30-year-old Thomas -- 6'3", 212 lbs. -- flexed (literally) on Instagram on Monday, deadlifting 530 lbs. for one rep using a trap bar ... and doing it with what looked like relative ease.

It probably shouldn't come as a shock ... Thomas is one of the world's most elite athletes. Prior to being drafted in 2016, Michael put up 18 reps of 225 lbs. ... better than three-fourths of the other athletes at the wide receiver position.

Thomas played in only three games in the 2022 season ... after missing all of the 2021 campaign. In 2020, MT played in 7 games. But, prior to 2020, Thomas was arguably the best wideout in the game. He caught 149 passes in 2019, scoring 9 touchdowns.

FYI, the deadlift world record is held by Hafthor Björnsson -- aka "The Mountain" -- who pulled an absurd 1,105 lbs. in May 2020. But, Thor weighed around 450 lbs. ... so, Thomas' lift is damn impressive!