I like the piston analogy - it's a vivid comparison of the two types of motion. The piston's physically connected to the crankshaft, so its straight-line motion precisely mirrors the rotating crankshaft's motion along that same axis. The crankshaft never stops moving, so the piston must not either.Fran, regarding your juggling analogy earlier, maybe a closer analogy would be the motion of a piston in an engine. The cylinder end moves back and forth like the cue tip, while the other end is attached to a crankshaft and moves in a circular motion, as the elbow would in a stroke where the elbow doesn't experience a start/stop type motion.
It's a natural trigger at exactly the right time and place for one - it triggers greater all around focus for me. I'm sure it's programmable to some degree.I have found that the pause triggers me to think about relaxing those muscles completely just before the forward stroke begins.
pj
chgo