1. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 1 Muscular functions

2. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system What you will learn about in this topic: 1. Muscle fibre types 2. Types of muscle contraction Muscular functions 2

3. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 3 Learning objectives By the end of this presentation you should be able to: Understand the different types of muscle fibres Describe how muscles work Explain muscle contractions

4. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system How muscles work Muscle can only pull. Because they cannot push, to make joints work they are arranged in pairs called antagonistic pairs. For muscles to move limbs, one muscle must pull (contract) and one must relax. Muscular functions 4

5. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system The pulling muscle is called the prime mover (or agonist). The muscle relaxing is called the antagonist. When a muscle contracts it becomes shorter. When a muscle relaxes it becomes longer. Muscular functions 5

6. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Synergists are muscles also involved indirectly with the action. They hold the body position so that the prime mover can operate. Muscular functions 6

7. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscle fibres There are two different types of fibre in muscles: 1. Fast twitch muscle fibres (FTMF) 2. Slow twitch muscle fibres (STMF) Everyone has a natural combination of these fibres in their body. Although the amount of fibres cannot be changed, they can be trained to work to their maximum capability. Muscular functions 7

8. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Each type is suited to different activities. Fast twitch muscle fibres are used for more explosive activities, which need quick reactions, or short bursts of energy, such as in discus and javelin. Muscular functions 8

9. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Fast twitch muscle fibres contract fast and produce a powerful action but have a limited oxygen supply so tire quickly. Muscular functions 9

10. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Slow twitch muscle fibres are used for endurance activities which are slow and prolonged, such as running, cycling and swimming. Muscular functions 10

11. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Slow twitch muscle fibres contract many times and stay efficient over long periods of time. Muscular functions 11

12. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscle contraction There are two different types of muscle contraction: 1. Isotonic 2. Isometric Muscular functions 12

13. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Isotonic muscle contractions occur when there is movement of the body. They happen frequently in games play. Muscular functions 13

14. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system The ends of the muscles move closer to make the action. As a muscle contracts (shortens and fattens), it causes concentric movement. When it relaxes, it is an eccentric movement (lengthens and flattens). Muscular functions 14

15. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Working the muscles isotonically improves dynamic (moving) strength. It develops cardiovascular and cardiorespiratory systems and increases power and endurance. Muscular functions 15

16. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Isometric muscle contractions take place when the muscle length stays the same and improves static strength. It is used for stabilizing parts of the body and holding it steady so that movement can take place elsewhere, such as a gymnast on a beam. Muscular functions 16

17. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system It does not develop power or muscular endurance; the cardiovascular and cardiorespiratory systems are not improved. Few sports require this type of contraction alone. Muscular functions 17

18. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Task Take a look at the following photographs and decide which muscle contractions are being used. Muscular functions 18

19. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 19

20. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 20

21. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Exam questions 1. Describe slow twitch muscle fibres. 2. Describe fast twitch muscle fibres. Muscular functions 21

22. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 22 What you have learnt in this topic: 1. Muscle fibre types 2. Types of muscle contraction

23. © Folens 2009 FOR EDEXCEL 1.2.4 A healthy, active lifestyle and your muscular system Muscular functions 23 Learning objectives You should now be able to: Understand the different types of muscle fibres Describe how muscles work Explain muscle contractions