1. More muscles … ugh
We’re almost there!! 

2. Learning goals We are learning to identify the types of muscle fibres.
We are learning to examine how to train each energy pathway.

3. MUSCLE FIBRE TYPE
certain muscles in our body are more adapted to one energy system than another according to the dominant type of muscle fibre in the muscle

4. TYPE 1 (SLOW-OXIDATIVE)
contract & relax relatively slowly
generate less force, but can last for longer
produce ATP aerobically because they contain high levels of:
fat (which can only serve as fuel for AEROBIC system)
blood vessels (which carry oxygen needed for AEROBIC)
myoglobin (the enzyme that stores oxygen in muscle)
mitochondria (site of AEROBIC)

6. TYPE II (FAST-TWITCH)
F-T fibres contract & relax 2-3 X as fast as slow-twitch
can generate explosive force, but only for short time
produce ATP anaerobically because these fibres contain high levels of:
phosphocreatine & glycogen (stored version of glucose) which serve as fuels for ANAEROBIC Systems
glycolytic enzymes (permit release of glycogen in muscle fibres)
larger motor units (so more fibres are recruited at once)

8. primarily dark meat
breast - white
legs - dark

9. TYPE II A (FAST-OXIDATIVE) vs TYPE IIB (FAST-GLYCOLYTIC)
Can actually distinguish between 2 types of FAST-twitch
IIA – contain both oxidative & glycolytic enzymes
Fast contractions, less fatigue resistant than type I
IIB – only glycolytic enzymes
Fastest contraction speed but limited fatigue resistance
The cool thing…IIB’s can become IIA’s if you train them through endurance training

10. Let’s watch!

11. most people have a relatively equal # of slow-twitch & fast-twitch fibres in their muscles
though certain areas of the body have more S-T (e.g. legs) and others have more F-T (e.g. arms)
elite level athletes however, tend to be born with an unequal ratio of fast-twitch & slow-twitch fibres
e.g., Usain Bolt = 80% f-t, Simon Whitfield = 80% s-t

12. I have more S-T
I have more F-T

13. Size
Contraction Speed
Fatigue Resistance
Color
Energy System
Mito-chondria
Slow Twitch (Type 1)
Small
Slow
High
Red
Aerobic
(Lots of O2)
Many
Fast Twitch (Type 2)
Large
Fast
Low
White
Anaerobic
(Little O2)
Few

14. Muscle fiber type Average person Sprint trained Aerobic trained Slow
Slow
(type I)
40%
55%
Fast
(IIa)
50%
20%
Super-fast (IIb)
10% 5%

15. training the energy systems
even though, our athletic performance is somewhat limited by our genetics (e.g., the ratio of Type I vs II muscle fibres), there are methods of improving the efficiency of our 3 Energy Systems
generally, an athlete should match training methods to the Energy System they use during competition

16. effects of TRAINING on the immediate alactic
All training for this system should be powerful (100% intensity) and short (6-12s). The recovery time for this system should be minimal (15s-120s).
Examples:
Running – 10 repetitions of 30m sprints with 30s recovery
Strength Training – 4 repetitions of 90% maximum load with 30s recovery
Swim – 8 repetitions of 25m sprints with 30s recovery
Effects of training on immediate alactic system:
20-40% increase of creatine phosphate stores
increase of ATP stores
increase in creatine kinase function

17. effects of TRAINING on the ANAEROBIC SYSTEMS
intense exercise lasting for up to 90 seconds will benefit hockey players, mid-distance runners by:
increasing glycogen stores in muscle
Enables oxygen to be used sooner
Increases speed of Cori Cycle
ANAEROBIC THRESHOLD – the point at which lactic acid is accumulating in the blood stream
Trained athletes have a higher AT (at 80-90% of max. effort) while untrained athletes have a lower AT (~55% of max. effort).

18. Let’s watch!

19. effects of training on THE aerobic SYSTEM
cardiovascular exercise lasting 40 min several times per week will benefit endurance athletes by:
increasing the # of arteries & veins (vascularization) in muscle tissue
increasing the # and size of mitochondria in muscle fibres
increasing the activity of the enzymes used in aerobic system (e.g. ATP synthase)
promoting fat as a fuel during exercise (instead of glucose) which saves muscles’ limited supply of glycogen

20. Let’s watch!

21. Learning goals We are learning to identify the types of muscle fibres.
We are learning to examine how to train each energy pathway.