Jugglers don't focus on any 1 particular ball; they use this type of vision to keep track of the whole area
Even before the student picks up any balls, the preliminary lesson is to... [DOC] [TLE] juggle - Twirl Mania [PAR] Using a table has two advantages: it means you don't have to stoop as far to pick 
up ... learn good habits by confining your juggling to a more-or-less fixed area.