This is a free piece of DLC and it gives you a 30 minute workout along with a 15 achievement. The workout is relatively low impact and focuses on strength, stamina and balance. To obtain the achievement, download the workout from the marketplace and once you get into the game, choose "Personal Training". Now pick "Update my program" and finally scroll through the list and select "G Series FIT workout with Gunnar Peterson". Choose to "Skip" the scanning of the bottle (or do it if you like) and then proceed through the workout. There are 12 routines total and it will take a little over the 30 minutes stated. The achievement unlocks at the end.