Step ups are great for developing and shaping your butt. With this exercise you will do ten repetitions on one leg followed by ten repetitions with the other. Hold a dumbbell in each hand and position yourself in front of a bench. Place one foot flat on top of the bench positioning you body to make a right angle at your knee. Start with your chest held high and shoulders square step up through your heel and lightly tap the bench with your other foot before returning to your starting position. Breathing pattern for this exercise is to exhale as you step up and inhale as you step back down.Be careful to use a steady bench or aerobic step when performing this exercise. Beginners should do 2 sets of 10 repetitions on each leg, and those more advanced can do 3 sets of 10 repetitions.