# FLEX Stronger — Velocity-based Training (VBT)

> Velocity-based training app with real-time feedback and performance tracking. (iPhone/iPad app by Kinetic Performance.)

- Source: https://appshunter.io/ios/app/flex-stronger/id1452436164 (this page in markdown: same URL + `.md`)
- Developer: [Kinetic Performance](https://appshunter.io/developer/343232407)
- Category: Health & Fitness, Sports
- Price: Free
- Rating: 4.40/5 from 8 App Store ratings · 7 written reviews indexed
- Age rating: 17+
- Requires: iOS 12.0 · 83 MB
- Languages: American English, French (France), Italian, Japanese, Korean, Chinese (Simplified, China), Chinese (Traditional, Taiwan)
- Released: 2019-06-06
- Data updated: 2026-08-06
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/flex-stronger/id1452436164/reviews.md

## What is FLEX Stronger?

Revolutionise the way you train and prepare in the weights room! 

The FLEX Stronger app syncs to a FLEX barbell sensor to deliver real-time feedback straight to your device.

Track, manage and review training performance just like elite and professional athletes right across the globe, through the Major Leagues, UFC, Premier League and Olympic institutes.

Developed by the team at GymAware, FLEX packages everything we learned from delivering gold standard products to the pro ranks into the only VBT system developed specifically for individual use. 

The smartest system on the market, FLEX automates your entire training experience. Select an exercise. Load some weight. Lift. Completely wireless. No calibration, adjustments or exercise creation required.

Perfect for individual athletes, remote coaches and personal trainers. 

*Performance Metrics & Targets*

Precise and immediate feedback on Mean and Peak Velocity, Mean and Peak Power, Distance, Height, Eccentrics, Position and live bar path tracing.

Set targets on key performance metrics to benchmark effort across your session. 

*Group Training*

Add other lifters into your session for group training with up to three people. Complete regular training, pre-programmed workouts or even the 1RM prediction with your group. 
Training partners who complete sessions with you can collect and store their data in their own profiles once the session is done. 

Training partners can be added or removed from sessions at any time. 

*Video Mode*

Switch to video mode and record your set with synced data overlaid on the saved file. Send to friends, coaches or share online. 

Handsfree start and stop. Set your device up and lift. Your video will start, stop and crop to capture the set you just completed. 

*Automated Workouts*

Complete workouts that step you through the entire program, from exercise and weight changes to targets and rest times. 

*Create, Share and Download Workouts*

Create custom workouts directly in the app. Let FLEX run you through your new program, or share them via our Community feature with training partners or clients using FLEX. 

Looking for inspiration, download sessions from any of your connections in Community and complete them yourself. Set targets based on their results and compete and compare over the same workout. 

*1RM Predictions*

Use the automated 1RM prediction protocol to gauge current strength and readiness levels without an actual 1RM attempt. 

*Multitasking*

There are no limits in the FLEX app. Start regular sessions and add in training partners, or start a pre-programmed workout. Background the app and switch on your favourite tunes. Browse your historical results in the middle of your training sessions. Whatever you need is accessible any time. 

*Community*

Create connections in the FLEX community so you can browse their training history, download sessions (complete with their results), send workouts, train in groups. View session data live as it is uploaded set by set, and interact with fist bumps and comments directly on the platform. 

*Store and Review*

All your data is stored and reviewable in History right in your app. Data is securely backed upon our servers and retrieved on your device at any time.

## Key features

- 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

## Recent user reviews (7 of 7)

All indexed reviews: https://appshunter.io/ios/app/flex-stronger/id1452436164/reviews.md

### 1/5 — Latest update crashes with iOS 18

*2024-10-09*

App keeps crashing on iOS 18. Delete and reinstall doesn’t help either

### 4/5 — Great In-Set Interface

*2022-02-09*

Love it during the set. It’s not as intuitive looking back at information. 

What I need for 5 starts (please make this happen!!!)
1. I need ability to input pounds and not kilos when it asks what weight I’m lifting (dumb American here)

What I’d love to be able to do:
1. See all the graphs (velocity/force/work/power/bar path) more easily when reviewing results
2. If I use a tablet/laptop witha bigger screen can I see all those meters at the same

### 3/5 — App crashes frequently

*2021-04-28, version 1.10.6*

I’m sick of the app crashing in the middle of a workout. I lose my stats/progress and have to restart the workout. Sort the app out ASAP!
Consider including an option to continue favourite workouts that have not been completed.

### 5/5 — Awesome!!!

*2020-07-02*

Great technical support.  Easy to use and a great tool to help train athletes or yourself.  Would highly recommend for anyone serious about training.

### 5/5 — Great device!

*2020-06-03, version 1.8.1*

Such a cool app!! Really easy to use and I really like how it displays bar path.

### 5/5 — Happy buyer

*2019-12-09, version 1.5*

The unit shipped quick enough and after a bit of playing around I figured out how I like to use the app best. My workouts are far better compared to not having Flex. Can’t imagine going back to training without it.

### 5/5 — Great app, great device

*2019-12-03, version 1.5*

Great training feedback and helps get the most out of sessions. So easy to use. Even has a social function so I my friends can see my sessions and comment.

## Frequently asked questions about FLEX Stronger

### What is FLEX Stronger?

FLEX Stronger is a health and fitness app that uses velocity-based training (VBT) to provide real-time feedback on your weightlifting performance. It syncs with a FLEX barbell sensor to track metrics like velocity, power, and distance.

### What performance metrics does FLEX Stronger track?

FLEX Stronger precisely tracks Mean and Peak Velocity, Mean and Peak Power, Distance, Height, Eccentrics, and Position. It also offers live bar path tracing and allows you to set targets for these key performance metrics.

### Can I use FLEX Stronger for group training?

Yes, FLEX Stronger supports group training for up to three people. You can complete regular training, pre-programmed workouts, or even the 1RM prediction with your training partners.

### Does FLEX Stronger offer video recording?

Yes, FLEX Stronger has a Video Mode that records your sets with synced data overlaid on the saved file. It also features hands-free start and stop functionality for easy recording.

### How does FLEX Stronger handle workouts?

FLEX Stronger allows you to create custom workouts, download sessions from the community, and complete automated workouts that guide you through exercise, weight changes, targets, and rest times.

### What is the 1RM prediction feature in FLEX Stronger?

The 1RM prediction protocol in FLEX Stronger helps you gauge your current strength and readiness levels without needing to perform an actual 1RM attempt.

### Is FLEX Stronger available on multiple devices?

FLEX Stronger is available for iPhone, iPad, and iPod, as indicated by its supported devices.

### How often is FLEX Stronger updated?

The latest version of FLEX Stronger is 3.3.6, and it was last updated on March 13, 2026, suggesting a commitment to regular updates.

## Version history (last 5 releases)

### 3.5.1 — 2026-08-02

• Added support for the new Dip metric.
• The Exercise Library now opens with your Most Used exercises before the full list, making it quicker to find your favourites.
• Fixed a crash and made general stability improvements.

### 3.5.0 — 2026-07-26

• A new, simpler metric selector makes it easier to switch between metrics during training and review.
• Next Set Preview Alerts now show target information for non-velocity targets.
• General improvements for a smoother training experience.

### 3.4.1 — 2026-07-06

- Minor bug fixes.

### 3.4.0 — 2026-06-22

You asked, and we listened. Set targets your way, and train in peace when you need to.
• New Target Modes
    – Threshold: a single target value
    – Range: a min and max band
    – Fatigue: a % drop from your best
    – Set a target for any metric, not just velocity
• New Training Settings
    – Silent Mode mutes voice, chimes and alerts

### 3.3.6 — 2026-03-13

- Improvements based on customer feedback.
 - Bug fixes and stability improvements.

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## More apps by Kinetic Performance

- [GymAware](https://appshunter.io/ios/app/gymaware/id919006664)

All apps by Kinetic Performance: https://appshunter.io/developer/343232407

## Related topics

[qwik vbt](https://appshunter.io/ios/topics/qwik-vbt)

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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 2026-08-06.*