1. Lie face down on an elevated bunch, with your arms wrapped around the bench for stability, so that your knees are just past the edge of the bench and have the dumbbell resting below your legs on the floor. Pick up the dumbbell from the floor so that it rests between the arches of your feet. Bend your knees slowly upward, raising the dumbbell as close to 90 degrees as is comfortable. Take a short pause and slowly lower your knees back down. That's one rep.