Robert Griffin III's Wife Training For 2020 Olympics, She's Faster Than Me!

Robert Griffin III says his wife wears the (track) pants in their relationship ... 'cause Grete Šadeiko is not only making a run at the 2020 Olympics -- she blows him away in races!!

We got the adorable couple -- and their cute 1-year-old baby, Gloria -- out in Bev Hills when RGIII made the revelation to TMZ Sports.

"Track is her realm," he says. "She owns the track."

Big-time praise for sure ... considering the NFL star once ran a 4.38 40-yard dash and did do some track events at Baylor.

But Grete's legit on the turf ... she crushed the heptathlon at Florida State -- once running 13.92 in the 100-meter hurdles -- and is making a serious run to compete for Estonia in the 2020 Games.