PE 34 sac 2 things you got wrong

Using your knowledge of different types of muscle fibre, explain how each of the muscle fibre types might respond to different types of exercise (anaerobic and aerobic).

Type 1 slow-twitch oxidative fibres are best suited to aerobic exercise, since they contain large amounts of myoglobin and large numbers of mitochondria and blood capillaries. They split ATP at a slow rate and have a slow contraction velocity but are very resistant to fatigue. 

Type 2A fast-twitch fibres are also known as intermediate fast-twitch fibres. They can use both aerobic and anaerobic metabolism almost equally to create energy. They have a high capacity for generating ATP by oxidative metabolic processes, and they have a fast contraction velocity, as well as being resistant to fatigue. In this way, they are a combination of type 1 and type 2 muscle fibres. 

Type 2B fast-twitch fibres are best suited to anaerobic exercise. These fibres use anaerobic metabolism to create energy and are the ‘classic’ fast-twitch muscle fibres that excel at producing quick, powerful contractions. These muscle fibres have the highest rate of contraction (rapid firing) of all the muscle fibre types, but they also have a much faster rate of fatigue.

Discuss two differences between the chemical pathways of aerobic and anaerobic glycolysis.

Aerobic glycolysis requires oxygen, whereas anaerobic glycolysis does not require oxygen.

Aerobic glycolysis has the by-products of heat, H₂O and CO₂, whereas anaerobic glycolysis has the by-products of lactate and H⁺ ions.

Outline the advantages and disadvantages associated with the ATP–CP system.

Advantages:

• most rapid rate of supply

• can provide energy for high-intensity activity

• quickly replenishes, enabling repetition of duplicate efforts

• does not rely on energy sources from outside the muscle

• does not rely on oxygen being available.

Disadvantages:

• fuel stores deplete rapidly so can supply energy for only a short time

• requires aerobic conditions to replenish CP stores.

Evaluate the physiological benefits of a passive recovery for an athlete.

• rest recovery allows for faster ATP–PC replenishment

• greater replenishment of ATP–PC stores allows for better performance in subsequent performance

Discuss the role of the skeletal muscle pump in an active recovery.

This is when the muscles continue to contract in an active recovery but at a lower intensity than during the exercise bout. This increases the delivery of oxygenated blood to the muscles and enables the faster return of deoxygenated blood to the heart.

advantages of anaerobic glycolysis

• rapid rate of supply

• predominant energy supplier during high-intensity activity lasting 10–90 seconds

• enables near maximal effort for longer than ATP–CP energy system

• does not rely on oxygen being available

• does not rely on energy sources from outside the muscle

• quick recovery time aided by activity

• lactate can be used as a mobile and rapidly available fuel source.

disadvantages of anaerobic glycolysis

• production of by-products including hydrogen ions, which are implicated as a possible cause of muscle fatigue

• not as quickly available as ATP–CP energy

• does not enable effort for as long as the aerobic energy system

• cannot rely on oxygen being available

• can only use energy sources from within the muscle.