Question

What was the most dangerous greek sport

Answer 1

At first I thought it was the "Olympics" I used to study Greek history but I'm sure Chariot racing and "heavy events" like boxing (yes they did wrestle) Anything involving "violence" is considered dangerous. 

Answer 2

I would say that Chariot racing would be the most dangerous, chariot wheels could lock together and there were many crashes.
Hope this helped :)