Reaction time is a scoreboard number, not a talent

The figure printed beside a sprinter's name measures a pressure sensor's patience more than an athlete's nervous system.

A reaction of nought point one four appears on the screen and the commentary treats it as a character reference. Sharp. Alert. Ready. It is nothing of the sort.

What the timing system detects is force on the block pedals exceeding a threshold. The clock stops when the athlete pushes hard enough, and how quickly they reach that force depends on how they are set, how much force they can produce, and how tense they were holding the position. Two athletes with identical nervous systems will show different figures because one of them sits with more pre-tension in the legs. The number is a mixture of physiology and setup, reported as though it were pure physiology.

Then there is the floor. Anything under a hundredth is ruled a false start on the assumption that no human can respond faster, a rule that is more convention than measurement, and it means the entire distribution of reported reactions is squashed against an arbitrary line. Athletes know it. Some of them shade their anticipation right up to it, which is not reacting at all, it is guessing well.

None of which means the start does not matter. It means the number does not describe what people think it describes, and the training implication follows. Drilling responses to a gun improves the figure a little at the start of a training age and then stops improving it, because the trainable part is small. Meanwhile the athlete's ability to convert that response into speed, which is force and position, has a much larger range and gets ignored because it does not have its own column on the results sheet.

If you want to change the number honestly, get the athlete stronger and get their set position right so that force arrives at the pedal sooner. That is the same work that makes the first thirty metres better. Two birds.

If you want to change the number dishonestly, teach them to anticipate. Plenty do, quietly, and the sport has decided to police it with a rule about a hundredth of a second rather than admit the measurement was always approximate.

I would print it in smaller type than the finishing time. It is a footnote pretending to be a headline.