# Redline: Sprint Timer — Sprint Intervals for Runners

> Sprint Intervals for Runners (iPhone/iPad app by STEPHEN MARK SCHLESINGER.)

- Source: https://appshunter.io/ios/app/redline-sprint-timer/id6807452754 (this page in markdown: same URL + `.md`)
- Developer: [STEPHEN MARK SCHLESINGER](https://appshunter.io/developer/6791812406)
- Category: Health & Fitness, Sports
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: American English
- Released: 2026-09-05
- Data updated: 2026-09-05
- User reviews in markdown: https://appshunter.io/ios/app/redline-sprint-timer/id6807452754/reviews.md

## What is Redline?

Six sprints. Thirty seconds each. All out.

Redline is a timer for sprint interval training, and nothing else. No account, no login, no feed, no subscription. You set the number of sprints, press start, and put the phone in your hand.

HOW IT WORKS

Ten seconds to get to the line. Thirty seconds flat out. Then rest until you are genuinely recovered, and go again. Six repeats is the number most people settle on, but you can run anywhere from one to ten, with one to ten minutes of rest between them.

IT TALKS TO YOU

Voice cues call every transition, so you never have to look at the screen while you are running. Ten seconds. Go. Stop. Recover, three minutes.

The cues play over whatever you are already listening to. Start Spotify, Apple Music or a podcast first, and Redline ducks it for a second and then gets out of the way. There is nothing to connect and nothing to authorize. It keeps talking with the screen off and the phone in your hand.

ON YOUR WRIST

The Apple Watch app runs the whole session on its own, with your phone left in the car. Every transition is a tap on your wrist, so you can run this with no headphones at all and still know exactly when to go. Your setup and your history stay in step across both devices.

ON YOUR LOCK SCREEN

A Live Activity shows the current sprint and the time remaining on your Lock Screen and in the Dynamic Island. Glance at it in the middle of a rest without unlocking anything.

SAVED TO HEALTH

Every finished session is written to Apple Health as a high intensity interval workout, so it counts toward your rings. Redline also keeps a simple history and a day streak on your device. There is no account to create, because there is no account.

WHY THERE IS NO SKIP BUTTON

The rest is the training. Thirty seconds is about as long as anyone can hold a genuinely all-out effort before power falls off a cliff, and the sixth sprint only counts if you are actually recovered when you start it. Skipping the rest turns sprint intervals into a jog with extra steps.

Redline is a timer, not medical advice. All-out sprinting is strenuous. Warm up properly first, and talk to a doctor before you start if you have any reason to.

Free. No ads. No subscription. No tracking.


## Version history (last 1 release)

### 1.0 — 2026-09-05

No release notes.

## More apps by STEPHEN MARK SCHLESINGER

- [GrillMaster: BBQ Grill Timer](https://appshunter.io/ios/app/grillmaster-bbq-grill-timer/id6791812404)
- [The Examined Day](https://appshunter.io/ios/app/the-examined-day/id6792599813)

All apps by STEPHEN MARK SCHLESINGER: https://appshunter.io/developer/6791812406

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-05.*