Muscle Fibre Types- Fast Glycolytic
The diameter of these muscle fibres is larger, this allows the athlete for example Patrick Johnson to have a higher contractile strength and speed which means that the athlete can have a stronger start when leaving the blocks giving him a stronger stride. They have a fast contracting speed due to the size and the strength; this works because more power is able to move quickly to the moving parts of his body.
The colour of the muscle fibres is white, this relates to the fact that he has a high anaerobic capacity This muscle fibre type also has many capillaries hence the red in colour. This relates to the fact that the athlete needs them to carry the blood to the working muscles and to be able to produce the energy aerobically throughout the race.
This system uses both the aerobic and anaerobic system to produce energy because the power they would need at the beginning and the ending of the race is produced anaerobically and when she needs a higher resistance to fatigue which is during the middle of the race it is produced aerobically.
If Kelly Holmes had more fast glycolytic fibres she would have too much power and fatigue quicker so she would then not be able to complete meaning that Johnson’s only able to work for under a certain amount of time without using oxygen. They have a high anaerobic capacity because they only compete for short periods of time; this means that they have a low number of mitochondria and myoglobin because they don’t need the extra energy that the mitochondria and myoglobin produces.
The glycogen stores are low along with them having a low resistance to fatigue this is out of the blocks.

Muscle Fibre Types- Slow oxidative
Slow oxidative muscle types are small in diameter, because they only need a small amount of contractile strength and speed. The athletes have trained their muscle to contract enough strength to last them throughout their entire event.
This muscle fibre type has lots of capillaries therefore making the colour of them red, this is because have a high resistance to fatigue because as long as the glycogen and the oxygen are there the body can produce energy.
If he didn’t produce energy aerobically then he would produce more lactic acid, meaning the lactic acid would slow him down and he would not be able to compete as long as he does, he would also be more fatigued earlier due to the lack of oxygen being supplied to the working musclesbecause the energy system only lasts for under 10 seconds, this relates to the fact that the body doesn’t need the glycogen and oxygen to produce energy. These fibres use the ATP-PC