muscle fibre types - lesson 6 Flashcards
1
Q
what are the 3 muscle types?
A
type 1
type 2a
type 2b
2
Q
describe the characteristics of type 1
A
- Slow contraction speed
- Low force production – small diameter/cross-sectional area of fiber
- High capacity for aerobic ATP production
- Fatigue resistant – able to contract repeatedly for continuous activity
- more aerobic characteristics such as high levels of myoglobin, mitochondria and capillarization, oxidative enzymes = need more oxygen
- Stimulated by relatively small motor neurons and are stimulated at a low frequency
- Red in color due to plentiful blood supply
- used for endurance activities = Marathon runner (up to 80% slow-twitch)
3
Q
describe the characteristics of type 2
A
- Fast-intermediate contraction speed
- High force of contraction
- Moderate fatigue resistance
- Generate greater force and more powerful contractions as they are larger than red fibers
- High anaerobic characteristics such as moderate to high levels of glycogen, PC and glycolytic enzymes (for anaerobic glycolysis i.e. lactic acid system)
- Stimulated by relatively large motor neurons and are stimulated at a moderate frequency
- Major fuel source is creatine phosphate and glycogen
- White in color
- used for speed endurance based activities = 400m/800m runner (up to 70% fast-twitch)
4
Q
describe the characteristics of type 2
A
- Fast-explosive contraction speed
- A very high force of contraction – larger diameter of the fiber
- High capacity for anaerobic ATP production
- Fatigue very quickly – low resistance to fatigue
- White in color due to very low blood supply
- Generate greater force and more powerful contraction as they are larger than red fibers
- Very high anaerobic characteristics such as high levels of glycogen, PCR, and glycolytic enzymes (for anaerobic glycolysis i.e. lactic acid system)
- Stimulated by very large motor neurons (required due to larger size of fibers) and are stimulated at a very high frequency
- used for speed, strength, and power-based activities = Sprinter (up to 80% fast-twitch)
5
Q
list the order of recruitment
A
low intensity = type 1
high intensity = type 2a
very high intensity = type 2b
