Ex-Big Brother Star -- TROLLS CROSSFIT ... After 41 Street Pull-Ups

Former "Big Brother" star Jessie Godderz -- now one of the biggest wrestlers in TNA -- busted out 41 meatheaded pull-ups on an NYC traffic light IN A ROW ... and TMZ Sports has the footage.

Mr. Pec-tacular was just looking for a reason to take his shirt off ... when he suddenly came up with the challenge for himself.

We also asked him about Prince Fielder posing for ESPN's Body Issue -- but who cares, watching this guy do 41 pull-ups ... and then troll the cross-fit people ... is pretty entertaining.