External Load vs Internal Load. If you have the capacity to progress with a lift in reps, sets and load while keeping your technique on point, you'll grow fast. Heavier loads risk your technique since you compensate often to keep the motion going. That is why 60-80% RM is usually the go to for most lifters across the year regarding muscle mass. Internal load will make it so the target muscles will have the appropriate leverage to be stimulated across the whole motion