Gym? Never heard of it. Just kidding . . . but in all honesty, you don't always have to hit the gym to get in a good workout. If you're looking for something quick that will really fatigue your muscles,
Celebrity trainer Gunnar Peterson — yup, the one who trains the Kardashians, Kate Beckinsale, and the Los Angeles Lakers — wants to help you improve your core workout and make it as effective as possible.