Start: Stand in front of a sturdy step or bench with a barbell resting on your traps. Put your nondominant foot flat on the step-that's the leg that's going to do the work. Make sure your lower back is in its naturally arched position, your shoulders are pulled back, and your eyes face forward.
Finish: Push down through your working heel to lift your other leg and brush the step with that foot. Then return to the starting position. It's important to keep all your weight on your working foot-your other foot is just along for the ride. Finish the set, then switch and do the same number of repetitions with your dominant foot on the step.
Stand sideways to one side of a step with the barbell on your back. Step up with the foot that's the farthest from the step, crossing that foot in front of your other leg. Push up with the crossing leg and just drag the other along for the ride. Then return to the starting position. When you finish all the reps with one leg, move to the other side of the step and step up and across with your other leg. Don't try this with a lot of weight until you're comfortable with the movement.