The Zapruder film indicates no such thing.
“To this day, millions remain unaware that such forthright evidence of a second gunman was undermined almost from the beginning. In 1965, researchers using a frame-by-frame comparison discovered the head went violently forward between Zapruder frames 312 (last frame before impact) and frame 313 (head explosion). The subsequent backward motion is much more slower and thus more distinctive in live-action viewing.”
http://mcadams.posc.mu.edu/organ2.htm
Now we’re getting to distortions! A golden oldie too, the mother of all conspiracy red herrings.
I guess you’ve never watched the Zapruder film. People who deny the implications of Kennedy being forced”back and to the left” are like liberals who, on issue after issue, eg gender, insist that people not trust their native common sene and their own eyes, but must have it explained away by sociological gibberish