Flex AI: Your AI Personal Trainer
Flex AI is an AI-powered personal training app that provides real-time workout guidance, form correction, and personalized training programs while tracking progress through an intuitive interface.
https://apps.apple.com/app/flex-ai-workout-trainer-log/id1446354547?ref=producthunt
Product Information
Updated:Nov 21, 2025
What is Flex AI: Your AI Personal Trainer
Flex AI is the world's first true AI personal trainer app designed for fitness enthusiasts who want to train smarter and achieve better results. The app features an AI trainer named Lex that creates personalized workout plans based on users' goals, progress, and recovery needs. Whether users are focused on building muscle, increasing strength, or maintaining consistency, Flex AI offers a comprehensive solution that combines artificial intelligence with proven training principles.
Key Features of Flex AI: Your AI Personal Trainer
Flex AI is an advanced AI-powered workout tracking and personal training app that offers personalized workout plans, real-time form feedback, and adaptive progression. The app features Lex, an AI personal trainer that creates customized workouts based on users' goals, history, and preferences. It provides comprehensive tracking capabilities, including weight, reps, and sets monitoring, while offering motivation through challenges, leaderboards, and streaks. The app integrates with Apple Watch for hands-free tracking and includes features for both beginners and experienced lifters.
AI Personal Trainer (Lex): An AI-powered coach that creates personalized workouts, provides real-time form feedback, and adjusts training programs based on individual progress and goals
Smart Progress Tracking: Automatically tracks and visualizes workout progress through charts, monitors personal bests, and provides detailed exercise statistics
Adaptive Programming: Automatically adjusts weight, reps, and sets to optimize strength gains and ensure proper progressive overload
Social Features & Gamification: Includes challenges, leaderboards, streaks, and community features to keep users motivated and engaged
Use Cases of Flex AI: Your AI Personal Trainer
Beginner Workout Guidance: Helps newcomers to fitness start their journey with proper form and appropriate progression
Strength Training Optimization: Assists experienced lifters in maximizing their gains through precise tracking and intelligent load management
Rehabilitation Training: Supports users in maintaining proper form and gradual progression during recovery from injuries
Pros
Comprehensive AI-powered form feedback and coaching
Detailed progress tracking and visualization
Apple Watch integration for hands-free workout tracking
Cons
Cannot add workouts retroactively in the free version
Premium features require subscription
Some users report the app's strength is not in pre-made workouts for beginners
How to Use Flex AI: Your AI Personal Trainer
Download and Install: Download Flex AI from the App Store and install it on your iPhone. The app requires iOS 17.0 or later.
Create Account & Set Goals: Sign up for an account and set your fitness goals (building muscle, losing weight, improving strength etc.). The app will use this to personalize your experience.
Meet Your AI Trainer Lex: Get introduced to Lex, your AI personal trainer who will create personalized workouts based on your goals, history and preferences.
Choose or Create Workout Plan: Either select from premade workout programs or create your own custom workout routine. You can build workouts by selecting exercises from the exercise library.
Start Working Out: Begin your workout session. The app will guide you through each exercise with proper form instructions and real-time AI feedback on your technique.
Track Your Progress: Log your sets, reps and weights for each exercise. The app automatically tracks your progress and visualizes it through charts and statistics.
Get Form Feedback: Use the AI form feedback feature by recording your exercise form. The AI will analyze and provide instant corrections to improve your technique.
Adjust Training Plan: The AI will automatically adjust your workout difficulty, weights, sets and reps based on your performance to ensure optimal progression.
Stay Motivated: Participate in challenges, earn achievements, compete on leaderboards and track your streaks to stay motivated.
Connect Apple Watch (Optional): For Premium users, sync with Apple Watch to log workouts hands-free and get real-time coaching on your wrist.
Flex AI: Your AI Personal Trainer FAQs
Flex AI offers personalized workouts built by AI, real-time form feedback using computer vision AI, adaptive progression tracking, visual progress graphs, workout tracking with Apple Watch integration, and social features like leaderboards and streaks.
Flex AI: Your AI Personal Trainer Video
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