Old Timer: Quad sets are meant as a short term plan for most bb'ers. The extra high intensity is the main goal of this system. So, in a way, that could be called overkill. Taking a working muscle out of it's comfort zone, of the same old, same old, every workout into another advance level. Perhaps 4 to 6 weeks (the first week, one of a breaking in period for the CNS), based on twice a week, for some. But than again, lifting any kind of weight, would be considered overkill by the average non lifting person.
When approaching a workout with more serious intent, Quad sets (or other like intense efforts) can become the boost to mass, that most crave. One cycle, of 4 bicep exercise, should take 60 seconds (if that), depending on zero rest between exercises. And the body's ability adjust to this method at first. SS'ing with the triceps is another method, but a bit more advanced, when using Quad sets.
Quad sets can be used very well on all muscle groups. Arms and delts seem to always improve quite well. Though this type training is not always for eveyone. Like every thing else in training, nothing may work for all people. Good Luck.
