Question

Regarding the make-up of a person's muscle fiber ratio, which of the following is correct?

1) Type I muscle fibers are also known as slow-twitch fibers and are used for endurance activities.
2) Type II muscle fibers are also known as fast-twitch fibers and are used for explosive activities.
3) The muscle fiber ratio in a person's body is determined by genetics and cannot be changed through exercise.
4) A person with a higher percentage of Type I muscle fibers is more likely to excel in powerlifting.

Answer 1

Slow-twitch fibers are used for endurance activities, while fast-twitch fibers are used for explosive activities. The muscle fiber ratio is determined by genetics but can be influenced by exercise. Individuals with a higher percentage of Type II muscle fibers may excel in powerlifting.

Step-by-step explanation:

Skeletal muscle fibers can be divided into two types: slow-twitch (or type I) muscle fibers and fast-twitch (or type II) muscle fibers. Slow-twitch fibers are known as endurance fibers and are used for activities that require sustained aerobic activity, such as long-distance running. Fast-twitch fibers, on the other hand, are known as power fibers and are used for explosive activities like sprinting or weightlifting.

The muscle fiber ratio in a person's body is determined by genetics, but it can also be influenced to some extent by exercise. While you cannot change the proportion of muscle fiber types, you can train and improve the function of both types through targeted exercise. However, individuals with a higher percentage of Type II muscle fibers (fast-twitch fibers) may have a greater advantage in activities that require power and strength, such as powerlifting.