Comparison

Flex AI Workout Trainer & Log vs Boost

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Flex AI Workout Trainer & Log

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.

Highlights
  • AI personal trainer
  • Real-time form feedback
  • Personalized workout plans
  • Adaptive progression
  • Strength tracking
  • Community leaderboards
  • Apple Watch integration
Features
Read full description

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.

About

Boost

Features
Read full description

Boost is your fitness companion built to match your goals, your level, and your progress. Start with a quick survey, then follow a workout plan that adapts as you log your training. What you can do with Boost Personalized workout plans: Tell us your goal (muscle gain, weight loss, strength, or general fitness) and your preferences, then get a plan tailored to you. Adaptive training: Your sets, reps, and recommended weights adjust based on your performance and consistency. Build your own routines: Edit your plan anytime or create a custom routine from scratch. Exercise library (180+ exercises): Browse a large library with guided videos to help you train with better form and confidence. Simple, user-friendly design: Log workouts fast, explore exercises easily, and stay consistent with minimal effort. Boost helps you stay organized, progressive, and motivated, one workout at a time. Download Boost and start training today. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Flex AI Workout Trainer & Log4 screens
Boost4 screens

Verdict

The call

The clearest difference is rating: Boost at 5.0 against Flex AI Workout Trainer & Log's 4.6. Boost also leads on iOS requirement (15.1 vs 18.0). Flex AI Workout Trainer & Log's advantage is ratings volume (2.4K vs 1). On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Flex AI Workout Trainer & Log sells 8 in-app purchases, starting at $12.99 per month and Boost sells 1 in-app purchase, starting at $12.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Boost holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Flex AI Workout Trainer & Log has 2.4K ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 9 days. Both last shipped on October 24, 2026.

Scorecard3 real differences · 7 level
Flex AI Workout Trainer & Log versus Boost: the parameters behind the verdict, then further details
ParameterFlex AI Workout Trainer & LogBoost
PriceFreeFree
Rating4.6 (2.4K ratings)5.0 (1 ratings) — better
Positive reviews69.0% of reviews—
Number of ratings2.4K — better1
Update frequencyEvery 9 daysEvery 9 days
AdsNoNo
In-app purchasesYesYes
MonetizationFreemium—
DevicesiPhone, Apple WatchiPhone, iPad, iPod — better
Requires iOS18.015.1 — better
Further details — not scored
Size574 MB43 MB
Age rating17+4+
DeveloperFlex Artificial Intelligence Inc.ALRAWAFED TRADING AND INVESTMENT,

Bugs and requests

Flex AI Workout Trainer & Log

Reported bugs

3 issues
  • App crashes on iOS 16 update
  • Inability to log workouts on previous days
  • Inconsistent syncing between app and Apple Watch

Requested features

4 requests
  • Offline workout mode
  • Ability to save and reuse custom workout plans
  • Muscle group targeting and analytics
  • Social features and community integration

Boost

Not enough reviews yet to summarise bugs or requests.

In-app purchases

8 purchases

Flex AI Workout Trainer & Log

Subscriptions6
  • Premium Subscription Monthly$12.991 Month
  • Premium Plus Monthly$29.991 Month
  • Premium Plus Family Monthly$69.991 Month
Show 3 more
  • Premium Yearly Subscription$79.991 Year
  • Premium Plus Yearly7 Days trial$191.991 Year
  • Premium Plus Family Yearly7 Days trial$499.991 Year
One-time2
  • 1 Month Free PremiumFree
  • Lifetime Free PremiumFree
1 purchases

Boost

Subscriptions1
  • Boost Subscription7 Days trial$12.991 Month

Questions

Is Flex AI Workout Trainer & Log free?
Flex AI Workout Trainer & Log is free to download, with in-app purchases available.
Is Boost free?
Boost is free to download, with in-app purchases available.
Which has better reviews, Flex AI Workout Trainer & Log or Boost?
Boost is rated higher. Flex AI Workout Trainer & Log averages 4.6 out of 5 from 2.4K ratings, while Boost averages 5.0 from 1 ratings.
Do Flex AI Workout Trainer & Log or Boost have ads?
Neither Flex AI Workout Trainer & Log nor Boost shows ads.
Which is updated more often, Flex AI Workout Trainer & Log or Boost?
Flex AI Workout Trainer & Log ships an update every 9 days, and Boost every 9 days. Most recently, Flex AI Workout Trainer & Log was updated on October 24, 2026 and Boost on October 24, 2026.

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