Comparison

Flex AI Workout Trainer & Log vs NextRep

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

NextRep

This AI-powered fitness planner creates personalized workout routines based on your experience, equipment, and goals. It tracks your progress, manages recovery, and offers a large exercise library with video guides.

Highlights
  • AI-generated custom workout routines
  • Progressive overload tracking
  • Injury management safeguards
  • Detailed gym logging (sets, reps, weight, RPE)
  • Rest timer and history analysis
  • 1,700+ exercises with video instructions
  • Home and gym workout compatibility
Features
Read full description

Build muscle, gain strength, and stay consistent with NextRep, the AI workout planner that adapts to you. Combine smart planning with a detailed gym tracker so you never have to guess what to do next. Whether you’re into bodybuilding, powerlifting, or just want to get fit, NextRep helps you hit your goals using the equipment you actually have available. SMARTER TRAINING WITH AI (PRO) Stop following static PDFs or generic templates. Let the AI personal trainer generate the perfect plan for you. ◆ Custom Workout Routines: Get a plan built for your experience, schedule, and specific equipment (Home or Gym). ◆ Progressive Overload: The AI ensures you increase weight and intensity at the right time to maximize hypertrophy and strength gains. ◆ Injury Management: Built-in safeguards that consider recovery and work around injured body parts automatically. TRACK LIKE A PRO Turn every session into data you can use. NextRep is the ultimate weightlifting logger. ◆ Simple Logging: Track sets, reps, weight, and RPE with ease. ◆ Rest Timer: Auto-start rest timers between sets to keep your intensity high. ◆ History & Trends: View your 1RM (One Rep Max) trends, volume, and personal records over time. ◆ Strength Score: Visualize your progress with a breakdown per muscle group. RECOVERY & EXERCISES ◆ 1,700+ Exercises: Huge library with video instructions and demos (Squat, Bench Press, Deadlift, and more). ◆ Recovery Insights: See which muscles are fresh and which need rest before your next gym session. BUILT FOR REAL LIFE ◆ Home & Gym: Seamlessly switch between bodyweight workouts and full gym setups. Subscription & Free Trial: NextRep is free to download and includes a 7-day free trial with full access to all features. After the trial period ends, an active subscription is required to continue using the app. Your subscription grants you access to: • AI Workout Generation • Training Logs & History • Muscle Recovery Analysis • Strength Progression Tracking Subscription Information: ◆ Life Time access ◆ Subscriptions are available as a monthly or yearly plan. ◆ Payment will be charged to your Apple Account at confirmation of purchase (or after your free trial ends). ◆ Your subscription will automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period. Your account will be charged for renewal within 24 hours prior to the end of the current period. ◆ You can manage your subscriptions and turn off auto-renewal by going to your Account Settings on the App Store after purchase. Any unused portion of a free trial period will be forfeited when you purchase a subscription. Privacy Focused: Your data belongs to you. Download NextRep today—the smarter way to plan, track, and grow. Privacy Policy: https://nextrep-ai.app/en/legal/privacy/ Terms of Use: https://nextrep-ai.app/en/legal/terms/

Screenshots

Flex AI Workout Trainer & Log4 screens
NextRep4 screens

Verdict

The call

The clearest difference is ads: Flex AI Workout Trainer & Log at none against NextRep's shown. Flex AI Workout Trainer & Log also leads on ratings volume (2.4K vs 1). NextRep's advantage is rating (5.0 vs 4.6) and iOS requirement (15.5 vs 18.0). On price, update cadence, in-app purchases and monetization model 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 NextRep sells 3 in-app purchases, starting at $7.99 per month. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

NextRep 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

Flex AI Workout Trainer & Log ships an update every 9 days, NextRep every 2 weeks. Both last shipped on October 24, 2026.

Scorecard4 real differences · 6 level
Flex AI Workout Trainer & Log versus NextRep: the parameters behind the verdict, then further details
ParameterFlex AI Workout Trainer & LogNextRep
PriceFreeFree
Rating4.6 (2.4K ratings)5.0 (1 ratings) — better
Positive reviews69.0% of reviews—
Number of ratings2.4K — better1
Update frequencyEvery 9 days — betterEvery 2 weeks
AdsNo — betterYes
In-app purchasesYesYes
MonetizationFreemiumFree with in-app purchases
DevicesiPhone, Apple WatchiPhone, iPod
Requires iOS18.015.5 — better
Further details — not scored
Size574 MB111 MB
Age rating17+4+
DeveloperFlex Artificial Intelligence Inc.AppStack X

Customer experience

Flex AI Workout Trainer & Log

All ratings2,412 ratings
Positive92.0%
Neutral2.6%
Negative5.4%
Written reviews310 reviews
Positive69.0%
Neutral6.5%
Negative24.5%

NextRep

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

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

NextRep

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
3 purchases

NextRep

Subscriptions2
  • NextRep Monthly7 Days trial$7.991 Month
  • NextRep Annual7 Days trial$39.991 Year
One-time1
  • English US$9.99

Questions

Is Flex AI Workout Trainer & Log free?
Flex AI Workout Trainer & Log is free to download, with in-app purchases available.
Is NextRep free?
NextRep is free to download, with in-app purchases available.
Which has better reviews, Flex AI Workout Trainer & Log or NextRep?
NextRep is rated higher. Flex AI Workout Trainer & Log averages 4.6 out of 5 from 2.4K ratings, while NextRep averages 5.0 from 1 ratings.
Do Flex AI Workout Trainer & Log or NextRep have ads?
NextRep shows ads; Flex AI Workout Trainer & Log does not.
Which is updated more often, Flex AI Workout Trainer & Log or NextRep?
Flex AI Workout Trainer & Log ships an update every 9 days, and NextRep every 2 weeks. Most recently, Flex AI Workout Trainer & Log was updated on October 24, 2026 and NextRep on October 24, 2026.

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