When you're exercising your front, don't neglect your back. "Working the upper back and chest at the same time will make the upper body more perky in general," Kalnes says. Place two dumbbells a little further than shoulder-width apart on the floor and grab on. Lift your body into plank position with your legs extra wide for balance. Bend your right elbow and pull the weight to your ribcage, balancing on your left hand. Lower the weight back down, then repeat with your left arm. This also works your core, Kalnes says. If it feels too challenging at first, you can start by balancing on your knees instead of your toes.