Up And At 'Em Meaning

(idiomatic, hyphenated when used attributively) Vigorously launched or launching into an activity.

Example: 1945 Nov. 12, "Sport: Stretch Drive," Time (retrieved 29 May 2015):
  At 41, Jockey Richards was still up and at 'em last week, and his wrists and knees were still persuasive enough to boot home the winner in Newmarket's Icklingham Stakes.
2002 Sep. 15, Simon Schama, "A Whiff of Dread for the Land of Hope," New York Times (retrieved 29 May 2015):
  [O]nly two alternative responses seem available: irrepressible up-and-at-'em chirpiness or apocalyptic hysteria.
2011 Sep. 9, Andrea Sachs, "Bed Check: Mountain dreamin’ in W. Va.," Washington Post (retrieved 29 May 2015):
  I padded downstairs to find everyone up and at 'em, their day leaps ahead of mine.
2013 Nov. 18, Stephen Brenkley, "Peter Siddle hungry to leave some banana skins in England's path," Independent (UK) (retrieved 29 May 2015):
  Siddle is the sort of up-and-at-'em, tearaway fast bowler whom you imagine to train on raw red meat while running over a bed of hot coals.