I experimented for over a year, using static contraction training exclusively. This is training with the heaviest weights you can manage, over only the strongest range of your motion (the last inch or two of , say, a bench press.)
I would load the bar in my power rack, and squat it, press it, curl it, whatever, once per week! That was it- you need to let your "muscles rebuild"! says Pete Sisco, the expounder of the static contraction training principle...
I did indeed get so I could push, and support statically some very massive poundages. I think I gained the most, though, from pressing the bar into the pins of the rack, isometrically, for some seconds before letting up.
I also gained muscle mass, and fat. Most of the mass you'll gain using this method will be in your thighs, butt, chest and, unfortunately, your belly.
If you've ever seen Pete Sisco, you can envision what this training will do for you... think old Russian olympic lifter...
Before that, I used Superslow training system, wherein you lift a weight 10 seconds up, 10 seconds down. Very taxing, and very effective. But, again, Ken Hutchens, the originator, suggests you train perhaps one time per week... you will gain, but in the fashion of Static contraction/big butt/gut training. Ken was on the right trail, but he is reinventing the wheel...
John E. Peterson has never lost the training of the olden times; early 1900's era strongman training: isometrics, Visualized resistance (aka "muscle control"), calisthenics...
Visualized resistance, John calls it Dynamic Visualized Resistance, or DVR's, is particularly intrigueing:
You imagine, whilst moving your body through various movements, the resistance, and move in slow motion against your own, self-imposed resistance! Sounds wacky, but the more you practice it, the more control over your muscles, and the greater strength you get!
As near as I can tell, this was originally done my MAXICK, a german strongman from 100 years ago; he built his strength using this method exclusively. (And his physique, which was also amazing!) You can check him out on the MAXALDING website, which is what his training system was called.
Exercises are there, lots and lots of information; some of it fascinating.
I saw one photo of Maxick, holding a beer glass in one hand, holding a 240 pound man over his head with one hand, and not spilling the full glass of beer! I'll look for it, and post it when I do...
And Maxick only weighed about 150 pounds!! No fat butt/gut on this boy!!
So, check out the real deals; go back to the future!