If you want lean muscle like Nicky Hilton
you'll need to get that heart rate up. "Cardio is key for burning away those excess calories," says trainer Teddy Bass. "Try 25-40 minutes, three to five days a week varying the workout between treadmill, arc trainer, elliptical or even outside hikes, biking or a good run." Challenging your body with an ever-changing workout will give you the lean look you need for bikini season.