Not exact matches
Instead, it appears to be related to a much more fundamental metabolic constraint: the length of time required for the animal to reach its theoretical maximum speed, based on the number of «fast
twitch»
muscle fiber cells in the creature's
muscles, as compared to the length of time it takes for those cells to run out of readily available
energy.
And molecules that regulate the expression of genes may make athletes more
energy efficient, or help create more slow -
twitch muscle fibers.
In skeletal
muscle, fast -
twitch glycolytic
fibers use glycogen as the main
energy source for anaerobic metabolism, serving to sustain brief periods of high - intensity activity.
They believe that fast
twitch muscle fibers are less
energy - efficient than the slow
twitch ones and burn more
energy during workouts.
By supplying fast -
twitch muscle fibers with immediate
energy, creatine ensures that these
fibers don't prematurely fatigue and strengthens their contraction.
Creatine phosphate (creatines high
energy molecule form, stored within cells) is used to supply the type 11b
muscle fibers (fast -
twitch high - glycolytic; the ones that get largest in size) with immediate
energy, ensuring these
muscles do not prematurely fatigue 6.
Training at this intensity primarily uses slow -
twitch muscle fibers, since these
fibers provide more most of the mobility for events lasting 2 minutes or longer, workouts at this intensity should comprise most of your training.Training above this intensity will not significantly overload your slow -
twitch fibers, which you are attempting to train to become more efficient at using fat and oxygen to produce
energy while conserving carbohydrate stores.
The process of converting fat to
energy is essential for a healthy metabolism, and takes place in the slow -
twitch muscle fibers, the aerobic
muscle cell's mitochondria.
It's used in the fast
twitch muscle fibers as a source of
energy.
In general, Type I, red, slow
twitch muscle fibers are aerobic and burn primarily fat for
energy.
Fast
twitch muscle fibers (which fatigue quickly, but help with quick bursts of
energy) convert easily to the better slow
twitch muscle fibers that enable endurance exercises.