Sprint Start Trainer vs NinjaButton
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Sprint Start Trainer
This app helps athletes practice sprint and swimming starts by measuring reaction time and reviewing technique using video. It offers various start signal sounds and timing modes to simulate real race conditions, turning your phone into a portable training tool.
- Video reaction time measurement
- Technique review
- Customizable start signal sounds
- Fixed and randomized interval modes
- Manual cue control
- Automatic repeat starts
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Practice track sprint and swimming starts with just one phone. Starter Kit is a start-training app for sprinters, swimmers, and coaches. It does more than play start signals: it lets you measure reaction time on video and review start technique. In Timing and Random modes, each video frame displays the time relative to the moment the start sound plays, with that moment set to zero. Read the displayed time on the frame where the athlete first moves to measure reaction time, then review technique in the same video. With fixed or randomized signal intervals, you can practice track block starts and swimming dive starts on your own or with a team. WHO IS IT FOR? • 100 m and 200 m sprinters • Track athletes who want to practice block starts • Swimmers who want to practice dive starts and improve their response to the start signal • Track-and-field coaches and swimming coaches running start drills • Athletes who want to improve reaction time and start technique KEY FEATURES ■ Video reaction-time measurement and technique review In Timing and Random modes, Starter Kit adds a timer to every video frame, using the start signal as zero. Read the value displayed on the frame showing the athlete's first visible movement to measure reaction time and review start technique. Videos can be saved to Photos, and recording can continue for up to 90 seconds after the start sound finishes. With up to 90 seconds of recording, you can also use the on-video timer to measure an accurate start-to-finish time. ■ Three start signal sounds Choose a pistol sound, swimming start beep, or electronic start sound to match your sport or training session. The swimming beep makes Starter Kit useful for swimming start practice as well as track sprint starts. ■ Timing mode: fixed intervals Set the timing between “On your marks,” “Set,” and the start signal. Repeat the same start sequence for individual or team practice. ■ Random mode: randomized intervals Randomize the intervals between “On your marks,” “Set,” and the start signal. The timing varies within your chosen range so athletes can practice reacting without anticipating the signal. ■ Manual mode: individual cues Play “On your marks,” “Set,” and the start signal separately. Use it for coach-led or group drills, or play the swimming start beep on its own at the pool. ■ Automatic repeat starts In Timing and Random modes, run start sequences repeatedly at an adjustable interval for efficient practice sets. Starter Kit turns your phone into a portable start-training tool for the track or poolside—no dedicated starting system required. Automatic repeat starts and custom recording durations require an upgrade.
NinjaButton
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NinjaButton is a wireless button for timing sports activities with your smartphone. Place NinjaButtons at the start, finish, or other points on your course, and simply press a button to control the stopwatch on your smartphone. You can register up to three NinjaButtons with the app. ■ Registering a NinjaButton 1. Open the app and tap the gear icon in the upper-right corner to open Settings. 2. Tap “QR CODE” and scan the QR code on your NinjaButton. 3. Confirm that the Button ID appears, then tap “APPLY.” 4. When “READY” appears on the main screen, you’re ready to start timing. You can also register a NinjaButton by entering its Button ID manually. ■ Timing 1. Make sure “READY” is displayed on the main screen. 2. Press a registered NinjaButton to start the timer. 3. Press a NinjaButton again to stop the timer and display the result. 4. Tap “RESET” to clear the result and get ready for the next measurement. If multiple NinjaButtons are registered, you can control the stopwatch from any of them. ■ Main Features ・Wireless timing with NinjaButton ・Register up to three NinjaButtons ・Easy Button ID registration by QR code ・Manual Button ID entry ・Time display to 1/100 of a second ※A NinjaButton device, sold separately, is required for wireless timing with this app.
Screenshots
Verdict
The clearest difference is in-app purchases: NinjaButton at none against Sprint Start Trainer's 1. NinjaButton also leads on ads (none vs shown) and iOS requirement (15.5 vs 18.0). On price and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Sprint Start Trainer sells 1 one-off in-app purchase. NinjaButton asks for nothing beyond the download.
| Parameter | Sprint Start Trainer | NinjaButton |
|---|---|---|
| Price | Free | Free |
| Rating | 4.9 (16 ratings) — better | — |
| Positive reviews | 90.0% of reviews | — |
| Number of ratings | 16 — better | — |
| Update frequency | Every 3 weeks | — |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone | iPhone, iPod — better |
| Requires iOS | 18.0 | 15.5 — better |
| Further details — not scored | ||
| Size | 29 MB | 38 MB |
| Age rating | 4+ | 4+ |
| Developer | Koki Osada | CONCEPT PROTO Inc. |
In-app purchases
Sprint Start Trainer
- Premium Upgrade$4.99
NinjaButton
No in-app purchases
Questions
Is Sprint Start Trainer free?
Is NinjaButton free?
Do Sprint Start Trainer or NinjaButton have ads?
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