Leg Extension-MachineMain Muscle: QuadricepsOther Muscles: NoneMechanics: IsolationSit on the seat of a leg extension machine and place your feet under the leg extension pad. Adjust the back pad so that your back can rest on the back pad. Adjust the foot pad so that your knees are at the end of the seat and the pad rests on the lowest part of your shins. Grab the handles on the side of the seat to prevent your bottom from lifting off the seat. Exhale as you extend the legs and pause when your legs are almost straight. As your quadriceps tighten, do not rock the bottom to bring the legs upward. As you inhale, slowly lower the legs to the starting position, following the same pattern. Do not swing the weight nor let the weight drop during the exercise. Be sure that all adjustable parts of the machine are tight before starting the exercise.