John is a sprinter who specializes in quick and powerful bursts of speed followed by periods of rest.Jim is a marathon runner who specializes in long,steady runs.Compared to John,Jim is likely to have

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Marathon runners like Jim rely on aerobic metabolism to produce energy for prolonged periods of exercise, so they need a lot of mitochondria in their type I and II a muscle fibers. Myoglobin is an oxygen-binding protein that helps transport oxygen to muscles during aerobic exercise, so Jim is also likely to have more myoglobin in his type II b muscle fibers to support sustained activity. However, glycogen is primarily used during anaerobic (without oxygen) metabolism, which is not as important for marathon running, so Jim may not have more stored glycogen in his muscle fibers compared to John, a sprinter who relies heavily on anaerobic metabolism.

John Is a Sprinter Who Specializes in Quick and Powerful