Sometimes you’re Rollin’ in the gym. You know how strong you are, you have a good feel for what weights to use for the sets/reps you are planning to work with. You’ve been progressing for awhile, and you have a great “Feel” or understanding of how much and how fast to progress so you can keep moving forward.
If you’re Rollin’ you can look at a Generic, Cookie Cutter routine like PHAT, PHUL, or Lyle McD. And you just Know how to run it and what weights to use, and how things fit together. You know enough, you can just Train.
Other times you’re lost and adrift in the gym. You can’t seem to enough momentum to start Rollin’. Everything is a grind. This is a bad time for 3 sets of 5.
You need to Learn what weights to use, and you need to Learn how to progress without pushing too hard. You gotta Learn how all the lifts fit into the program together. Then, you get a feel for these things, and start Rollin’ again. 5/3/1 will teach you how to load and how to byprogram. So you’re training, but you’re also learning How to train, so you’re more prepared for the future.