How to achieve muscle hypertrophy to build muscle fast.

First i'd like to talk about the term hypertrophy.It is the excessive development of an organ/part.more precisely the increase in size by thickening of muscle fibers.
To achieve hypertrophy you must be staying within 8-12 rep.range for upper body and 15-25 rep range for the lower body.

Lower rep ranges are for building strength.If  you are staying within 3-5reps you will be gaining a lot of strength fast, but not as much mass.
This is the 4 time champion of the World's Strongest Man as you can see he doesn't have massive muscles and an amazing looking physique.









And this is a bodybuilder having much more massive muscles and being bigger at a much lower body fat %.










Lower reps fail to stimulate your muscles in the way that brings out hypertrophy.You must be using a weight that allows you to do a minimum of 8 reps and a maximum of 12.The only muscle in the upper body that needs a 15-25 rep range are the abdominal muscles.Lower body muscles require 15-25 rep range as well because your legs and abs are endurance muscles.