Flex AI Workout Trainer & Log

Name: Flex AI Workout Trainer & Log
Rating: 4.7 (2320 reviews)
Author: Flex Artificial Intelligence Inc.

Fitness Tracker & Gym Planner

Free · In‑App Purchases

2.3K Ratings
Ages

9+
Years
Category

Health & Fitness
Developer

Flex Artificial Intelligence Inc.
Language

EN
+ 12 More
Size

560.8
MB

Flex AI is the world’s first true AI personal trainer — built for lifters who want to train smarter, progress faster, and perfect their form. Whether you’re chasing size, strength, or consistency, Flex uses real-time AI to guide every rep, adjust your program, and keep you motivated through challenges, leaderboards, and streaks. - Your AI Coach, Every Rep Personalized workouts built automatically by AI personas that learn your goals, history, and preferences. Real-time form feedback powered by patented computer-vision AI — get instant corrections on squats, bench, deadlift, rows, and more. Adaptive progression and deloading backed by sports-science principles — no spreadsheets, no guesswork. - Train Smarter — See Results AI tracks your strength curve and increases weight when you’re ready. Visual progress graphs show PRs, volume, and recovery trends. Track sets, reps, and tempo with a tap — or automatically with Apple Watch. - Stay Motivated & Connected Join a global community of lifters. Compete on leaderboards, build streaks, and earn badges. Post progress photos, celebrate milestones, and share results. - Accessible to Everyone Free to start with all core features included. Upgrade anytime for advanced AI coaching and premium analytics. Designed for all experience levels — from beginners to pros. - Why Flex AI Real-time AI form feedback (patented) Adaptive, science-based programming Progress tracking & recovery insights Gamified streaks + leaderboards Apple Watch integration Built for hypertrophy & strength goals Start Training Smarter — Today Download Flex AI and experience personal training powered by real AI. Perfect your form. Unlock your best lift. Train smarter — free on iPhone + Apple Watch.

Ratings & Reviews

4.7

out of 5

2.3K Ratings

Best Workout App for Intermediate and Advanced Training
05/24/2024

XJRGU25
I’ve been weight training for about 15 years and one of the biggest keys to success in the gym is consistency workout to workout. Flex is built exactly for this. It allows you to build your own workouts in a simple, easy to use format. There are premade workouts available for beginners but I don't think this is really the app’s strength. It remembers your last weight and set for each exercise and carries it over to the next workout. It tracks your rest (which you can customize) And if you make modifications intra-workout, you can save those for the next time as well. The stats dashboard is helpful for tracking progress, though could use some improvement and more detail. Try it out for free, but if you have an apple watch, you’ll definitely want to pay for it, the logging on the watch has changed my ability to stay focused and keep my phone away while working out. Overall an amazing app if you want a highly customizable, simple interface logging app that doesn't push a specific training style or set of workouts.

Developer Response
Wow, thanks for taking the time sharing your detailed review with everyone! 12 years gymming is very impressive, that’s the sort of lifestyle we try to help promote 💪🏻
Best Workout App for Intermediate and Advanced Training
05/24/2024

XJRGU25

I’ve been weight training for about 15 years and one of the biggest keys to success in the gym is consistency workout to workout. Flex is built exactly for this. It allows you to build your own workouts in a simple, easy to use format. There are premade workouts available for beginners but I don't think this is really the app’s strength. It remembers your last weight and set for each exercise and carries it over to the next workout. It tracks your rest (which you can customize) And if you make modifications intra-workout, you can save those for the next time as well. The stats dashboard is helpful for tracking progress, though could use some improvement and more detail. Try it out for free, but if you have an apple watch, you’ll definitely want to pay for it, the logging on the watch has changed my ability to stay focused and keep my phone away while working out. Overall an amazing app if you want a highly customizable, simple interface logging app that doesn't push a specific training style or set of workouts.
Developer Response 07/05/2023
Wow, thanks for taking the time sharing your detailed review with everyone! 12 years gymming is very impressive, that’s the sort of lifestyle we try to help promote 💪🏻
Great App
07/07/2023

~(0_0~) ZombieGhost
I’ve very often struggled to maintain a consistent workout routine without relying on a trainer. I started using this app to supplement my regular training routine. I’ve used it on days where I just wasn’t sure what to focus on, and it has helped by making it easy to target a specific muscle group or filter by equipment. The smart progression and auto tracking has really helped me see tangible progress in my training. It’s taken a lot of the effort out of planning my workouts, making actually going to the gym much easier and enjoyable.I do like how it is easy to swap out an exercise, or adjust the number of reps or weights on the fly. This has been useful when the gym is busy and I may not have access to the right equipment, it makes it really easy to adapt a workout. The animations and descriptions of what to do in an exercise are also really helpful.I would recommend this to anyone who struggles to track and maintain a consistent workout plan.

Developer Response
Thank you so much for your review! Please let us know if there's any way we can further improve the app for you by sending us a report/message in app.
Great App
07/07/2023

~(0_0~) ZombieGhost

I’ve very often struggled to maintain a consistent workout routine without relying on a trainer. I started using this app to supplement my regular training routine. I’ve used it on days where I just wasn’t sure what to focus on, and it has helped by making it easy to target a specific muscle group or filter by equipment. The smart progression and auto tracking has really helped me see tangible progress in my training. It’s taken a lot of the effort out of planning my workouts, making actually going to the gym much easier and enjoyable.I do like how it is easy to swap out an exercise, or adjust the number of reps or weights on the fly. This has been useful when the gym is busy and I may not have access to the right equipment, it makes it really easy to adapt a workout. The animations and descriptions of what to do in an exercise are also really helpful.I would recommend this to anyone who struggles to track and maintain a consistent workout plan.
Developer Response 07/10/2023
Thank you so much for your review! Please let us know if there's any way we can further improve the app for you by sending us a report/message in app.
Great Work Out app for Gym and At Home!
07/06/2022

Karmma333
I have been through my fair share of work out apps, everyone of which limits what I can do and what types of work outs I can create for ME, so I wasn’t expecting much from Flex when I saw it advertised thinking it was like others but decided to try it out. I was pleasantly surprised when I saw I can create my own work out’s however many that it, my own work out plan. They let you completely customize and decide what you are going to be doing with your own work outs for free. They do provide work outs themselves and plans but you have to pay for some of them which is only expected. For someone who has a work out plan in their mind and just need the structure for said plan this app is perfect.
Great Work Out app for Gym and At Home!
07/06/2022

Karmma333

I have been through my fair share of work out apps, everyone of which limits what I can do and what types of work outs I can create for ME, so I wasn’t expecting much from Flex when I saw it advertised thinking it was like others but decided to try it out. I was pleasantly surprised when I saw I can create my own work out’s however many that it, my own work out plan. They let you completely customize and decide what you are going to be doing with your own work outs for free. They do provide work outs themselves and plans but you have to pay for some of them which is only expected. For someone who has a work out plan in their mind and just need the structure for said plan this app is perfect.
Good for detailed tracking
11/15/2024

wakeup2
Great for saving workouts whether these are cardio, calisthenics, or strength training. The app has a bank of exercises to choose from and if needed, you can create custom ones. You can group exercises into supersets and set rest times between reps. Also, if competition and point systems motivate you to exercise, then this app is for you! You earn points for every workout and can unlock achievements for more points. If you really want to unleash your competitiveness, view the rankings. It’ll really humble you. I left off a star because it’d be more convenient if I could add workouts anytime like the MyFitness App, which allows you to manually fill out the date and time for any previous day. I like this because sometimes I forget to track workouts and this app (at least the free version) doesn’t allow you to add a workout to a previous day.
Good for detailed tracking
11/15/2024

wakeup2

Great for saving workouts whether these are cardio, calisthenics, or strength training. The app has a bank of exercises to choose from and if needed, you can create custom ones. You can group exercises into supersets and set rest times between reps. Also, if competition and point systems motivate you to exercise, then this app is for you! You earn points for every workout and can unlock achievements for more points. If you really want to unleash your competitiveness, view the rankings. It’ll really humble you. I left off a star because it’d be more convenient if I could add workouts anytime like the MyFitness App, which allows you to manually fill out the date and time for any previous day. I like this because sometimes I forget to track workouts and this app (at least the free version) doesn’t allow you to add a workout to a previous day.

Flex 3.0 — Your AI Personal Trainer Is Here Meet Lex, your new AI personal trainer built into Flex. Get personalized workouts based on your goals, progress, and recovery — no templates, just smart training that adapts to you. What’s New: • Lex: Chat with your AI trainer to build workouts, routines, or get expert fitness advice. • Form Feedback: Get real-time AI tips to perfect your form and avoid injuries. • AI Progression: Smarter progressive overload that adjusts automatically for better results. • Performance improvements and bug fixes.

Version 3.0.2

Nov 29

Data Linked to You

The following data may be collected and linked to your identity:
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- Usage Data
- Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

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Ratings & Reviews

What’s New

Version 3.0.2

App Privacy

Data Linked to You

Accessibility

Information

Supports

Family Sharing

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