The Ultimate Guide to Judo tatamis
There is no one solution to prevent injuries from critical heights in martial arts, but one of the best things that you can do is to get the right foam mat underneath to dissipate the kinetic energy that a falling athlete produces. It’s always better to be proactive than reactive, and by researching types of foam mats you’ve taken that first step to plan to protect your athletes.
Flexible polyurethane (PU) is one of the most versatile materials ever created, and its prized specifically for its shock absorbing properties. PU foam is ubiquitous, and likely you might have used a product that has polyurethane foam in it recently: car cushions, furniture padding, carpet cushions, electrical insulation, and foam packaging. It’s a perfect material for trapping in warm air and insulating a house. In fact, 1.6cm thick polyurethane insulation has the same insulation efficiency as a 1.34m thick concrete wall1.
An open-celled, durable foam, polyurethane easily absorbs and redirects the kinetic energy from falls. What makes PU foam so good at absorbing shocks is that it is open-celled, meaning that in each centimeter of foam there are hundreds of small air pockets open to the outside environment. These cells fill with air, and when a critical fall occurs, the athlete lands in a pocket of air and they’re cushioned from potential injury. Immediately after the pressure has been lifted off of it, polyurethane foam fills again with air.
Let’s dig a little bit more into polyurethane foam to discover if its a perfect fit for your gym.
Polyurethane Foam Production
Polyurethane foam has been in use since the 1930s after being invented by Otto Bayer. Polyurethane foam is produced from a reaction of two key elements: a polycol and an isocynate with water2. Shortly after the reaction, a foaming reaction begins, and carbon dioxide bubbles begin to form throughout the foam mixture. In many ways, it’s like a loaf of bread rising.
In just a few minutes the reaction is complete.
The most common way of producing polyurethane foam is the slab-stock method, whereby the foaming reaction occurs instantly on a large conveyor belt, creating a continuous slab of foam. These large slabs resemble loafs of bread 1.2 meters high. After the forming process, the slabs are carved up into the proper size for the foam.
Reconstituted (Chip Foam) Polyurethane Foam Production
Unlike most synthetic products, every last scrap of polyurethane foam is used to produce reconstituted polyurethane foam. Let’s continue with the loaf of bread metaphor: The tiny scraps of polyurethane foam are collected, shredded into tiny pieces, and then compacted and bonded together to form high-density chip foam. The end result is an extremely resilient and firm product.
This is an environmentally friendly way to produce foam mats because the scraps aren’t tossed in a bin, but are used to create a new product. In some ways, as a result of the high pressure and heat bonding which occurs, chip foam is a superior product to simple polyurethane foam. Seldom does the recycling process create a product of superior quality, but in the case of reconstituted PU foam it’s the case.
This product is a high-density foam unlike any of PU foam you’ll come across. It possesses this unique fusion of cushioning ability and shock absorption because of the crucible with which polyurethane foam is produced. Chip foam is able to breathe, capture air, and create that perfect air cushion underneath athletes, but it’s also able to be firm enough to get a good grip.
When athletes grapple, traction is incredibly important to getting the upper hand in a match. Too much cushioning can greatly inhibit an athlete’s ability to have a firm footing. Chip foam is a densely compacted foam.
Density of Reconstituted Polyurethane Foam
It’s important to know that density doesn’t determine firmness, but instead is an industry standard for durability, an indicator of how long a mat will hold up. Density is measured in kilogram per cubic meter (kg/cbm). Density is an indicator of rigidity, how a mat will bounce back after compression, and typically higher density foam will retain its original properties and provide support and comfort it was originally designed to do.
Reconstituted PU has a much higher density than other foams, especially original PU foam. Most PU foams are of medium density (30kg/cbm – 50kg/cbm), whilst other closed cell foams like EVA and XPE are high density (over 50kg/cbm). At British Martial Arts Mats, we offer a Judo mat with a chip foam core that has a density of 230kg/cbm. This chip foam core has higher resilience than 90% of foam mats on the market and will stand the regular wear and tear of regular use. Compared to EVA jigsaw mats, the PU chip foam Judo flooring tile is a much denser mat. Even the EVA mats that we offer have a density of 100kg/cbm.
Cushioning Ability of PU compared to EVA and XPE
There are some great mats out there which are made with ethylene-vinyl acetate (EVA) and cross-linked polyethylene (XPE). These types of mats are closed-cell foams, in which all the air pockets created during the foaming process are self-contained entities. These foams don’t allow for the transfer of air in and out of these pockets, and therefore are much firmer.
PU is an open-celled foam, with all the pockets open for air to travel in and out. The benefit of PU chip foam is that due to compression it has higher firmness than regular PU foam, but it still allows for the transfer of gasses. This means that a fall from 1.5m, the critical fall height, will be a little softer with our Judo mat.
Other Features of the Judo tatami Mats
The outer coating of the Judo flooring is a PVC foam which is formed into a tatami coating. This tatami coating adds much needed grip, allowing an athlete to make explosive movements and change directions on the fly. Paired with the high-density chip foam, you’ve got an innovative injury prevention system when you purchase the Judo gym mats from British Martial Arts Mats.
Some other features of the Judo tatami are the latex waffle pattern base, which is the perfect anti-slip base. As well, each of the corners are heat welded together, which seals the PVC and creates a durable outer layer that is not easily pierced.
The 1mx1mx 40mm Judo mat, made from a reconstituted PU chip foam, is the perfect mat to protect against falls. This mat comes in especially handy when you’re training new students and they’re more likely to fall. It can also be used when learning advanced skills which may put combatants in danger of falls from critical heights (1.5m).
Conclusion
Polyurethane mats are extremely handy to have in a Martial Arts Gym, and have become the industry standard for thick crash mats. Reconstituted chip foam carries the same shock absorbing properties, with a density that outmatches EVA and XPE foam mats. Durable and able to outlast other mats on the market, consider picking up the Judo tatami mat from British Martial Arts Mats with stand up to the regular wear and tear of competitive combat sports, and allow the athletes to have the best traction to perform complex maneuvers.
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Author: David Van Kooten
1.https://www.polyurethanes.org/en/what-is-it/
2.https://www.pfa.org/wp-content/uploads/2021/02/InTouch1.1.pdf