It works by implanting wireless sensors into the chest protector, or "hogu".

CNN: High-tech blow for martial arts

Familiar with Unequal's claims that its pads can absorb up to 80% of the "chronic impact shock" from hits, Mr. Hatfield asked Unequal to design a chest protector for Mr. Vick using the same patented technology Unequal develops for shoes worn by some NFL players.

WSJ: Michael Vick's Endorsement of Unequal Technologies Padding