Photo credits: James Michelfedler.
1. Stand parallel to an aerobics step or other elevated surface that'll put your thigh at parallel to the floor when you place your foot on it.
2. Hold a dumbbell in each hand and step up onto the bench, leaving your trailing leg hanging off. Step back down but leave your lead leg on the box to begin the next rep. Complete all the reps on that side, then switch. That’s one set.