Genuine question is he rapid or are people just assuming he is?
I don't think he is "rapid", from what I have seen, Oli Burke is rapid.
For Jebbo, he has great stride length, so he covers a lot of ground fairly quickly, without much effort.
I only notice this, because I used to go jogging with my lad, and he was also shooting off ahead of me, so I said once, "I know you are quicker than me, and so you should be at your age, no need to show off" and he said "Dad, I'm not running fast?", and when I looked closely, he wasn't, but at 6ft 4 inches, his stride length was much bigger than mine, even though I am 6ft 2. I think Jebbo is the same.