Slow twitch: These muscle fibers are also known as Type 1. Slow twitch muscle fibers are generally fatigue resistant and have a high capacity for aerobic energy supply, but they have limited potential for rapid force development. They are red because all of the blood that goes through them due to their high level capillarizention. They are not easily injured and they can handle extreme amount of work and do not fatigue easily. Slow twitch muscle fibers rely on oxygen as their main energy source. These muscle fibers contract slowly and can be used for longer periods of time before they fatigue. Therefore, slow twitch fibers are great at helping athletes run marathons and bicycle for hours.
Fast glycolytic: Fast glycolytic or Type 2b are also fast twitch white muscle fibers but these muscle fibers have a very low tolarance to fatigue and need a high period of recovry after use. However, they are extremely powerful and explosive fibers and are the ones involved in activities like power lifting, the pitch of a Baseball, javelin throwing, shot putting, the beginning of a sprint, etc.
Slow oxidative fibers Fast oxidative-glycolytic fibers Fast glycolytic fibers
Type 1 (slow twitch oxidative) , type 2a (fast twitch oxidative) and type 2b (fast twitch glycolytic).
Slow Oxidative: These muscle fibers twitch at a very slow rate and are very resistant to fatigue. The peak force exerted by these muscles is also very low. Slow muscle fibers have a lot of oxidative enzymes but they are low in ATP activity. Slow oxidative fibers are used for aerobic activities Fast-glycolytic fibers: Some muscle fibers can contract at a fast rate and produce a large peak force while being resistant to tiring even after many cycles. These fibers are have a large ATP activity and are high in oxidative and glycolytic enzymes. These fibers are used for anaerobic activities that need to be sustained over prolonged intervals of time.
Slow Oxidative: These muscle fibers twitch at a very slow rate and are very resistant to fatigue. The peak force exerted by these muscles is also very low. Slow muscle fibers have a lot of oxidative enzymes but they are low in ATP activity. Slow oxidative fibers are used for aerobic activities Fast-glycolytic fibers: Some muscle fibers can contract at a fast rate and produce a large peak force while being resistant to tiring even after many cycles. These fibers are have a large ATP activity and are high in oxidative and glycolytic enzymes. These fibers are used for anaerobic activities that need to be sustained over prolonged intervals of time.
It depends on the type of skeletal muscle. Slow and fast oxidative fibers (type I and type IIa) may have many mitochondria. Fast glycolytic fibers (type IIx/IIb) have very few mitochondria. This is because in fast glycolytic fibers (type IIx/IIb) ATP can be produced outside of the mitochondrion in the cytosol of the cell due to high concentrations of glycolytic enzymes present in these fibers. In contrast, in oxidative fibers ATP is produced mostly within the mitochondrion, so more mitochondria are needed to to produce large amounts of ATP. Also, the number of mitochondria in these cells can increase with adaptations to exercise conditioning.
One that isn't needed for precise movement. Muscles that need precise control have motor units with more muscle fibers.
Slow oxidative fibers are typically red in color due to their high myoglobin content, which gives them their oxidative capacity for sustained contractions over long periods of time.
Fast Glycolytic
Slow-twitch fibers are also called red oxidative fibers. These fibers are more efficient at using oxygen to generate energy and are suited for activities requiring endurance and sustained low-intensity effort.
fast Glycolytic
Because it is oxidative and depends mainly on oxidative phosphorylation for energy.
Presence of myoglobin