Final answer:
Olympic marathon runners have a higher proportion of slow-twitch muscle fibers in their legs compared to Olympic weightlifters. Slow-twitch muscle fibers are more suited for endurance activities and can sustain aerobic activity for longer periods.
Step-by-step explanation:
The skeletal muscle fibers in the legs of an Olympic marathon runner differ from those of an Olympic weightlifter in terms of the proportion of slow-twitch (SO) and fast-twitch (FO and FG) muscle fibers.
Marathon runners have a larger proportion of slow-twitch muscle fibers compared to weightlifters. Slow-twitch muscle fibers are more suited for endurance activities, like long-distance running, as they have more capillaries, mitochondria, and myoglobin which enables them to carry more oxygen and sustain aerobic activity for a longer period of time.
Weightlifters, on the other hand, have a greater proportion of fast-twitch muscle fibers which are better suited for explosive movements and high-intensity activities.