Punch sounds are always added after filming, of course, because the actors aren’t really hitting each other. Early filmmakers felt that the genuine sound of a fist hitting a face was too dull to match its visual excitement. So sound professionals invented more thrilling, phony punch sounds to dub in—audio effects that came to be known in the trade as “the Hollywood punch” or the “John Wayne chin sock.” Hams were slapped, belts whipped. In an old Western, an outlaw getting slugged might be accompanied by a recording of billiard balls clacking. For kung fu movies, bamboo stalks were whacked on boards.
"The sound of a punch that we’re familiar with is not made with any punching. It’s a wet towel slapping on a wall, sometimes with a pencil breaking added in there," says Leslie Shatz, who worked on "Out of the Furnace."
As film sound became more sophisticated, and movie budgets rose, professionals moved away from using libraries of canned sounds, cooking up different audio effects for every punch using fresh ingredients. “Raging Bull,” Martin Scorsese’s 1980 biopic of volatile boxer Jake LaMotta, was a sonic boom. The late Frank Warner, sound effects supervisor for that film, mixed into fight scenes a stew of recorded sounds that included animal roars and metallic clinks. He famously never revealed his exact audio formula.
Soon creative acts of violence against beef, pork, poultry, fruits and vegetables became common.
I’m pretty sure “hams were slapped” is the best phrase I have read in 2014 so far.