The name is from Theodore Roosevelt.
On April 23, 1910, the year after his presidency ended, Roosevelt stood at the Sorbonne in Paris and gave a speech to a French audience that has been remembered, for over a century, by exactly one passage. It is the passage every founder eventually finds. It is the passage every kid who builds something hard eventually needs.
"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood; who strives valiantly; who errs, who comes short again and again, because there is no effort without error and shortcoming; but who does actually strive to do the deeds; who knows great enthusiasms, the great devotions; who spends himself in a worthy cause; who at the best knows in the end the triumph of high achievement, and who at the worst, if he fails, at least fails while daring greatly."
Theodore Roosevelt · "Citizenship in a Republic" · Sorbonne, Paris · April 23, 1910
School today rewards the critic. The kid who points out how the answer could have been better. The kid who reads what was assigned and returns what was expected. Arena exists for the other kid. The one in the arena, with the dust and the sweat and the wrong first draft. The one who, when school says that's not what we're learning this week, builds it anyway.