In order to ingrain onto the neuron paths in the brain a particular way of doing something that is not covered by any of the automatic responses, you do need to do that action repeatedly... I doubt very much if it is 20,000 times though....
Sports people, actors, dancers etc often use the technique of *thinking through* a particular problem or new action (like learning a new dance routine or gymnastic display) by simply going through the new action step by step in their head.... learning takes place when new connections are made between brain nerve cells..... and these connections can be made even if one is not actually physically going through the routine. Anyone who has learned his or her multiplication tables by rote will still be able to recite these donkeys years later without any real calculation or memory skills.