This 20 second full exertion ( I do record the reps attained ) with a 10 second rest is really strenuous. I do 4 different exercises, back to back, then go through another round, for a 4 minute total time routine. I give a full 2 min cool down, then do it again, with 4 fresh exercises. It’s good to shake things up and use this technique, but I’ve found that the that it is too difficult for most clients and even my upper level clientele seem to have trouble making it through the 8 minutes. Any comments/thoughts/experiences that you can share ?