Whenever I hear about Jillian Michaels, I’m taken back to circa 2009 when her fitness DVDs were sweeping the nation. It even convinced a cardio bunny like me to pick up a pair of dumbells and give strength training a go.  And I did love the results I saw with some of those DVDs (You can see my full review of one such DVD here.) But there was one problem: What do you do after you finish the videos? You can’t just do the same few workouts over and over again.  I mean, you can. But it gets pretty boring!  Despite Jillian Michaels having a whole library of fitness DVDs,…