Progressive overload in strength training involves gradually increasing the number of working sets per exercise over time, from one set to three to six sets.

“you start increasing the load on the bar a little bit and if you're no longer getting sore or really tired and sore and tired in such a way that you need until next Thursday to get sore and tired you start increasing the number of working sets that you're doing because working sets wise up until this point was just one working set really if you think about it in the first week or two zero working sets they're all practice sets CU you're so untrained they're work sets for you but they're not to anyone else that's watching a few weeks in one work set a few weeks after two work sets and so on and so on and so on until you're doing anywhere between three and six working sets per exercise”