Obviously no one can continue to add weight every session. So if your squat goes from 100kg x 20, next session you get 105kg x 16, then you aim for 17 or more and continue till you make 105kg x 20.
Now, if you get 105 x 16, then the following session is 105 x 16, you havent progressed, we simply do another set
Every session needs to contain one of the 3 "mores"
More reps, more weight, more sets. I dont care which one, but every session needs to be progressive
Any session repeated is a step backwards, your not holding your ground, youve gone backwards. This is the whole premise of our training, and why you see ordinary people lifting extraordinary weight.
Do you guys really think I dont get surprised when a 65yo man deadlifts 210kg then has a knee replacement 3 days later, you wonder why I dont listen to "injured" lifters, or when a 14yo squats 170kg, or a 64kg girl deadlifts 170kg, or a 75yo man deadlift 150kg.
These lifters aren't special, not even close, they just progress everytime they are in the gym.
This, is the key element in training, the one most dont understand