# FLEX Stronger vs Train.Red APP

The clearest difference is rating: Train.Red APP at 5.0 against FLEX Stronger's 4.4. FLEX Stronger's advantage is ratings volume (8 vs 1). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Train.Red APP holds the better App Store score, 5.0 against 4.4. That said, the two scores are not equally well evidenced: FLEX Stronger has 8 ratings behind it against 1, so its average is the more settled of the two.

FLEX Stronger ships an update monthly, Train.Red APP every 3 weeks. The most recent releases landed on August 6, 2026 and July 30, 2026 respectively.

## The numbers

| Metric | FLEX Stronger | Train.Red APP |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.4 (8 ratings)](https://appshunter.io/ios/app/flex-stronger/id1452436164/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/trainred-app/id6451237438/reviews)** |
| Number of ratings | **8** | 1 |
| Positive reviews | 71.4% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Monthly | **Every 3 weeks** |
| Monetization | Free | Free |
| Size | 83 MB | 101 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Kinetic Performance](https://appshunter.io/developer/343232407) | [Train.Red B.V.](https://appshunter.io/developer/1646391181) |

## What reviewers say

### FLEX Stronger

[App page](https://appshunter.io/ios/app/flex-stronger/id1452436164)

This app revolutionizes weight training by syncing with a sensor to provide real-time performance feedback. Track, manage, and review your training like elite athletes, with automated workouts and group training options. It offers detailed metrics, video recording with data overlay, and a community feature for sharing and downloading workouts.

**Highlights:** Real-time performance feedback, Velocity-based training (VBT), Automated workouts, Group training for up to three people, Video recording with synced data, 1RM prediction, Workout creation and sharing

**Features:** macOS Compatibility

**In-app purchases:** none


### Train.Red APP

[App page](https://appshunter.io/ios/app/trainred-app/id6451237438)

This app monitors muscle oxygen saturation to provide real-time physiological insights for athletes and coaches. It helps optimize performance, track recovery, and analyze training data with actionable metrics.

**Highlights:** Muscle oxygen saturation monitoring, Real-time physiological insights, Performance and recovery tracking, Workout analysis and data export, Team/organization structure, Live data overlay

**In-app purchases:** none


## Frequently asked questions

### Is FLEX Stronger free?

FLEX Stronger is free to download, with no in-app purchases.

### Is Train.Red APP free?

Train.Red APP is free to download, with no in-app purchases.

### Which has better reviews, FLEX Stronger or Train.Red APP?

Train.Red APP is rated higher. FLEX Stronger averages 4.4 out of 5 from 8 ratings, while Train.Red APP averages 5.0 from 1 ratings.

### Do FLEX Stronger or Train.Red APP have ads?

Neither FLEX Stronger nor Train.Red APP shows ads.

### Which is updated more often, FLEX Stronger or Train.Red APP?

FLEX Stronger ships an update monthly, and Train.Red APP every 3 weeks. Most recently, FLEX Stronger was updated on August 6, 2026 and Train.Red APP on July 30, 2026.

---

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