Muscular System

1. Muscular System

2. Fitness for activities Muscles What is the role of muscle? In order to make the joints move, muscles are required. The muscles in the body can pull. Combined with the joints, this allows us to move.

3. Fitness for activities Muscles We need to know the names of some of the muscles so, here goes!

4. Fitness for activities Muscles Biceps

5. Fitness for activities Muscles Pectorals

6. Fitness for activities Muscles Deltoids

7. Fitness for activities Muscles Abdominals

8. Fitness for activities Muscles Quadriceps

9. Fitness for activities Muscles And at the back! Trapezius

10. Fitness for activities Muscles Deltoids

11. Fitness for activities Muscles Triceps

12. Fitness for activities Muscles Latissimus dorsi

13. Fitness for activities Muscles Gluteals

14. Fitness for activities Muscles Hamstrings

15. Fitness for activities Muscles Gastrocnemius Also known as calf muscles

16. Fitness for activities Muscles So, in summary, all the muscles that you need to know which are visible from the back are: Trapezius Deltoids Triceps Latissimus dorsi Gluteals Hamstrings Gastrocnemius

17. Fitness for activities Muscles And, in summary, all the muscles that you need to know which are visible from the front are: Deltoids Pectorals Biceps Abdominals Quadriceps

18. Fitness for activities Muscles • There are three different types of muscle: • Cardiac muscle • Involuntary muscle • Voluntary muscle

19. Fitness for activities Muscles • There are three different types of muscle: • Cardiac muscle • Cardiac muscle is only found in the heart. • Without any conscious effort, it repeatedly contracts and then relaxes throughout your life.

20. Fitness for activities Muscles • There are three different types of muscle: • Involuntary muscle • These muscles also work without any conscious effort. • However, they do not work continuously. • They are found around organs such as the intestines and blood vessels.

21. Fitness for activities Muscles • There are three different types of muscle: • Voluntary muscle • Voluntary muscles are under your own control. • They are attached to your skeleton.

22. Fitness for activities Muscles How do muscles pull bones? For a muscle to pull successfully, it must be attached to two bones which are pivoted about a point.

23. Fitness for activities Muscles How do muscles pull bones? For a muscle to pull successfully, it must be attached to two bones which are pivoted about a point. Here the muscle in red pulls inwards with forces applied to the shoulder and forearm as indicated by the blue arrows.

24. Fitness for activities Muscles How do muscles pull bones? The muscles are attached to the bones by tendons. The tendons will attach each muscle to two bones. One bone will be fixed so that as the muscle pulls, the other bone moves. Notice the pivot point

25. Fitness for activities Muscles How do muscles pull bones? The point where the muscle is attached to the stationary bone is called the origin.

26. Fitness for activities Muscles How do muscles pull bones? The point where the muscle is attached to the bone that moves is called the insertion.

27. Fitness for activities Muscles How do muscles pull bones? Here, we are looking at how the biceps are used to raise the forearm. There is, of course, the problem of lowering the forearm. We have said that muscles only pull and clearly, the biceps’ pull only raises the forearm!

28. Fitness for activities Muscles How do muscles pull bones? This is the job of the triceps which are attached to the forearm on the other side of the pivot. If the triceps pull, the forearm is lowered. Biceps Triceps

29. Fitness for activities Muscles How do muscles pull bones? This is the job of the triceps which are attached to the forearm on the other side of the pivot. If the triceps pull, the forearm is lowered. Biceps Triceps What we have actually done here is described how muscles work in pairs. These pairs of muscles are called antagonistic muscles.

30. Fitness for activities Muscles How do muscles pull bones? Antagonistic muscles As one of the muscles pulls (contracts), the other one relaxes (extends). In this case the triceps pull as the biceps relax. Biceps Triceps

31. Fitness for activities Muscles How do muscles pull bones? Antagonistic muscles The relaxing muscles, the antagonists, in this case, are the biceps. Biceps Triceps

32. Fitness for activities Muscles How do muscles pull bones? Antagonistic muscles The contracting muscle which is pulling is called the prime mover. It is the one that is causing the motion! Another name for the prime mover is the agonist. Biceps Triceps

33. Fitness for activities Muscles How do muscles pull bones? Antagonistic muscles It is, of course, essential that the shoulder remains stationary. This is achieved using special muscles called synergist muscles. Biceps Triceps

34. Fitness for activities Muscles How do muscles pull? If a muscle contracts, it is easy to see that it will make something move (provided that one end of it remains fixed in position). This is called isotonic contraction. Any exercise that makes a part of the body move is caused by isotonic contraction.

35. Fitness for activities Muscles How do muscles pull? However, muscles are used without movement occurring. In this case, there cannot be contraction of the muscle – otherwise there would be movement! This is called isometric contraction.

36. Fitness for activities Muscles Do all muscles do the same thing? No, there are two types of muscle fibres which behave in different ways. 1 Fast twitch muscles Fast twitch muscles will contract very quickly and with great force. They are powerful muscles. However, they tire very quickly. Sprinters will have many, well-developed fast twitch muscles. They need to be able to do work quickly for short periods of time.

37. Fitness for activities Muscles Do all muscles do the same thing? No, there are two types of muscle fibres which behave in different ways. 2 Slow twitch muscles Slow twitch muscles will contract more slowly and with less force. They are less powerful muscles. However, they don’t tire so quickly. Long distance runners and cross country skiers will have well-developed slow twitch fibres to give them stamina.