The Packers’ Cecil Isbell was one of pro football’s best passers in the prewar years. He set several short-lived NFL records in his career (1938-42) — for passing yards in a game (333) and touchdown passes (24) and passing yards (2,021) in a season, among others — and might be in the Hall of Fame if he hadn’t retired at 27 to go into coaching.
And he did all this despite wearing a chain — secured by a harness — that ran from his waist to his upper left (non-throwing) arm, limiting the range of motion and keeping the shoulder from popping out of the socket. He’d suffered a bad separation in college and was worried it might happen again.
A cartoonist’s rendering of Isbell’s unusual piece of equipment: