This is for crazy schedules and limited equipment. I'm a musician and bartender, so I have to hit the gym just when it fits the schedule. That means sometimes I can go three days in a row, and sometimes I have to skip three days. That also means I need the 24 hour availability of a Planet Fitness, even with their limited equipment. The idea here is that it is set up in cycles, as in, every 5th exercise might be for the chest, but not necessarily that the chest would be worked with any more frequency on any given day. So, if you only have 20 minutes, you go in and hit whatever exercises you can in that limited amount of time. The next time you go, you simply pick up where you left off. That is why there are no particular days marked, it is just one long thread of exercises in order of targeted parts. That way, nothing gets ignored for too long as could happen in a traditional split format.