I have been training about 4 years now, and I think I have tried everything. I have trianed everywhere from twice a week to seven times a week, I have tried always going heavy, and always going light, I have tried only doing power movements, and always doing isolation movements, I have tried long breaks between sets, and short breaks between sets, I have stayed in the gym for as long as 3 hours a day, and as little as 30 minutes a day...
and
I finally put together the perfect workout program. After years of reading this and that, and all these other people's training splits, and doing research on muscle recovery, etc. I finally found what gives me the most size and mass, in the shortest amount of time.

Some of you may recognize some other meathods mixed in with this, but I assure you, the split in its entirety is completely my own.

To lay it out simply at first, I have made some rules that I lift by.
1) Train no longer than 45 minutes a day
2) Only rest 12 breathes between sets
3) Keep all movements strict and controlled
4) During the set, never let the muscle rest, and do not allow momentum to come into play
5) Only train 4 days a week, to maximize recuperation time.
6) Only do 3 different excercises per muscle (example, 3 for the upper chest, 3 for the mid chest, 3 for the biceps, 3 for the triceps, etc)
7) Only do 3 sets per excercize
8) Always aim for the 8-12 rep range. Meaning, you can always do at least 8 reps, but cannot succeed in doing more than 12 reps
9) Flex or stretch your muscles between sets
10) Drink plenty of water

So, right off the bat, you may be asking how you can work all the muscles in only 4 days, with only 45 minutes to work.
Well, I will lend my training split as an example
Monday: Chest, Shoulders, and One set of Triceps
Wednesday: Back, Traps, and One set of Biceps
Friday: Legs
Saturday: Arms

Now believe it or not, none of this has been put together by random guessing, I have actually put all my knowledge to work simotaneously in this program.
For example,
1)College studies have shown that flexing/Stretching muscles between sets helps expand the overall relaxed size of the muscle, and helps to pump more blood into the muscle while not being directly worked.

2)Studies have proven that to maximize muscle stimulation for growth, at least 8 reps must be performed. But, Studies also include that after 12 reps, the body shuts down the "size" building process, and switches to endurance gains.

3)For building power with the lack of size gains, it is important to rest several minutes between sets, BUT, for BODYBUILDING, where you train not for power, but for overall size and developement, short (12 breathe) rest periods are required

4)It is a proven fact that most lifters over train. They let their ego take control, and have the natural thought process that "More is Better", this leads them to going to the gym 6 to 7 days a weeks, and doing way too many excercises, sets, and reps. So, they are off to a bad start by overworking the muscles, and make it worse by not taking enough time off to let the muscles fully recuperate.

5) Studies, along with overall experience, shows that although most muscles should only be worked once a week, the triceps and biceps require to be worked twice a week for maximum gains. That is why on My chest and Shoulder day, where the tricep has been worked secondary, I finish with one strictly tricep excercise, same as doing one bicep excercise at the end of my Back and Trap workout. While, still leaving a day at the end of the week to focus on arms alone.

The list goes on, but I assure you, I have done my research these past years.

It is a fact that "power movements" help build size and density. But, for full developement of a muscle, isolation exercises are needed.
That is why in my training program, I always start my muscle with a power movement, then move to more of an isolation movement, and then a complete Isolation movement.
For example.
For the mid chest. I would start with Flat Barbell Bench. Still focusing on 8-12 reps, and all the other rules I stated. Then, after 3 sets of Flat BB Bench, I move to 3 sets of Flat Dumbbell Bench, and finish it with 3 sets of Flat Flies.

Also, by only resting 12 breathes, only doing 3 excercises per bodypart, and only 3 sets per excercise, workouts are maximum intensity in a minimum time frame.

And when I choose the which excercises to do, and in which order, I choose carefully.
The Biceps for example. I start with incline Dumbbell curl. In the incline position, the bicep already has maximum stretch and tension on it. After orking it in this position, it wants to tighten away from being so stretched, so I move to the next closest excercise. I then do standing barbell curls. After being worked in the incline postion, the biceps have tightened to the point where a standing dumbell movement makes them feel just as stretched, with just as much continuos tension as the original incline curl. After I have tightened them beyond this point, I go to spider curls or preacher curls. This way, the bicep is as loose as possible while relazed, but thanks to the previous workouts, now feels just as tight, with just as much tension as the previous excercises.

As Charles Glass says, "Once a stick of dinomite has exploded, you cannot explode it again, its done"
Which means, once the muscle feels pumped, it is done, if you keep on pushing it, it will begin to tear down too much, and you have successfully overtrained it.

When I first started doing this, with only training 4 days a week, and 45 minutes a day, with such a low amount of excercises and sets, and to top it off, using lighter wieght than I was used to, so I could make to sure to keep perfect form, I simply felt like I was wasting my time. I felt like I was undertraining, and I wanted to do more. But, I was WRONG.
It worked WONDERS. I began to see gains on a regular basis, and have yet to hit a plateau. And that was all natural. Now, I am on my cycle, and it is even better.

I suggest that if you read this, you trust me, and try it for a couple of weeks, but try to go for 4 to 6 weeks. I gaurantee you will never look back. I have suggested this to other lifters, and all of them have had nothing but good things to say about the results they see.