat or leg press. Definitely something to keep in your tool box for leg development.
PreparationSit on machine with back against padded back support. Place front of lower legs under padded arm. Position knee joint at same axis as machine joint. Grasp handles to sides for support. Execution Move lever forward and upward by extending knees until legs are straight. Return lever to original position by bending knees. Repeat