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Flex AI Workout Trainer & Log

Flex AI Workout Trainer & Log

Fitness Tracker & Gym Planner

2.4K ratings
310 reviews
💪 Health & Fitness
⚽ Sports
Free
In-App Purchases

Details

Released
December 14, 2021
Updated
April 9, 2026

Features

Developer

Flex Artificial Intelligence Inc.
✨Promote your app ✨
Flex AI Workout Trainer & Log screenshot #1 for iPhone
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About

This app uses AI to provide personalized workout plans and real-time form feedback for weightlifters. It tracks progress, offers adaptive progression, and includes motivational features like leaderboards and streaks. It's designed for all experience levels, from beginners to pros.

✓AI personal trainer
✓Real-time form feedback
✓Personalized workout plans
✓Adaptive progression
✓Strength tracking
✓Community leaderboards
✓Apple Watch integration
Show original description

What users say about Flex AI Workout Trainer & Log

Reviews of Flex AI Workout Trainer & Log are mostly positive: the Health & Fitness app is rated 4.6/5 from 2.4K App Store ratings. What users like most: detailed workout tracking, customizable workouts. Top complaints: glitches and bugs, expensive premium subscription. Summarized from real user reviews.

Positive things

  • 🚀Detailed workout tracking
  • 👍Customizable workouts
  • 🔒Comprehensive exercise library
  • 💡Helpful progress tracking
  • 👍Clean and intuitive interface
  • 🚀Seamless Apple Watch integration

Negative things

  • 🐛Glitches and bugs
  • 💰Expensive premium subscription
  • 🔒Limited functionality without premium
  • 🐛Inconsistent rest timer
  • 🐛Workout data loss
See all reviews

What's New in Flex AI Workout Trainer & Log

3.1

April 9, 2026

• New design: Flex now has a revamped interface with a modern look and improved usability. • Smarter AI trainer: Lex now creates and progresses your workouts with even more precision and intelligence. • Performance improvements and bug fixes.

More
26

Subscriptions & In-App Purchases

Premium Subscription Monthly

1 month subscription for premium membership

$12.991 Month
Price Updates
October 22, 2026→$12.99
August 9, 2026→$1.99
March 18, 2026→$12.99
February 1, 2026→$12.99
November 6, 2025→$12.99
How to cancel Flex AI Workout Trainer & Log subscription ⁉️

Events

Read more about Introducing Flex 3.0
Event EndedMajor Update

Introducing Flex 3.0

Your AI Personal Trainer

Nov 11, 2025 — Dec 12, 2025

Read More

Read more about AI-Powered Form Feedback
Event EndedMajor Update

AI-Powered Form Feedback

Spot mistakes and refine your technique.

Nov 11, 2025 — Dec 12, 2025

Read More

Read more about Introducing Flex challenges
Event EndedChallenge

Introducing Flex challenges

Stay active to earn points & achievements

Aug 31, 2024 — Sep 29, 2024

Read More

See All

User reviews

Most RecentHighest RatedLowest Rated

Awesome App!

Flex AI is a great app. Gives lots of information on how to properly do the exercises and has the tracking and timers in the workout as well.
FFlowyJo

Stuck

Can’t get past the auto progression page
KKayyyRainee

Signing up

This seems like a really good app but when I try to sign up for free I get stuck on the Progression overload is key to improve screen. If someone can help me that would mean a lot
TTacoPotato99

Rubbish

I downloaded the app a few days ago and each time it freezes upon trying to set it up. Can’t be bothered anymore
FFJ7402

Love the app but they deleted my account and there is no tech support

I’ve been using the app for years and enjoyed it. However I have been locked out of my account for weeks and trying to get in touch with their support department for and they have not responded. Very disappointing. Due to the lack of tech support, I do not recommend this app
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See 305 more reviews

User experience

🐞

Reported Bugs

3 issues

App crashes on iOS 16 update

Bug

Inability to log workouts on previous days

Bug

Inconsistent syncing between app and Apple Watch

Bug
✨

Requested Features

4 requests

Offline workout mode

Feature

Ability to save and reuse custom workout plans

Feature

Muscle group targeting and analytics

Feature

Social features and community integration

Feature

FAQ

What does Flex AI Workout Trainer & Log do?

This app acts as an AI personal trainer for weightlifters. It provides personalized workout plans, real-time feedback on exercise form using computer vision, and adaptive progression based on sports science principles. It also includes features to track progress, stay motivated, and connect with a community.

What are the key features of this fitness app?

Key features include an AI coach that generates personalized workouts, patented real-time form feedback for exercises like squats and deadlifts, adaptive progression and deloading, strength curve tracking, visual progress graphs, and integration with Apple Watch. It also offers gamified elements like leaderboards and streaks.

How much does Flex AI Workout Trainer & Log cost?

The app is free to start, with all core features included. Users can upgrade at any time for advanced AI coaching and premium analytics. This freemium model allows access to essential training tools without an initial cost.

What devices is this workout app compatible with?

The app is designed for iPhone and Apple Watch. It leverages Apple Watch for automatic tracking of sets, reps, and tempo, enhancing the user experience for those who use Apple's wearable technology.

Who is this app designed for?

This app is built for lifters of all experience levels, from beginners to professionals. It's particularly beneficial for those focused on hypertrophy (muscle growth) and strength goals who want to train smarter, progress faster, and perfect their lifting technique.