Slow-twitch fiber type percentage was correlated positively with grilling loss, whereas an inverse relation between fast-twitch fiber
type percentage and grilling loss was observed.
Although fast-twitch muscle fibers are usually larger in size than slow-twitch, slow-twitch fibers can become up to 22% larger than fast-twitch fibers
with effective endurance training.
revealed (1) a shift to greater fast-twitch fiber
proportions in the contralateral leg vastus lateralis (VL) muscle based on ATPase staining and (2) a reliance on anaerobic metabolism with rapid lactate generation during isolated contralateral or hemiparetic limb exercise in contrast to the oxidative metabolism during isolated ipsilateral leg exercise .
Muscle fibers that contract rapidly are known as fast-twitch fibers
activate and deactivate rapidly and come in two types: "Type 2A muscle fibers" which fatigue at an intermediate rate, and "Type 2B muscle fibers" which fatigue rapidly.
Scientists believe that the speediest sprinters may have an even higher percentage of fast-twitch fibers
than the average racehorse.
Doing Pilates and regular crunches will recruit your slow-twitch and sometimes your medium-fast-twitch muscle fiber types, but you have another muscle fiber type called your fast-twitch fibers
that also need to be recruited.
In both macaques and people, myosingene products appeared only in a class of muscle fibers known as fast-twitch fibers
And that can cause your fast-twitch fibers
to be used inefficiently, and even to atrophy in some cases.