If you're running in this year's marathon, heed this warning to keep your time down and your run at 26.2 miles. According to the Chicago Sun-Times:
"Attention Bank of America Chicago Marathon runners who signed up to run 26.2 miles and not a step further: Take tight turns.
Runners who don’t hug the 36 turns along the marathon route could unwittingly add up to a half mile to their race, resulting in unwanted extra minutes to their finishing time, according to rough calculations by Jay Wight, who measures Chicago’s course for USA Track and Field and, for the first time Friday, put some thought into the matter.
“Over a course that long, with that many turns, if you’re not running the tightest line, you’re going to be adding significant distance,” said Wight."