(AP) U.S. and Canadian skiers banging through the slalom gates at the Olympics are benefiting from new fluid armor technology that is also being looked to as a battlefield lifesaver.

Slalom racing suits provided to the U.S. and Canadian Olympic teams by ski wear maker Spyder, for example, contain pads from the British firm, d3o, that contain a fluid that hardens when struck, said Spyder spokeswoman Laura Wisner.

"It just feels like a foam pad, it's not gel, it's not goo, it's like a closed cell foam," Wisner said.

"It's very soft and pliable when you just manipulate it in your hand. However, when you hit it with a hammer or some kind of impact, it instantly becomes hard."

While the first ski suits have already hit the slopes, body armor based on similar technology jointly developed at the University of Delaware and the U.S. Army's Aberdeen Proving Ground is also expected later this year for the military, police and prison markets.

Skateboarding shoes that stiffen when needed are also among the products being developed that use take advantage of so-called shear thickening fluids that harden when a sudden force is applied.

Such fluids can be as simple as a slurry made of corn starch and water. A spoon rested on the surface will slowly sink to the bottom, but if force is suddenly applied the paste can't move to the sides quickly enough and resists.

Boulder, Colorado-based Spyder placed d3o pads on the forearms, elbow and shin areas of the slalom suits it supplied to the U.S. and Canadian teams to protect skiers from collisions with gate markers as they speed down the slopes. Recreational skiers hoping to protect themselves during more mundane collisions will be able to buy suits and shirts containing the pads this fall, Wisner said

In addition to Spyder, d3o has also licensed the material for use by a number of other companies, including RibCap, which makes a flexible helmet for snow sports and the sporting goods firm Sells, which makes soccer goalkeeping equipment.

The military, meanwhile, is looking to improve bullet-proof vests, which are good at stopping projectiles, but not as good at stopping sharp instruments such as an ice pick. Body armor using shear-thickening fluids can also be worn on the legs and arms, providing protection where vest material is too bulky or stiff to function well.

Jacksonville, Florida-based Armor Holdings, Inc. has licensed a technology for coatings developed at the University of Delaware and the U.S. Army's Aberdeen Proving Ground. Armor Holdings does not use pads like d30, but treats ballistic fabric with a shear-thickening fluid.

Although the nano-sized particles used in the coating are suspended in a solution, the fabric does not feel wet to the touch, said Tony Russell, chief technology officer for Armor Holdings.

A variety of materials can be used to create the particles with ceramics and silica most often used, said Norman Wagner, a professor at the University of Delaware who helped develop the solution being used by Armor Holdings.

"Basically it's glass," Wagner said. "You can get materials of remarkably high strength and toughness when you engineer them at the nano scale."

The fabric feels and weighs the same, but when struck the particles lock the fibers of a bulletproof vest into place. That property allows fewer layers to be used to provide the same bullet-proofing protection while also providing stab and fragment protection, he said.

Fabric treated with the fluid also spreads the impact over a larger area, Russell said.

"You're not only trying to stop the bullet but reduce the energy transmitted to the body locally, where the bullet hits," Russell said.

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On the Net:

Spyder: http://www.spyder.com

d3o: http://www.d3olab.com/

Ribcap: http://www.ribcap.com/

Armor Holdings Inc. _ http://www.armorholdings.com

U.S. Army Weapons and Material Research Directorate _

http://www.arl.army.mil/main/main/default.cfm?Action35&Page35

University of Delaware Shear Thickening Fluid site _

http://www.ccm.udel.edu/STF/