Everyone knows that the Roman emperor decided whether a fallen gladiator should die by giving a thumbs down or up to the other gladiator holding a sword at his opponent's neck, right? And those people who are actually interested in gladiators know that before the fight the gladiators addressed the emperor to say "Morituri te salutant" 'Those who are about to die salute you'.
The trouble is these aren't facts at all.
It appears that the blame for these urban legends can partly be laid at the brush of one talented and popular artist, Jean-Léon Gérôme (French, 1824-1904), as Bingley points out in a forum thread on Morituri Te Salutant.

Comments
Those crazy neoclassical idealists…
How can “better muscled” be discerned on skeletons? Or was flesh preserved?
John – I changed the original post. I can’t get to the article I thought I paraphrased to verify. Other articles refer to the corpses as robust. I believe heavy exercise, which results in heavy musculature, translates into stronger or bigger bones, so although muscle may be a stretch, I don’t know if it’s much.
At John Kerr: I fell hard on concrete and broke my arm in 2006. My orthopedic surgeon was showing me the x-rays of my arm when I asked about old age and bone loss. He looked at the x-ray and looked at me, then he asked: “Were you a weight lifter?”
Yep – I was: between ages 13 and 18. It was over 40 years later and this doctor could still immediately detect the evidence of my above average “robust” body. So there’s no reason to doubt the report about gladiators’ bones showing evidence of heavier than average musculature.
Oh, BTW – I recovered 100% from the bone fracture: something the orthopedic surgeon says “never happens.” This is just the “dividend” I got from all that weight lifting and shot putting I did as a teen.