Characteristics of fast and slow twitch muscle fibres Flashcards
describe how muscle fibres can effect a sportsperson
most people have an imbalance of all three types, however individuals who have a high percentage of a particular type are genetically advanced towards particular activities
how does training effect muscle fibres?
training can develop the abilities of different fibres but it cannot change one type of muscle fibre into another type of muscle fibre
what are the different types of muscle fibres?
-slow twitch
-fast twitch
what are the different types of fast twitch fibres called?
-Type IIa
-Type IIx
what is a slow twitch fibre called?
Type I
describe Type I muscle fibres
-small in size, these fibres take a relatively long time to contract
-have a good oxygen supply and is why they are a deep red in colour so designed to work aerobically
-they contract slowly, but can work for long periods without tiring
-not particularly powerful
what events are Type I muscle fibres suited for?
suited to endurance events and not suited to high intensity
describe Type IIa muscle fibres
-designed to work anaerobically
-they contract quickly with high force
-can work for a relatively long time
-suited to dynamic and fast paced activities lasting 30 seconds to 2 minutes
-good strength and speed endurance
-fibres are not as fatigue resistant as Type I and not as powerful as Type IIx
describe Type IIx muscle fibres
-pure fast twitch fibres
-designed to work anaerobically
-contract very quickly with huge force
-can only work for a very short intensity
-explosive fibres with a big power output
-high anaerobic capacity
-very low aerobic capacity/low fatigue resistance
what events are Type IIx muscle fibres suited for?
suited to very fast activities e.g. shot put
what percentage of each fibre does an average person possess?
60% slow twitch
40% fast twitch
