Kevin Hart's strong.
Check out this footage of the funnyman busting his ass in a Miami gym Sunday morning with Dolphins superstar Ndamukong Suh ... pulling the 320-pounder in a sled LIKE A BOSS!!!
Hart -- who's a hardcore gym rat -- wrote, "Listen up people ... Its not about the size of a man its about the size of the "Hart" within the man!!!! I refuse to be outworked."
He added some pretty hilarious hashtags -- #KickingMyBodiesAss #iPulledTheS***OutOfHisBigAss #ImAbeastDamnIt #BossNeedsToWipeThatDumbassLookOffHisFace #SuhWasGrowlingAtMeWhileIwasPulling."