Tim McComsey, owner of TRyM Fitness, and Marzia Prince, Healthy Housewife and trainer, partner once again for a buddy workout focused on obliques, using a power ball medicine ball to really dig deep into those muscles. Stand about 3 to 4 feet apart, facing opposite directions. Twist and toss the ball to your partner who will catch and twist away before tossing the ball back. Do 12 reps and then switch the directions you are facing and do 12 more. Throw it harder to make it more difficult and work those obliques more. This is one fun partner exercise with the added bonus of plenty of cardio too.