But you have to be able to -- in case you are thrown in the [metaphorical] deep end! The gym part was used by Jack Black in School of Rock -- but I think it came from Woody Allen originally: “Those who can't do, teach. And those who can't teach, teach gym.”

So again [metaphorically, on the Road partaken] if you can't do you have to be able to teach gym [metaphorically] and LOL -- tongue in cheek

-- because I find it so funny -- Jack Black at his best is a scream!