Why do marathon runners look so skinny

Install and read again anytime! Sign in Get started Get started. Fantasy Sports. Extreme Sports. Horse Racing. Ice Hockey. Am Football. Martial Arts. Figure Skating. Field Hockey. Professional marathon runners are also skinny because they train so hard to sustain endurance. This prevents their bodies from bulking up because they burn almost all the calories that they consume.

The difference between long-distance runners and short-distance runners is their body mass. Unlike marathon runners who are light and skinny, short distance runners are a bit bulky. This is because they run for short distances hence need a bulky body to give them the much need power to sprint. On the other hand, marathon runners mainly depend endurance. More capillaries mean more oxygen and nutrient delivery for your improved power plants.

As your muscles budget less energy for maintaining mass, the fast-twitch fibers in your endurance-trained muscles begin to shrink; at the same time, your slow-twitch fibers do get bigger, but not enough to offset the loss of fast-twitch size. In this battle between fast-twitch atrophy shrinkage and slow-twitch hypertrophy growth , atrophy wins, resulting in smaller, more physiologically-efficient muscles.

Then again, you may not want to sacrifice a stronger build for a slightly faster time in your next 5K or marathon. Never fear. High-intensity training e. As long as the high-intensity training is separated from the endurance stimulus e.