Muscle Fiber Quiz

The muscles of a professional sprinter are most likely to have ________.

• 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers

• 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers

• 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers

• 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers

The muscles of a professional marathon runner are most likely to have ________.

• 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers

• 40 percent fast-twitch muscle fibers and 60 percent slow-twitch muscle fibers

• 50 percent fast-twitch muscle fibers and 50 percent slow-twitch muscle fibers

• 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers

Which of the following statements is true?

• Fast fibers have many mitochondria.

• Fast fibers have large glycogen reserves.

• Fast fibers have a small diameter.

• Fast fibers contain loosely packed myofibrils

Which of the following statements is false?

• Slow fibers contain a large number of mitochondria.

• Slow fibers have a small network of capillaries.

• Slow fibers contract for extended periods

• Slow fibers contain the pigment myoglobin

What changes occur at the cellular level in response to endurance training?

What changes occur at the cellular level in response to resistance training?