Stand tall with your back to a bench and a Smith Machine barbell resting across your back. Maintain a tight core and flat back as you carefully place your left foot on top of a bench behind you with toes facing down. Ensure the distance between yourself and the bench is not too great, otherwise the movement becomes more akin to a lunge than a split squat. Gripping the barbell firmly, bend the front knee as you drop the back knee, driving your hips back and down. Inhale as you do so. Ensure the front knee does not go over the toes and that the whole of the front foot remains in contact with the floor. Allow your thigh to come to parallel with the floor. Pause, then slowly return to the start position by extending the knee, but be sure not to lock it out at the top. Perform all the required reps on one leg before changing to the other.