A Gem from Dr Ken
That said, be it high reps or low, progressive overload, consistently, over time, is what stimulates muscle tissue growth. Your body, despite the science that says "X number of reps is better for this, Y for that" will get stronger if it is overloaded. Dependent upon one's genetically determined ability to build muscle tissue "that shows" and supporting the stimulation with nutrition and rest, making the effort to overload in the many ways it can be done, is the answer to "getting mass" or "gaining strength". Over a lengthy period of lifting, your body will respond best if your are typical or average, from varying your reps. The level of intensity of the work and your consistency will be a lot more important than the reps you do.
- D Ken