Hopefully you're all toned up now that you've gotten through Shape Up - Backside, and you're ready to take it up a step and try some new sets. In Maximize - Back in Action we're using the same muscle groups, the back, biceps, glutes, hamstrings, and, as always, the abs. But we'll be incorporating a whole new set of exercises and working in cardio intervals to keep your heart rate up and really burn off the fat.