LeBron James Gets In 5 AM Shirtless Workout After Vacay, Message To Haters?!?

LeBron James appears to be sending a message to his haters who think he isn't working hard this offseason ... by posting videos of him hitting the gym shirtless at 5 AM!

James threw up the clips on his Instagram on Wednesday morning ... showing that despite being on a few vacays the last several weeks, the Akron native is still getting after it, and is still completely jacked.

James captioned one of the videos at 5 AM by writing, "The perfect place to pull up on to relieve so stress! Time to work."

He then showed off his chiseled shoulders, chest and abs while getting in some kettlebell and cable work.

Of course, the timing of the posts is interesting ... LBJ's been under a lot of scrutiny lately from fans who believe he's been enjoying his offseason just a little too much after the Lakers' disappointing season.

Bron's been spotted vacationing in the Maldives with his wife, Savannah, as well as in Miami ... where he partied his face off for the F1's Grand Prix event.

So, were these vids a clap back at the haters?!?