Under Armour will debut its latest piece of technology – the E39 – at the NFL Scouting Combine. The 4.5 oz chest button measures acceleration, heart rate, horsepower, and other stats that seem important.

What does the thing actually do?

“What we have is something very close to the body’s center of mass that’s measuring the accelerometry data from that center of mass,” Under Armour vice president Kevin Haley told Wired.com.

Oh, right.

One number not measured: Under Armour’s stock price – up 152 percent year over year – which will only continue to climb.

(H/t Darren Rovell)