Only on Xbox One, available free with an Xbox Live Gold membership through December 2014, the extensive library of videos from the world&rsquo;s biggest fitness brands includes P90X, INSANITY, workouts from Jillian Michaels, celebrity trainer Tracy Anderson and many others. Using precision Kinect technology, Xbox Fitness can estimate your heart rate, see which muscles are most engaged by measuring the power, force and transfer of weight in your body, and track the quality of your performance by measuring your balance, tempo and form. Some Xbox Fitness content is sold separately. See xbox.com/xboxfitness. ESRB Rating: EVERYONE