Question

Resistance training results in a ______.

a. Slow-to-fast shift in μscle fiber types
b. Fast-to-slow shift in μscle fiber types
c. None of the above are correct
d. Decrease in the number of slow μscle fibers

Answer 1

Resistance training does not result in a fast-to-slow shift in muscle fiber types. Instead, it increases the proportion of fast-twitch fibers and leads to hypertrophy, or the enlargement of muscles, due to an increase in myofibrils and muscle fiber thickness.

Step-by-step explanation:

Resistance training results in a fast-to-slow shift in muscle fiber types is not a correct statement. What actually happens is that resistance exercise affects muscles by increasing the formation of myofibrils, which leads to an increase in the thickness of muscle fibers. This added structure causes hypertrophy, or enlargement of muscles, which is often exemplified by the large skeletal muscles seen in bodybuilders and athletes. Resistance training typically increases the proportion of fast-twitch fibers (FG fibers) relative to slow-twitch fibers (SO/FO fibers) because it involves powerful, short bursts of movement that are not repeated over long periods, as opposed to endurance exercise which can lead to enhancements in slow-twitch fibers. Muscles used for power, therefore, have a higher ratio of fast-twitch fibers, which are essential for strong muscle contractions.