Just after contacting the cue ball (near address position) and the 90° myth is exploded! Rather, the forearm is seen moving toward the target, as in most stick and ball games requiring a throw motion.
The laws of physics dictate that the cue tip compresses from impact with the ball for micro-fractions of a second before moving forward a second time, and the cue's motion may slow, but the subjective feel of the stroke is one of lightly swinging back then throwing “through” the cue ball in one flowing, uninterrupted motion.
