Isometrics, as the name implies, involves holding difficult stretch positions. The add-on is that most of the positions also have a significant core and/or balance component. There were lots of yoga and core moves that were very interesting and challenging, as they were each held fro 45 seconds. Overall, great workout. Dynamix, I have mentioned before so I will not do so again, but suffice to say it is not a bad workout, but I think it could be better for the main stretch of the program
Accelerator is an awesome cardio workout. It is very similar to a Shawn T workout, with lots of cardio but with some upper and lower body engagement. It wiped me out, but I loved it. It is the type of workout I would definitely add as an extra workout if I ever want an extra little kick in the ass.