The Art of Weight (or Fat)

Sumo... I have always wondered why. Muscle weighs more than fat... so wouldn't it make sense for sumos to get all their weight from muscle instead? That would give them more power too.

Here is my theory: it is for volume and leverage. The way fat is packed on is different from muscle, in distribution. A lot is in the belly, already angled forward, allowing the sumo to use gravity's effect on his weight against the opponent. In the area of volume, it is harder to get your arms around a wide person, and harder to get a grip on something so soft and flabby. The disadvantage to this is that slaps hurt more, which is why the sumos are always slapping each other.

What makes me doubt the validity of this pro-fat training (even though sumo do have incredible strength) is that Chiyonofuji, a champion Yokozuna and one of the best sumo ever, was very small and had incredible musculature and low fat and low body weight compared to most other sumo. So I think there is validity in his style of training, so why isn't it used? Must sumos be fat to fit a stereotypical cultural image?

I'm thinking a 300lb bodybuilder versus a 300lb sumo of equal height and body type (sans fat) and equal sumo and grappling training would be interesting.

I think you're thinking along the right lines. Muscle is denser than fat but the distribution is very different. Many sumou wrestlers have a lot of muscle but are covered in a whole lot of fat, too. I once saw a TV show in Japan that was comparing the average fat boy to a sumou wrestler of seemingly equal build. the sumou wrestler had a much larger percentage of muscle (I don't remember the actual percentages). Having a larger mass makes it harder for someone else to change your momentum, therefore making it more difficult for someone to move you some place you don't want to go. However, sumou wrestling, like judo, has a lot to do with throwing someone off balance by using their own momentum. In this way, someone with good reflexes who is quick on their feet will have a marked advantage in this respect.

As for your last comment, I saw a clip of a muscular maybe 200+ pound guy against a 400+ lb fat boy in a UFC event. The muscular guy kept trying stuff like grabbing the fat boy and punching him, but the fat boy just stood there and laughed because he didn't even feel the attacks through his fat. But eventually, the muscular guy literally climbed on the back of the fat boy and did repeated double-handed hammer blows to the base of the fat boy's skull until he gave up. The fat guy had a large amount of neck fat too, so it wasn't lethal or anything, but it took him out.

The idea, I believe, is that since such a large portion of their training is spar wrestling, the fat acts as a training weight they never take off. Now, if you have 100lb of training weight.. dunno, I'm probably the last person who should post on this thread, ha!

- Op. Skinny Ninja