Begin by positioning yourself underneath a Smith Machine barbell. Make sure the bar is across your upper traps and not your neck. Stand with feet shoulder width apart, toes slightly turned out. Brace your core and keep your chest up. Bend first at the knees then at the hips, driving the hips back and down, inhaling as you do so. Lower slowly with control until your thighs are parallel to the floor or deeper depending on your range, making sure your knees are pointing in the same direction as your feet and that your lower back doesn't collapse. Return to the start position by extending at the knees and driving the hips forward. Exhale as you do so, squeeze your glutes at the top. Repeat.