Naturally (people with no lifting experience) are like the control in the chart. Lots of type 2b. So when they need the muscle, its strong, but its not used very often.
Training changes what type of muscle fibers a person has. Lots of volume makes type 2a. Versus low volume, heavy weight makes type 2x and or 2b.
like i said above in my 1st or 2nd post in this thread YES you can improve your red or white muscle fibers by working them. however people are born with certain genetics which mean they will have an advantage with either
if you were born with tremendous white muscle fibers. but you only train red muscle fibers you might still be a great bodybuilder, but had you focused on powerlifting you could of been something more special for example.
genetics is definately a huge factor. a guy like Arnold or Samir Bannout have tremendous red muscle fibers, and they were able to take advantage of that. had they decided to become powerlifters they would of done good I'm sure, but they wouldn't of been champions like they were with Mr Olympia.
I like this thread a lot.. lets keep it going.. look what you did Radar just from a simple title lol.