There is a concise statement of effective practice to achieve mastery in the video of the 1st link you listed (which is a TED talk), from 2:04 to 2:32 in the video; and tips for practicing from 3:05 to 3:54.
Regarding "muscle memory" -- check out this Psychology Today article: www.psychologytoday.com/us/blog/the-athletes-way/201503/how-does-practice-hardwire-long-term-muscle-memory which mentions an interesting fact: "The optokinetic reflex [OKR] is a combination of a saccade and smooth pursuit movements of the eye. The OKR is seen when an individual follows a moving object like a tennis ball with his or her eyes. When the object moves out of the field of vision, the reflexive response is for the eye to move back to the position it was in when it first saw the object. This reflex typically develops at about 6 months of age." The OKR might be a big part of the impulse to look up as you make ball contact (at which time "... the object moves out of the field of vision..."; requiring a big effort to "keep your head down" after ball contact.
