The 80/20 principal states that in any field, you can get 80% of results with only 20% of effort, and the last 20% will take the last 80% of the effort. This is meant to be encouraging that you can a lot of good results without having to dedicate all of your time and energy. When it comes to fitness, the 80/20 principle can be applied to build very straightforward routines that will work - if you’re able to stick with it long enough.