One phone. An audio start cue. Practice-grade reaction only. Prop the phone still, settle into set, and leave when SpeedTrackr plays on your mark, set, gun. No coach, no starter, no partner.
This is not official starting blocks, not splits, and not form AI. There is no native iOS App Store app. Android package com.speedtrackr.reactionpro: Google Play. Same trainer on the web at speedtrackr.com/auth/login. Keep the number next to start and finish timing, jump, and phone VBT. Coach Mode is on the web app and the Android app.
Dedicated reaction apps are fine when that is the whole job. SpeedTrackr's wedge is solo practice reaction inside the session lab: start/finish timing, jump/RSI, phone VBT, and Coach Mode names on every rep.
Practice grade. Not federation approved meet timing. No invented competitor accuracy numbers. Free to start on Google Play, or open the web app after sign-in.
Prop one phone still where you can hear the audio start cue. This is practice, not official starting blocks.
On your mark. Get into set. Stay still until the start signal. Stillness is part of the practice.
The app plays the audio start cue: on your mark, set, then the gun. React to that sound. No starter or partner required.
You get a reaction time you can write down and beat next week. Run more reps between full timing sessions.
One phone, no starter. The trainer runs the same way on the web app and the Android app.
01
Put the phone on a tripod or lean it against a bag or wall, 1 to 2 m away, so your head, shoulders and both wrists are in view. Never hold it. The camera reads a shaking phone as movement.
02
The gap between set and the gun is the same every time, not random, so it can be learned. React to the sound, not the rhythm. On the web app you can change the set to go delay between attempts.
03
One rep is noise. Run 5 to 10 attempts, leave out false starts, and take the median yourself: sort the times and pick the middle one. The session summary shows your average and best.
04
Play the start cue through the phone speaker or wired earphones, not Bluetooth. Bluetooth adds a delay before the gun reaches your ears, so every time reads slow.
05
The clock starts at the gun and stops at the first movement the camera sees at your hands. Moving before the gun is a false start. There is no sensor in the blocks.
This is a training estimate, not official block reaction time. The 0.100 s false start rule applies only to starting blocks with sensors.
Runs on the web app and Android: Google Play or speedtrackr.com/auth/login.
General coaching cues for the ritual. Not medical advice. Not a performance guarantee. Just how to treat a phone session like a real start.
01
Find a stable set you can hold. Hands and feet where you would start a race. Quiet the fidget before the cue.
02
Prop the phone still. Stay still yourself. Shake and early movement turn practice into noise.
03
Wait for the in-app start cue. Leave on the gun, not on a guess. False-start tension is the point of the drill.
04
Use Reaction Timer as the practice ritual between full start/finish timing sessions. Same athlete. Same honesty.
Quotable answers for measuring sprint start reaction time alone: solo setup, scope vs SprintStart/BlockLaunch, starter needs, iPhone vs Android, and how reaction differs from full sprint timing.
One phone. Audio start cue. Practice-grade reaction only. Free to start on Android, or open the web app.
A lightweight browser session for a quick reaction check on this page. This is the same Reaction trainer the signed-in web app opens, so iPhone users can run it in the browser. Sign in on the web app or get the Android app to save reps under athlete names.
Visual Stimulus & Neural Response Timing