2014 Chicago Marathon to guarantee spots for some runners

Some big changes are coming to this year's Chicago Marathon. Runners will be guaranteed spots in the race, but only if they have participated in a marathon within the past two years and under certain conditions.

Men must have completed a marathon in less than 3 hours and 15 minutes. Women must have finished in less than 3 hours and 45 minutes. A lottery will be held for non-guaranteed spots.

Registration for the marathon begins March 5.