SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

HMS, BM EQ-Bank 32 MC

Which characteristic best describes Type IIb (fast twitch) muscle fibres?

  1. High mitochondrial density
  2. Slow contraction speed
  3. Rapid force production
  4. High fatigue resistance
Show Answers Only

\(C\)

Show Worked Solution

Considering all Options:

A. High mitochondrial density – INCORRECT

  • This is actually a characteristic of Type I (slow twitch) fibres
  • Type IIb fibres have relatively low mitochondrial density
  • This feature wouldn’t support their primary function of rapid force production

B. Slow contraction speed – INCORRECT

  • This is the opposite of Type IIb fibre characteristics
  • Type IIb fibres have fast contraction speeds
  • This is a characteristic of Type I (slow twitch) fibres

C. Rapid force production – CORRECT

  • Type IIb (fast twitch) muscle fibres are characterised by their ability to produce rapid, powerful contractions.
  • This is their primary distinguishing characteristic and function within the muscular system.

D. High fatigue resistance – INCORRECT

  • Type IIb fibres fatigue quickly
  • High fatigue resistance is a characteristic of Type I (slow twitch) fibres
  • Type IIb fibres’ rapid force production capability means they tire quickly

\(\Rightarrow C\)