Fast and Steady Muscle

In the picture

1. 1Badge 1 sits on the sprinter’s leading thigh.
2. 2Badge 2 sits on a pale elongated fibre in the left circular inset.
3. 3Badge 3 sits on the distance runner’s rear calf.
4. 4Badge 4 sits on a dark elongated fibre in the right circular inset.

Examples

• Sprinting 100 metres uses quick fibres that tire fast.
• Jogging for 30 minutes uses slow fibres that keep going.

Quiz: Fast and Steady Muscle (Age 13)

1. 1

   Which best describes the difference between the two muscle fibre types?

   • Fast fibres make quick, strong movements but tire quickly, while slow fibres work for a long time.
   • Fast fibres work for a long time, while slow fibres make quick, strong movements but tire quickly.
   • Fast fibres are used only for breathing, while slow fibres are used only for walking.
2. 2

   What does repeatedly doing one kind of training do to your muscles?

   • It makes your muscles rely more on the fibre type that fits that training.
   • It makes your muscles use both fibre types exactly equally no matter what.
   • It removes one fibre type completely after a few weeks.
3. 3

   If someone trains mainly with long, steady runs, which fibres would their muscles rely on more?

   • Slow, enduring fibres.
   • Fast, quick-tiring fibres.
   • Neither type, because muscles only use fibre type during races.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.