We program in three day cycles and therefore every fourth day is a rest day. We still have class on the fourth day of each cycle and it serves as a make up day if you missed one of the workouts. We program a three day cycle to maximize return on our efforts. Over the years and after trying many different work/rest variations coach Glassman determined that on day one most people are fresh and can do just about anything, day two they start to feel it but can still push pretty hard, and by day three they are getting tired but still have enough in the tank to do good work. One day off seems to be plenty to get you ready to go hard again. The three on, one off schedule is designed to maximize intensity and get the most out of each session. The athletes who follow it have great success and usually avoid over training. Try it, see what you think besides all the fitness benefits it also helps build community.