In sprinting, a starter uses 3 commands:

• On " Your Mark"
• "Set"
• the sound of a starting gun

A false start occurs if a racer starts before the gun is fired, and results in disqualification of the athlete. This discourages anticipation and forces athletes to react. The time between when the runner's body senses the gun and when they actually act is called "reaction time".

Different people have different reactions times. What would make one person have a different reaction time than another? Does a person respond better with one sense than with another? Do the conditions surrounding the reaction make a difference?

One way to test your reaction time and observe the affect of different stimuli is to see how quickly your can grasp a falling ruler. Go to "Investigating the Question" to see how.