Tony Hawk -- who suffered a career-threatening broken femur just last week -- is already up and walking without crutches ... further proving the skateboarding legend is simply built different.
The 53-year-old posted the update on Thursday ... showing a slow and steady walking pace with only a slight hobble.
It's pure insanity -- given how gnarly the break was -- but it shouldn't come as a surprise ... after all, Hawk was putting weight on the busted leg just one day after his skating accident.
Tony seems to be having some fun during his recovery .