Forget plyometrics, Tom Brady‘s clearly hitting the weights in retirement … check out his arms following his latest gym session Wednesday — dude’s biceps are bulging!!!

TB12 got in the sweat sesh down in Miami on his off day from his Fox broadcasting duties … and it’s clear it was an upper-body hump day for the GOAT.

Take a look at what was underneath the sleeves of his tan shirt as he walked out of the fitness facility … his pythons were hissin’!

Of course, we’ve known for a while now Brady’s been improving his body drastically following the end of his football days … as he’s been seen topless and chiseled a whole lot over the last year or two.

Still, the images from his post-workout glow Wednesday are hard to ignore … considering he was known for having such a soft and pliable bod during all his years with the Patriots.

It’s unlikely we’ll see more of Tom’s physique over the next few days … but you can catch his face and his vocal cords on a TV this weekend — as he’s slated to call the big Cardinals vs. 49ers game in Santa Clara on Sunday.