Jack Dempsey, Otto Arco, Maxick, The Great Gama, The Mighty Atom, Alexander Zass, Jasper Benincasa, Bruce Lee, Mas Oyama, Arnold Schwarzenegger, Dan Gable, Shaolin monks etc...
That, and more, is the list of people who used isometric exercises to gain a critical advantage in their fields. Muscle control, muscle mass, compound strength, tendon/ligament strength, speed, power, these are all things that isometric exercises can drastically improve if you train them daily.
And I'm improving them in only 6 minutes a day.
That's right, in only 6 minutes a day, I do exercises that I could do anywhere (traveling, a bathroom, literally anywhere my body goes), yet those exercises continue to develop maximal strength, mobility, and lean muscle mass.
I train each muscle from head to toe for 7-12 seconds daily. Now, you may be thinking, "wait, hold on. Isn't that overtraining?"
Because you're only training one repetition per muscle per day, even if the repetitions are high intensity, you are training your nervous system to sustain high loads without suffering the fatigue that you would from training repetitive movements daily.
Another important reason for daily training is the development of willpower. Though you'll develop considerable strength and lean muscle with these exercises, that is only the means to an end.
The ultimate goal is autonomy, to be able to have your mind take complete control over the strength of your body. That control will come with consistent, daily practice of the exercises. And to think you can get all that in 6 minutes!
"Remember the infinite is our inner freedom manifested through our consciousness." - Maxick