It's even true in prison

Up The River (1938) is a great old movie starring Preston Foster and the incomparable Arthur Treacher and a sterling cast of character actors. Early in the film, as Treacher and Foster return back to prison after being pinched once again for pulling bunko tricks, Slim Summerville, the coach of the prison football team, comments, "You read about them high-powered coaches, but I've coached at Atlanta, Levenworth and Sing-Sing, and a coach is no better than his material."