Today we announced Xbox Fitness is coming to Xbox One. The extensive library of videos from the world’s biggest fitness brands including Beachbody’s P90X (Tony Horton) and INSANITY (Shaun T), Jillian Michaels, Tracy Anderson and others, will be available for free with Xbox Live Gold memberships through December 2014. Using Kinect technology, Xbox Fitness can read your heart rate without a monitor, 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.
I posted more screenshots on my Skydrive
More details about Xbox Fitness on Xbox.com