Muscle fibre types

• Slow oxidative muscle fibres have high myoglobin content, high mitochondrial density, high capillary density, and small neurones with few fibres per neurone
• Fast oxidative glycolytic muscle fibres have moderate myoglobin content, moderate mitochondrial density, high capillary density, and large neurones with many fibres per neurone
• Fast glycolytic muscle fibres have low myoglobin content, low mitochondrial density, low capillary density, and large neurones with many fibres
• Muscle fibre types


  • Slow oxidative
  • Fast Oxidative Glycolytic
  • Fast Glycolytic
• Slow oxidative muscle fibres


  • High myoglobin content
  • High mitochondrial density
  • High capillary density
  • Small neurones
  • Few fibres per neurone
  • Low phosphocreatine stores
  • Low Glycogen stores
• Fast Oxidative Glycolytic muscle fibres


  • Moderate myoglobin content
  • Moderate mitochondrial density
  • High capillary density
  • Large neurones
  • Many fibres per neurone
  • High phosphocreatine stores
  • Moderate Glycogen stores
• Fast Glycolytic muscle fibres


  • Low myoglobin content
  • Low mitochondrial density
  • Low capillary density
  • Large neurons
  • Many fibres per neurone
  • High phosphocreatine stores
  • High Glycogen stores
• Recruitment of different muscle fibre types during different intensity exercise


  • Slow oxidative
  • Fast Oxidative Glycolytic
  • Fast Glycolytic
• Slow oxidative fibres are recruited first during low intensity exercise
• During moderate intensity exercise, slow oxidative fibres are recruited first, followed by fast oxidative fibres
• During high intensity exercise, oxidative fibres are recruited first, followed by fast oxidative glycolytic, then finally fast glycolytic
• Endurance performers (e.g. marathon runners)

  Have a higher proportion of slow oxidative fibres
• Characteristics of slow oxidative fibres


  • High capillary density
  • High myoglobin content
  • High fatigue resistance
  • High mitochondrial density
  • Create small amount of force
• Marathon runners also have some fast oxidative glycolytic fibres
• Marathon runners have very few fast glycolytic fibres
• Speed endurance performers (e.g. 400m/800m runners)


  Have a higher proportion of fast oxidative glycolytic fibres
• Characteristics of fast oxidative glycolytic fibres


  • High phosphocreatine stores
  • Large neurones
  • High capillary density
• Explosive activities (e.g. sprinters, long jump, javelin)


  Have a higher proportion of fast glycolytic fibres
• Characteristics of fast glycolytic fibres


  • Designed to work anaerobically with large PC stores
  • Create large amounts of force and power
  • High speed of contraction
  • Fatigue quickly
  • High anaerobic capacity
• Explosive activities will also have fast oxidative fibres
• Slow oxidative fibres will work first whilst picking up speed at the start of explosive activities
• Games players


  Have a mixture of slow oxidative, fast oxidative glycolytic and fast glycolytic fibres
• Slow oxidative muscle fibres


  • Small motor neurones stimulate few small muscle fibres
  • Create a motor unit producing small and slow forces over a long period of time
  • Resist fatigue
  • Good for sustained contractions
• Fast glycolytic muscle fibres


  • Large motor neurones stimulate many large muscle fibres
  • Create a motor unit producing a large amount of force quickly
  • Fatigue quickly
  • Good for brief exertions of large force