SwimStart: Reaction Trainer

The race is decided before you touch the water. Rehearse the start off the blocks, measure the gap between signal and push-off. Apple Watch too. No ads.

The race is decided before you touch the water. SwimStart is a start-reaction trainer for swimmers: rehearse the start off the blocks, measure how long it takes you to move after the signal, and drive that number down.

A REAL START SEQUENCE • A countdown, then the "Take your marks" call, then the start tone • The hold after the call is randomised, so you cannot memorise the timing • Reaction time is measured on a monotonic clock, so your numbers compare fairly • Move too early and it is flagged as a false start — exactly like at a meet

TRACK YOUR PROGRESS • Every attempt is saved with its date, reaction time and false-start flag • See your best time, your average and how many false starts you had • Your full attempt history in one list

SET IT UP YOUR WAY • Turn the spoken "Take your marks" cue on or off • Set the countdown length and the range of the wait before the signal • Choose touch or motion: tap the screen, or leave the device on a stand and move it

ALSO ON APPLE WATCH • A standalone Apple Watch app — leave the phone in your bag • Practice, records and settings straight from your wrist • A haptic cue alongside the sound, which helps at a noisy poolside

SIMPLE AND PRIVATE No account, no sign-up. Your records stay on your device.

SwimStart is a training aid. It measures your reaction to a signal from your phone or watch and does not replace official starting equipment or a competition timing system.