The 100-meter sprint is the shortest race in most track & field competitions. Races are won and lost based on how fast a runner starts, wind conditions and other factors that are crucial because every millisecond counts. While the rules of the 100M dash seem fairly straightforward, there are a few regulations that runners must follow to avoid disqualification.
The 100M sprint (or 100M dash) takes place on the straightaway of a track. From start to finish, the 100M sprint is a total distance of 100 meters (109.36 yards). The racer that reaches the finish line in the shortest amount of time wins. In general, if more than eight runners participate in a race, qualifying heats are run with the eight fastest runners advancing to the finals. Different organizations may vary the maximum amount of runners allowed in each heat and the number of "rounds" until the finals.
Lanes and Equipment
Before each 100M race heat, runners will learn in which lane they will run. Runners must remain in their assigned lane for the entire race. If a runner crosses into another runner's lane and is caught, officials will disqualify him from the race. Runners may not obstruct other runners' paths with any parts of their bodies.
Runners wear special shoes with short spikes that must not exceed 9mm (.35 inches). At the start of the race, runners crouch and place their feet on devices known as starter blocks. Once in the ready position, runners must keep their feet on the blocks until the starter's gun goes off.
Starting On Time
100M sprints begin when the starter fires a starter pistol that sets off the automatic timers. If a runner starts before the pistol, it is a false start and the race is halted and re-started. Although the International Association of Athletics Federations proposed instant disqualifications for false starts in 2008, as of 2009 runners are still allowed a warning "false start." Upon the second false start, a runner is disqualified. False starts are measured by apparatuses in the runner's starting blocks. If pressure is released from the blocks too early, a false start is charged.
Time is kept with automatic scoring clocks. A runner finishes the race only after his trunk crosses the finish line. For this reason, 100M sprinters often lean forward at the finish of the race. To ensure the most accurate placings, a digital line-scan camera will remain focused on the finish line. Linked to the overall timing system, these cameras are highly accurate and can differentiate between thousandths of seconds.