Humans have three main muscle fiber types
Type IIB
Type IIA
and
Type I
Type IIB are your "ultra fast twitch" muscle fiber types. World lass sprinters, and weightlifters and shotputters have high amounts of this fiber type
Type IIA is your "fast twitch" muscle fibers. This is the most abundant form of fast twitch muscles, and is what most "normal" people have. They do not produce force as quickly as IIB, but dont tire as easily. For a reason unkown to science, resistance training causes the body to change IIB into IIA fibers. Training with very heavy weights, or training for maximal explosion ( Olympic style) is the best way to maintain as much type IIB fibers as you can.
Type I is your "slow twitch" fiber types. They produce force very slowly, but they have lots of hemoglobin in them. In animals this is known as "drak meat". Due to the rich hemoglobin content they can work for a long time without fatiguing. World class marathon runners, 10,00 meter runners, ironman athletes have high quantitites of this fiber type.
Which fiber is best for grappling is dependent upon your style of grappling/ fighting. A big strong powerful guy with lots of fast twitch muscles will probably have an explosive powerful game. A slow twitch guy will have a slower more methodical game plan
