ON Wednesday morning, a short man walked up to a huge steel light pole in Riverbank State Park in Harlem and began punching away at it.

The logo on the back of his warm-up jacket — “Johnny Knuckles, the Italian Steel Puncher” — suggested that this was not his first time doing this. So did the two discolored spots on the pole where the man’s fists were pounding, as well as the man’s taut physique and his toughened fists, enlarged with calluses.

His punches started out as firm rhythmic thuds, each blow causing a dull clang that resonated up the steel column. But they got quicker and harder until this featherweight was grimacing as his roundhouse rights slammed into the steel. Passers-by shook their heads, the skies darkened, but the man only shed his jacket and kept slamming the steel in the rain.

“I call it my art,” said the man, Johnny DeVincenzo, 77, a Brooklyn native who is 5 feet 2 inches tall. “It makes me feel elevated.”