The optimal spring floor for Judo, or What goes under the tatami?

Cool thread!

At the "World's Greatest Camp" in North Carolina and at a couple of judo tournaments I've been to, there were some white mats made out of solid pieces of some kind of foam. it was almost like sheets of insulation that were about an 1 1/2 inches thick. They had them taped together. We did a nage no kata class on one and it was surprisingly good for taking falls. Anyone know what this material is and where to get it? They were really light weight and could be stacked conveniently. It is worth considering for a future project.

GregW wrote:At the "World's Greatest Camp" in North Carolina and at a couple of judo tournaments I've been to, there were some white mats made out of solid pieces of some kind of foam.  it was almost like sheets of insulation that were about an 1 1/2 inches thick.  They had them taped together.  We did a nage no kata class on one and it was surprisingly good for taking falls.  Anyone know what this material is and where to get it?  They were really light weight and could be stacked conveniently.  It is worth considering for a future project.

Ethofoam ... polyethylene foam ... used typically as a packing material inside crates and boxes ... same stuff in the aforementioned foam blocks. Doesn't take traffic well ... over time lose loft. Some of the roll out mats used for events rely on this as the core material ... which is why they are not the best choices for a busy dojo.

Here are some short videos of Judo floors built with foam blocks.

Here is a dance floor built with 3 layers of 2" by 4" boards that were put together in a by crossing the boards in a perpendicular pattern. I wonder if such a construction would work for Judo?

An interesting video on how traditional tatami was made and, used. I wonder if the tatami for homes was the same as used in Judo?

Here is a video several aspects traditional tatami construction. Mostly attaching the cover.

Mr_Michael_or_Mike wrote:I've looked around on the internet and, found many sources for steel coil springs  for industrial purposes. I'm sure someone could figure out which ones might be useful for a floor and, get some brackets to attack to a wood frame. Cover with some Baltic birch plywood, maybe two layers and, purchase some real Japanese tatami. You would have a real Judo floor!

The real Japanese tatami I've done Judo on, even on a sprung floor, were way too hard.

The foam blocks under two layers of plywood, with modern tatami over that, is the way to go.

another thing to consider is that the vast majority of modern dojo in japan now use the ijf style mats, which are not made of the traditional tatami.

good, old fashioned tatami mats cost a hell of a lot, even in japan.

the most comfortable surface i trained on was a dojo that must have had some sort of suspension underneath the hardwood floors. the mats were placed directly on top of the hard wood floors.

worst surface i have trained on was a local town dojo that put gymnastics springs under some plywood boards, which the tatami was laid on top of. it was far too bouncy and very slow. i didnt feel like i could move well on that soft of a surface.

Based on what CK said above, the hard wood floors probably have steel spings underneath. I once stood on what was called a "rolling dance floor" in an old dance hall and, it still had an interesting springy feeling as I walked upon it. It was a solid wood floor. That type of floor would take some sort of skilled construction and, is probably in demand in Japan, but, probably not in the US.

The gym floor springs comment was interesting. I was wondering how that might shape up. One sensei told me he thought the gymnastics spring floor was forgiving, but seemed surprised by the question. I think American Judo coaches take to better floors question the same way they take to new IJF rules; they just adapt.

Here is a Japanese company that sells and ships Japanese made tatami (60mm thick) to the USA. They also sell used tatami that has been used in tournaments.

Tatami of Ooyaseijyou Co,Ltd

I'm looking at upgrading our floor. It's stupidly expensive but I have some ideas.

The Quest for the Perfect Judo Floor
by Paul Nogaki
http://www.judokong.com/2012/08/the-quest-for-perfect-judo-floor.html