# FLEX Stronger vs Proteus Motion

The clearest difference is review sentiment: FLEX Stronger at 71% against Proteus Motion's 0%. FLEX Stronger also leads on rating (4.4 vs 3.0) and update cadence (monthly vs every 6 months). On price, ads, in-app purchases and monetization model there is nothing between them.

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

FLEX Stronger holds the better App Store score, 4.4 against 3.0. Both are backed by a comparable volume of ratings — 8 and 2 respectively. Written reviews point the same way: 71% of FLEX Stronger's written reviews are positive against 0% of Proteus Motion's.

FLEX Stronger ships an update monthly, Proteus Motion every 6 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

## The numbers

| Metric | FLEX Stronger | Proteus Motion |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (8 ratings)](https://appshunter.io/ios/app/flex-stronger/id1452436164/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/proteus-motion/id1540100362/reviews) |
| Number of ratings | **8** | 2 |
| Positive reviews | **71.4% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Monthly** | Every 6 months |
| Monetization | Free | Free |
| Size | 56 MB | 38 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Kinetic Performance](https://appshunter.io/developer/343232407) | [Proteus Motion Inc.](https://appshunter.io/developer/1540100364) |

## 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


### Proteus Motion

[App page](https://appshunter.io/ios/app/proteus-motion/id1540100362)

This app provides advanced performance training and recovery analytics. It enables low-impact, high-efficiency 3D resistance training. A Proteus System user account is required to use the app.

**Highlights:** Performance training analytics, Recovery analytics, 3D resistance training, High efficiency training, Low-impact training

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is FLEX Stronger free?

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

### Is Proteus Motion free?

Proteus Motion is free to download, with no in-app purchases.

### Which has better reviews, FLEX Stronger or Proteus Motion?

FLEX Stronger is rated higher. FLEX Stronger averages 4.4 out of 5 from 8 ratings, while Proteus Motion averages 3.0 from 2 ratings.

### Do FLEX Stronger or Proteus Motion have ads?

Neither FLEX Stronger nor Proteus Motion shows ads.

### Which is updated more often, FLEX Stronger or Proteus Motion?

FLEX Stronger ships an update monthly, and Proteus Motion every 6 months. Most recently, FLEX Stronger was updated on November 2, 2026 and Proteus Motion on November 3, 2026.

---

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