Final answer:
A person with a high percentage of fast-twitch muscle fibers excels in sports requiring quick bursts of power like sprinting and weightlifting. Fast-twitch fibers are crucial for activities involving strength and speed. Professional sprinters typically have around 80% fast-twitch fibers, whereas marathon runners have a higher percentage of slow-twitch fibers for endurance.
Step-by-step explanation:
A person with a high percentage of fast-twitch muscle fibers would be best suited for sports that require short bursts of power and speed, such as sprinting or weightlifting. These muscle fibers are primarily responsible for anaerobic activities, which do not require oxygen but provide quick energy for high-intensity movements. Fast-twitch muscle fibers contribute significantly to muscle strength and bulk, making them essential for activities that involve explosive power, jumping, and throwing.
For a professional sprinter, the muscles are most likely to contain about 80 percent fast-twitch muscle fibers and 20 percent slow-twitch muscle fibers, as indicated by Choice A. In contrast, a professional marathon runner would likely have the opposite composition, with about 20 percent fast-twitch muscle fibers and 80 percent slow-twitch muscle fibers, as shown in Choice B, given their need for endurance and sustained aerobic activity.