New rate-dependent straps aim to protect heads in NFL

New rate-dependent straps developed by the U.S. Army Research Laboratory aim to decrease likelihood of head injuries during tackles and heavy hits in the National Football League. Nathan Frandino reports.

WASHINGTON, D.C., UNITED STATES (REUTERS / U.S. ARMY RESEARCH LABORATORY) – What looks like a small paintbrush could actually be a savior for future players in the National Football League.

This new technology is no brush though.

Dr. Eric Wetzel and his team designed it at the U.S. Army Research Laboratory.


“We call is a Rate Actuated Strap, or RAT Strap. It’s this elastic material that has this very special property that if you pull slowly on it, it’s easy to stretch and it relaxes again, but if I jerk it quickly, it resists with much more force. In fact, it’s about 100 times more force to pull it quickly than to pull it slowly.”

The RAT Strap was created with football players in mind.

It was developed in the Head Health Challenge II; a joint initiative by the NFL, sportswear makers Under Armour and General Electric.

The initiative’s goal is to create new technologies to better protect players from head injuries.

Wetzel says the strap was designed to slow a player’s head from slamming into the ground when tackled.


“So we envisioned integrating these straps with the head system so that before the head strikes the ground, the straps will slow down that head motion, sort of like a shock absorber, so the head will strike the ground with less velocity, less force, that should be less force on the brain and be less likely to cause a brain injury.”

This slow motion video shows the head without the strap getting hit and being pushed farther from its normal position.

Here, after being hit, the head with the strap is kept closer to its normal position.

Wetzel says the elastic strap contains something called a sheared thickening fluid.


“That’s a liquid that has a weird property that if you flow it slowly, it has a low viscosity but if you try to flow it quickly, it transforms into a solid-like material that resists flow, very similar to concentrated corn starch in water, which sometimes kids make in science class.”

And whether it’s in science class or on the football field, it’s a product that the NFL hopes will keep its players safer.