Training Principles
Progressive Overload
Also written: overload principle
Gradually asking your body for a little more than it's used to, so it keeps adapting.
Your body only changes when it’s challenged. means you keep raising the challenge a little at a time: more weight, more reps, more sets, less rest, or better technique.
The key word is gradually. Too small a step and nothing changes. Too big a step and you get hurt or burn out.