If huge muscle gains is your goal, working out with anything less than one hundred percent intensity of effort is not going to cut it.  In fact, it’s almost a complete waste of time.  Regardless of the actual intensity of effort required, working the largest of muscle groups will produce incredible muscle growth all over the entire body.

Although we may not be entirely sure why, we do know that without a doubt, it does happen.  For the best possible muscular gains,  the major muscular structures should be trained intensely.  If the exercise is intense, brief and infrequent, maximum gains will be achieved.  As no muscle can be truly isolated from the body’s subsystems and all exercises have some degree of overall effect on the body, for the best possible muscle gains, only full body workouts should be performed.

As I has explained to you here. Split-routines are in fact physiologically impossible.  A training program which ‘splits’ the body into muscle groups, doesn’t permit sufficient recovery time for the body overall.  As a result, split training programs do not produce maximum possible muscle gains.  In almost all cases, they actually prevent them. No exceptions.