In part 13 Sarah Palmer is watching a black and white boxing fight on her TV.
The KO is a loop on the screen.
Finally, someone have found who were the fighters : Matt Marrone in the last edition of Blue Rose Magazine
(a very long and hard investigation)
It was on february 4th 1935 in New York for the "Golden Gloves".
The winner is Stephen Rozakis and the guy on the floor was Michael Juppe.
Both were novices.
At 1'45" on this video you can watch the part of the fight seen in Twin Peaks.
No sound on the video, the sound was added for Twin Peaks and was not original.
That was a fine piece of detective work on the part of the Blue Rose staff. I quite enjoyed reading that entire article!!
A visual/televised reminder of the state of Sarah's mind. Naturally, the fighter in black shorts defeats the man in white repeatedly on a constant loop, showing the destruction of Sarah's 'inner light' at the hands of her shadow self.