Slow vs Fast Twitch

There are two different types of skeletal muscle fibres that are used to facilitate movement:

Slow Twitch Fibres

  • Slow twitch fibres are used for muscular endurance – they contract slowly but do not fatigue easily
  • Slow twitch fibres use oxygen for aerobic respiration, have a large amount of mitochondria and many blood vessels
  • Slow twitch fibres are typically red in colour due to the dense supply of capillaries
  • Slow twitch fibres are prevalent in endurance athletes, such as marathon runners

Fast Twitch Fibres

  • Fast twitch fibres are used for muscular strength – they contract rapidly but fatigue easily
  • Fast twitch fibres respire anaerobically and consequently possess less mitochondria and have fewer blood vessels
  • Fast twitch fibres are typically lighter in colour (white)
  • Fast twitch fibres are prevalent in strength athletes, such as sprinters

Slow Twitch versus Fast Twitch

twitch fibres