Right from childhood, I've always wondered why marathon runners are extremely skinny and haggard with little or no muscle. In fact, most of them look very weak and healthy unlike 100m, 200m and 400m runners

Please don't get me wrong! I'm not trying to say that ALL marathon runners are looking haggard and skinny but most of them really are. I know there are still some professionals marathon runners out there who aren't looking skinny and haggard as you may assert

Most marathon runners I've seen participating in Olympics are extremely skinny and bony looking like they will die tomorrow but that doesn't necessarily mean they are not healthy or are weak

From my own little understanding, I think the whole idea of a professional marathon runner looking so thin, unfit and haggard is because of the way they're trained to sustain endurance during their training, which is to keep their body and weight from increasing, because muscle carries a lot of calories per day and as a marathon runner it will be too much of a load.

On the other side, there are still a lot of people who can run quickly with a lot of muscles, especially if you're the type that is supremely filled with a well-developed running technique, but as a professional marathon runner you don't need muscles at all.

The optimum amount of muscle is very small for marathon runners and that's why the type of training they undergo eats up their muscle so that they can go on a lengthy race.

Most marathon runners are not unhealthy as they look and from my little research I discovered they are only looking haggard and bonny so that

1. Their bones and skeleton will be extremely strong because bones normally adapt to stress and pressure and their entire skeleton gets hours of pounding every day

2. Their muscles will be incredibly fit and their resting heart rate will be incredibly low

3. Most professional haggard looking marathon runners have nutritionists taking care of their diets for them so that they will not develop heart problem

What's your take on why professional marathon runners always look haggard and unhealthy?