Muscle Fibres

• Give the 3 muscle fibre types

  • Slow twitch (Type 1)
  • Fast twitch (Type 2a)
  • Fast twitch (Type 2x)
• Type 1

  • Colour: Dark red
  • Myoglobin levels: High
  • Number of capillaries: High
  • Number of mitochondria: high
  • Aerobic/Anaerobic: high aerobic capacity
  • Fatigue resistance: high
  • Force of contraction: low
  • Speed of contraction: low
  • Sporting example: endurance events (10,000m, marathon running)
• Type 2a:

  • Colour: Pink
  • Myoglobin levels: moderate
  • Number of capillaries: moderate
  • Number of mitochondria: moderate
  • Aerobic/Anaerobic: both
  • Fatigue resistance: moderate
  • Force of contraction: moderate
  • Speed of contraction: moderate
  • Sporting example: 800m runner
• Type 2x:

  • Colour: white
  • Myoglobin levels: low
  • Number of capillaries: low
  • Number of mitochondria:low
  • Aerobic/Anaerobic: anaerobic
  • Fatigue resistance: low
  • Force of contraction: high
  • Speed of contraction: high
  • Sporting example: 100m sprint