Sprint start reaction
World Athletics rules treat any reaction under 0.100 seconds as a false start, on the reasoning that a human cannot hear the gun and respond faster than that, so anything quicker was anticipation. Elite sprinters typically come out between 0.12 and 0.16 seconds. The threshold has been criticised because some athletes have demonstrated genuine responses slightly under it in the laboratory, but it remains the rule and it is enforced by force sensors in the blocks rather than by the starter's eye.
The numbers
- Typical
- 140 ms
- Range
- 120 ms to 180 ms
- What it is
- Reaction — a decision, via the brain
- What is measured
- Time from the gun to measurable force change in the starting blocks.
Why this is a reaction
A reaction is a decision: signal in, processing, movement out. The floor for a human is around 150 milliseconds, and anything measured below about 100 ms is anticipation rather than response.
Where it sits against everything else
Reflexes at the top, reactions in the middle, design values off the end of the scale.
Sport
| What | Typical | Range | Kind |
|---|---|---|---|
| Time a jab takes to land | 110 ms | 80 ms–150 ms | Physical limit |
| Formula One start reaction | 200 ms | 150 ms–300 ms | Reaction |
| Time to hit a 95 mph fastball | 400 ms | 375 ms–425 ms | Physical limit |
| Time a goalkeeper has on a penalty | 450 ms | 400 ms–600 ms | Physical limit |
| Time to play a 90 mph delivery | 500 ms | 450 ms–550 ms | Physical limit |
Common questions
- How long is sprint start reaction?
- Typically 140 ms, with a real range of 120 ms to 180 ms. Time from the gun to measurable force change in the starting blocks.
- Is that a reflex or a reaction?
- Reaction — a decision, via the brain. A reaction is a decision: signal in, processing, movement out. The floor for a human is around 150 milliseconds, and anything measured below about 100 ms is anticipation rather than response.
Related pages
- Time a jab takes to land 110 ms
- Formula One start reaction 200 ms
- Time to hit a 95 mph fastball 400 ms
- Time a goalkeeper has on a penalty 450 ms
- Time to play a 90 mph delivery 500 ms
- A reflex is not a reaction Why one is 20 ms and the other 250
- Stopping distance at every speed Reaction distance plus braking distance, computed
- Measure your own reaction time Five attempts, median reported
Sources
- Typical range compiled from manufacturer specifications — At One Place