# Fartlek Interval Trainer vs Unit One Gym Training

The clearest difference is in-app purchases: Unit One Gym Training at none against Fartlek Interval Trainer's 4. Unit One Gym Training also leads on device support (4 vs 2) and iOS requirement (15.5 vs 26.0). On price, update cadence and ads there is nothing between them.

Both are free to download. Fartlek Interval Trainer sells 4 in-app purchases, starting at $0.99 per month. Unit One Gym Training asks for nothing beyond the download.

Fartlek Interval Trainer ships an update every 9 days, Unit One Gym Training every 2 weeks. The most recent releases landed on October 24, 2026 and October 17, 2026 respectively.

## The numbers

| Metric | Fartlek Interval Trainer | Unit One Gym Training |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 9 days** | Every 2 weeks |
| Monetization | Freemium | — |
| Size | 86 MB | 198 MB |
| Requires iOS | 26.0 | **15.5** |
| Devices | iPhone, Apple Watch | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [Richard English](https://appshunter.io/developer/1537547687) | [UNIT ONE GYM (GUISELEY) LTD](https://appshunter.io/developer/1800480837) |

## What reviewers say

### Fartlek Interval Trainer

[App page](https://appshunter.io/ios/app/fartlek-interval-trainer/id1537547685)

This running app automatically detects spontaneous intervals during Fartlek runs, providing live color-coded feedback on your effort. It also functions as a powerful timer for structured workouts like HIIT and Tabata, offering detailed metrics and syncing with Strava and Apple Health.

**Highlights:** Auto-detection of Fartlek intervals, Live color-coded effort feedback, Structured workout timer (HIIT, Tabata), Detailed interval metrics, Strava and Apple Health integration, Advanced effort level detection

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $0.99 | per month |
| Annual | $6.99 | per year |
| RemoveAds | $0.99 | one-time |
| Lifetime | $14.99 | one-time |


### Unit One Gym Training

[App page](https://appshunter.io/ios/app/unit-one-gym-training/id6761938862)

**Features:** Apple Wallet, Apple Watch app

**In-app purchases:** none


## Frequently asked questions

### Is Fartlek Interval Trainer free?

Fartlek Interval Trainer is free to download, with in-app purchases available.

### Is Unit One Gym Training free?

Unit One Gym Training is free to download, with no in-app purchases.

### Do Fartlek Interval Trainer or Unit One Gym Training have ads?

Neither Fartlek Interval Trainer nor Unit One Gym Training shows ads.

### Which is updated more often, Fartlek Interval Trainer or Unit One Gym Training?

Fartlek Interval Trainer ships an update every 9 days, and Unit One Gym Training every 2 weeks. Most recently, Fartlek Interval Trainer was updated on October 24, 2026 and Unit One Gym Training on October 17, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*