Out On One's Feet Meaning

Example : 1998 April 30, Bob Sculley, "Physician Deplores Medical Indifference To America's," Ludington Daily News (retrieved 18 May 2013):  Such schedules frequently leave them ragged and unrested. "How good is it for a patient to be treated by an intern who is almost out on his feet?" she asked.2000 Nov. 16, Bill Pennington, "Pro Football: Toomer's Concussion Now a Scary Memory," New York Times (retrieved 18 May 2013):  But several of his teammates later said Toomer was jabbering nonsensically in the huddle and seemed out on his feet.2011 April 8 "Cowdenbeath FC's victory thrills Raith Rovers boss John McGlynn," The Courier (UK) (retrieved 18 May 2013):  We had so many games to cram in such a short space of time, it really stretched our squad and the lads were out on their feet.1945 April 9, "Puffy, The Hypnotizing Cat, Named Honorary Feline Society President," St. Petersburg Times, p. 5 (retrieved 10 May 2013):  "Well sir, that girl was simply out on her feet. It wasn't from drinking, either. I'm something of a hypnotist myself and I quickly realized that she was in a real hypnotic trance, brought on by Puffy's staring into her eyes."1955 August 31, "Merchants Form Plan To Aid Small Business: Will help those hit by floods," The Hartford Courant, p. 1 (retrieved 18 May 2013):  According to Savitt there are many such small concerns who are out on their feet, and still in a state of shock.1968 March 23, John Bird, "The new PM: tired before he starts," Financial Post (Canada), p. 32 (retrieved 10 May 2013):  The new leader who will be elected on April 6, becoming Prime Minister shortly thereafter, is likely to be very nearly out on his feet.