Firm up you bum, arms, stomach, back and chest with these incredible targeted exercises designed to sculpt and tone those problem areas ready for your wedding day! Do them three or four times a week to see results (and get a bum like Miranda Kerr's). Tone up your bum Glute raise 1. Lie on your back with your ankles below your knees. 2. Lift up your back creating a straight line from your shoulders, hips and knees. 3.