Also, just as today "tapping out" signifies a concession as does shouting out "Uncle!", back in the heyday of catch wrestling rolling to one's back could also signify defeat, as it would mean a pin. Catch-as-catch-can toeholds typically only exert force if the opponent sits still; therefore, Frank Gotch won many matches by forcing his opponent to roll over onto their back with the threat of his signature toehold. A "hook" can be defined as an undefined move that stretches, spreads or compresses any joint or limb. Therefore, another name for a catch wrestler was a "hooker," with the similar term "shooter" being relegated to specially skilled hookers. Catch wrestling techniques may include, but are not limited to: the arm bar, Japanese arm bar, straight arm bar, hammerlock, bar hammerlock, wrist lock, top wrist lock, double wrist lock (this hold is also known as the Kimura in MMA, or the reverse Ude-Garami in judo), head scissors, body scissors, chest lock, abdominal lock, abdominal stretch, leg lock, knee bar, ankle lock, heel hook, toe hold, half Nelson, full Nelson and almost infinitely many others. Nowadays many of such novel techniques came from cross cultural exchanges with judo and jujutsu proponents. Almost all moves have their own variations and different predicaments they can be pulled off in. The rules of catch wrestling would change from venue to venue. Matches contested with side-bets at the coal mines or logging camps favoured submission wins where there was absolutely no doubt as to who the winner was. Meanwhile, professionally booked matches and amateur contests favoured pins that catered to the broader and more gentle paying fan-base. The impact of catch wrestling on modern-day amateur wrestling is also well established. In the film "Catch: The Hold Not Taken", US Olympic Gold Medalist Dan Gable talks of how when he learned to wrestle as an amateur the style was known locally, in Waterloo, Iowa, as catch-as-catch-can. The wrestling tradition of Iowa is rooted in catch wrestling as Farmer Burns and his student Frank Gotch are known as the grandfathers of wrestling in Iowa. A notable match in 1914 was between two prime representatives of their respective crafts: the American catch wrestler Ad Santel was the World Light Heavyweight Champion in catch wrestling, while Tokugoro Ito, a 5th degree black belt in judo, claimed to be the World Judo Champion.