Isaiah Pead Crushes 1st Track Workout With Prosthetic Leg

This is amazing ... ex-NFL running back Isaiah Pead hit the track in Oklahoma for his first running workout with his prosthetic leg -- AND HE KILLED IT!!

The 28-year-old lost most of his left leg in a Nov. 2016 car accident -- but he finally got a running prosthesis and on Monday afternoon, he decided to test it out.

You gotta watch the video ... Pead is nothing short of impressive.

Remember, Pead only got the new leg on Friday and could barely walk in it at first. Just a few days later he's running windsprints.

Yeah, he fell down during one of the drills (adjusting to a prosthetic leg ain't easy) -- but he got right back up and continued the drill.

We spoke with Pead who tells us it was great to get out there and run again. He acknowledged learning how to run with the new leg is challenging, but he's up to the task.

Pead previously told TMZ Sports his goal is to compete in the Paralympics and win some gold medals -- looks like he's off to a good start.