Muscle fibre types and contractions

1. Muscle Fibre Types And muscular contractions

2. Key Concepts Muscles consist of slow-twitch and fast-twitch fibres. These fibres are suited to certain types of physical activity and assist with an athlete’s capacity to create forceful or sustained muscle contractions. Muscle contractions can be isotonic (concentric and eccentric) and isometric

3. Muscle fibre types There are two basic types of muscle fibres we have in the body Fast twitch (2 types) and slow twitch Most people would have about a 50:50 split of the two different types Each fibre is better suited to a different type of activity (based on its intensity)

4. Slow Twitch (Type 1 fibre ) Red in colour Contract slowly over a longer period of time Best suited to aerobic and endurance type activities Exert less force and can contract repeatedly

5. Fast Twitch (Type 2a) Very similar characteristics to Slow Twitch fibres Have the ability to contract very forcefully over a longer period of time

6. Fast Twitch (Type 2b) While in colour Contract rapidly over a shorter period of time Best suited to anaerobic and high intensity activities Exert great force in bursts of power and speed

7. Athletes and their fibre types

8. Types of muscle contractions

9. Overview There are three types of muscles contractions classified by the movement they cause Isotonic Isometric

10. Isotonic The most common type of contraction Occurs when there is a change in muscle length as tension is developed Muscle is shortening = isotonic concentric Muscle is lengthening = isotonic eccentric

11. Isometric This type of contractions is characterised by the muscle contracting without causing movement. Example: Holding your body in a squatting position It is quite difficult to maintain this contraction for a long period of time