Slow twitch type 1 fibres contract slowly but can contract repeatedly over long periods. They have a good blood supply and are suited to endurance activity using the aerobic energy system which depends on oxygen from the blood for the supply of energy. Slow twitch fibres are much smaller and produce less force than fast twitch fibres. A Long distance Cycler would use mostly slow twitch fibres when cycling for 30 minutes at a low intensity.
Fast twitch type 2a fibres contract at a fast speed and can use aerobic energy sources as well as anaerobic energy sources. Fast twitch 2a fibres are of a white appereance due to the fact that they are less reliant on oxygen supplied by the blood for energy and this means they fatigue faster than slow twitch fibres.Fast twitch type 2a fibres are suited for speed, strength and power type related activities such as fast running events such as the 400metres sprint.
Fast twitch 2b fibres contract at a extremely rapidly rate,produce very forceful muscle contractions on the hand they fatigue quickly. Fast twitch 2b fibres are called white fibers like 2a fibres but they can only use anaerobic energy sources.
Both 2a and 2b fast twitch fibres are also suited to speed, strength and power type related activities but 2b Fibres are needed for shorter distance running activities such as 100metre sprints.
Fast twitch type 2a fibres contract at a fast speed and can use aerobic energy sources as well as anaerobic energy sources. Fast twitch 2a fibres are of a white appereance due to the fact that they are less reliant on oxygen supplied by the blood for energy and this means they fatigue faster than slow twitch fibres.Fast twitch type 2a fibres are suited for speed, strength and power type related activities such as fast running events such as the 400metres sprint.
Fast twitch 2b fibres contract at a extremely rapidly rate,produce very forceful muscle contractions on the hand they fatigue quickly. Fast twitch 2b fibres are called white fibers like 2a fibres but they can only use anaerobic energy sources.
Both 2a and 2b fast twitch fibres are also suited to speed, strength and power type related activities but 2b Fibres are needed for shorter distance running activities such as 100metre sprints.