Warning: At these Olympics, sprinters will get no warnings.
Under the zero-tolerance false-start rule in place for the London Games, a sprinter's mistimed jump from the blocks could destroy four years of hard work in an instant. If that runner happens to be, say, Usain Bolt, it could turn one of the most anticipated moments of the entire Olympics into one huge downer.
Under the old rule, the entire field was given a warning after the first false start and the disqualifications began with the second one. Under the new rule, the first person to jump is out - no second chances.
The new rule goes on display on the sport's biggest stage Friday when the women line up for the 100-meter heats. Bolt, seeking back-to-back titles in the marquee race of the Olympics, hits the track Saturday.
''A double-edged sword,'' 2004 Olympic champion Justin Gatlin calls the new rule, which took effect in 2010. ''Because some people can take advantage of it if it's two or three false starts and no one i...