Insanity: The Asylum - Day 12

Once again I am met with the challenge of Back to Core. I know in looking at my videos from the previous days with this workouts that I'm improving, but during the workout it sure doesn't feel that way. Two moves in particular set my lower back on fire, and the first of those two does a number on my shoulders. Those two muscle groups continue to be my biggest area of weakness that I really want to improve on. The moves I am referring to are the twists (pulses included) and the swimmer. I had to take a quick break (I think a couple during the swimmer) in both of them to give myself some relief. The other thing I am having issues with are my calf muscles during the jumping jack sequence. The same thing happened to me during Plyo and Legs & Back in P90X and it is quite painful. My calves have always been muscular, but ever since I strained my achilis a couple of years ago I have had this problem. I will have to monitor it and continue to stretch and massage them because it is pretty frustrating. Other than that, it was a great workout.