TMZ Sports has obtained insane footage of ex-NFL quarterback Marcus Vick -- Michael Vick's brother -- literally running from cops during an incident back in April ... before being captured at gunpoint.
It all started at a gym in Newport News, Virginia -- when cops were questioning the 32-year-old about a warrant out for his arrest stemming from a civil case.
Vick spoke with cops for nearly 10 minutes before suddenly deciding to make a run for it -- shoving 2 cops out of the way, breaking tackles -- and SPRINTING down the street.
Cops gave chase ... but Vick is WAYYYYYYY FASTER (he ran a 4.42 in the 40 at the 2006 NFL Combine).
It seemed like he was going to get away -- but the cops stayed with him, and Vick eventually tired out ... sat down on the ground and gave himself up.
But when the trailing officer caught up to Vick -- he drew his weapon, pointed it at the seated Vick and ordered him to show his hands and get on his stomach.
The whole thing is pretty intense ... but Vick is eventually taken into custody without further incident.
He was later convicted of resisting arrest and sentenced to a year in jail with 11 months suspended. He also got 12 months probation.
By the way, at the end the video you can hear one of the cops say ... "If he ran I knew we weren't gonna catch him."