Light travels much faster than sound, which theoretically ensures that the propagation speed does not have a disproportionate impact on the athletes. But not only the running events did not use the light countdown, but swimming also still use the whistle.

One of the reasons is to prevent athletes from false start. Because when they see “1” or hear “1”, they will subconsciously feel that they are about to start, and may rushing out before hearing “GO” , so the probability of false start is higher.

In the Olympic Games before 2012, starting pistols are still used. In 2012, the electronic trigger gun became the standard for the Olympic Games.

When the trigger is pulled, the electronic starter “gun” does three things at once: the light flashes, the pulse is sent to the electronic starter, and a recording of the gunshot is played.

The signal from the starting gun is transmitted to the loudspeaker on the athlete’s starter. Then a sound similar to a gun is emitted. This is designed to avoid the signal being propagated through the speed of sound, causing runners who are far away to receive the signal later than those who are closer. The speed of sound is a seemingly insignificant difference in everyday life, but it is magnified in sporting events. At the Sydney Olympics, Michael Johnson heard the signal much later because he was on track 9. His reaction time was 440ms, while the average athlete’s reaction time was about 140ms, which is equivalent to the gun being 0.5 seconds late.

At the same time, it also could a false start detection system, so if the runner starts within 100 milliseconds of the signal, the system will be judged as a false start, which is the minimum reaction time set by the IAAF.

However, this does not mean that only the gun or whistle is used as the starting signal for running or swimming events.

For example, some deaf runners are unable to hear the signals transmitted through sound. So there are signals similar to those used in racing
A small box similar to a traffic light is placed on the ground in front of the runners’ starting positions, and this visual signal helps these runners to receive the signal accurately. The amber light comes on, and the red light goes off when the “Ready” is given, and the green light comes on, and the amber light goes off when the “Run” command is given.

Similarly, there is a similar visual way to transmit signals to deaf swimmers. The light stick shown in the picture glows red when the starter gives the command “On your mark,” blue when “Ready,” and green when “Start ” will emit green light.