Mass Routines vs. Definition Routines

On a biological level, the generation of muscle growth in the form of muscle mass vs. muscle definition in the human body is determined by the activity of muscle fibers derived from the structure of one bodybuilding routine in regard to rep ranges. Let me explain.

All muscles are made out out of muscle fibers. Physical stress imposed on the body in the form of weight training or any other athletic activity actually tear up the muscle fibers in the body-part being stimulated. And after your muscle fibers tear after a workout, they rebuild to a larger size. This is a simplified account of how the process of actual bodybuilding works.

However, there are two types of muscle fibers. They are fast and slow twitch muscle fibers. Fast twitch fibers are stimulated mainly through explosive movements which require tremendous power. Slow twitch fibers on the other hand are stimulated when one engages in any type of endurance activity. As it relates to bodybuilding and weight training, the pathway to activating fast twitch muscle fibers involves lifting heavy weights for low reps. And contrary to this, slow twitch muscle fibers, which are more plentiful in the human body, become stimulated through executing exercises with high rep ranges and light weights.

Now what does all of this information have to do with difference between structuring a mass routine and a definition routine for bodybuilding you may be thinking? In one simple word; everything. You see, since there are more slow twitch fibers in the body, executing higher rep ranges during your workouts will grow the widest range of total muscle fibers, causing an optimal level of muscle separation amongst all of the muscles thousands of individual muscles in your body.

Now that you understand the science behind the foundation of definition routines, let me explain why lifting heavier weights for lower reps spurs on gains in muscle mass in one sentence. It is so because fast twitch muscle fibers when they are torn through engaging in a conducive bodybuilding routine grow to a larger extent than slow twitch muscle fibers. Simply put!