Preparatory hypertrophy seems to be the more fragile phase. If you stop training during the preparatory phase, your gains may disappear more rapidly16. If you make it to the myofibrillar phase, your chances of losing gains rapidly are probably much lower.

If you do leg presses for example, you directly cause muscle growth in the quads, meeting the criteria for hypertrophy specific training5. Doing very light squats that don’t themselves cause growth can also meet the criteria however, if you are practicing and developing technique that will later allow you to load squats enough to cause growth6.

Specificity directs Overload strategies.

Training for muscle size can potentiate strength, but there is no evidence for the potentiation of growth via strength gains nor any logical mechanism by which this could occur. If you want muscle growth, train for that. If you want strength, train for that. If you want some combination of the two, by all means train for both, just understand that

Multiple muscular biomechanical actions and ranges of motion exist

This means that “the pump” experience revered by bodybuilders through the ages is actually in some way a direct observation of stimulation of muscle growth.

Overload could also be interpreted as using more “load” than has ever been used before, but this is not actually a requirement of Overload either. More “load” than last time might be a more apt description.

The Principle of Specificity of Training: To improve at a specific sport or physical endeavor, training must either directly support or potentiate improved performance in that sport or endeavor.

Some are activated through the whole range, some at the stretched position, some at the contracted position, and some at various points between. Isometric training would only stimulate a fraction of these at a time. To stimulate as many units as possible, as much of the entire ROM as possible should be trained.