Question

Physiology of Exercise

11. An elite powerlifter would most likely have a higher percentage of which fiber type?

12. Explain blood glucose homeostasis during exercise. Talk about the hormone involved and the actions they take to control our blood glucose.

13. How do athlete's differ from the general population in hormone and receptor number.

14. What are some of the common fare markers (fats & triglycerides) that are seen in a blood test and what do they mean and how can someone change those levels.

Answer 1

An elite powerlifter would most likely have a higher percentage of type IIa fibre (Fast twich) type.

explanation:

Muscles are made up of multiple motor units. Each one contains a bundle of nerves and fibers. Muscle fibers are classified into 2 types. i.e slow twitch(ST) or fast twitch(FT), depending on how quickly they produce tension in a muscle.

Slow twitch muscle fibers are known as type I fibers, and the name describes the fact that they contract slowly and steadily. These fibers are recruited for endurance and lower-intensity activities.

Fast twitch muscle fibers are known as type II fibres.It also  contract quickly and more powerfully. They are needed for high-intensity but short-duration activities, like sprinting or lifting a really heavy weight. They contract quickly and fatigue quickly.

FT muscle is again of 2 types. i.e. type II a and type II x.

Type I Muscle Fibers

These are the slow twitch muscle fibers. They are smaller than type II fibers, are slower to produce tension, and they produce less force and power.

They are used for endurance activities, and endurance athletes tend to have a higher proportion of these muscle fibers. Long-distance runners, triathletes, and distance swimmers.

Type IIa Muscle Fibers

Type IIa muscle fibers are fast twitch, meaning they fire more quickly. They are also more powerful than type I fibers and are recruited for activities that require more intensity: sprinting, lifting heavy weights.

Strength and power athletes, like sprinters and weightlifters, have higher proportions of type IIa fibers in their muscles.

Type IIx Muscle Fibers

There is a second type of fast twitch muscle fiber called type IIx. These are even faster and more powerful than type IIa. They are also even more inefficient, fatiguing very quickly. Type IIx fibers are used for activities of very short duration that require significant power and strength.

For power lifting, a quick , strong contraction is required.and training FT muscle fibres and anaerobic energy source is essential.

Here, FT muscle fibre produce a rapid and large force. because:

• they have a high capability for transmitting an electrical signal.
• their cross bridges work faster
• there is a rapid release and use of calcium in the muscle.