Flex: the Free Hypertrophy Workout Planner
Science-based training plans, an instant workout generator, guided audio yoga, and progress tracking — all in one place, and all completely free. Follow a proven plan, build your own, or let the generator hand you a session that fits the time and equipment you have right now.
No card, no trial, no paywall — you can even train as a guest before creating an account.
What you can do
Science-based training plans
Start with ready-made hypertrophy plans built around progressive overload and sensible weekly volume, or design your own split in the plan builder — exercises, rep ranges, circuits, and rest days included.
Instant workout generator
Short on time or away from your usual gym? Tell the generator your available minutes, equipment, and muscle focus, and it builds a complete session you can start immediately — no planning required.
Guided audio yoga
Audio-guided yoga sessions walk you pose by pose with spoken transitions, a choice of voice, and optional background music — ideal for mobility work and recovery days without staring at a screen.
Logging, history & stats
Log sets, reps, and weight as you train, then watch the data add up: personal records, progression charts, weekly muscle-group recaps, and a full workout history.
Trainer & client tools
Coaches get a trainer dashboard to manage clients and groups, assign plans, and review exactly what each client logged — clients just open the app and train.
Community plans
Browse plans shared by other lifters, copy one into your account with a tap, or share your own plan with a link.
How it works
- Pick your starting point. Choose a ready-made hypertrophy plan, build a custom split, or generate a one-off workout for today.
- Train with guidance. Run each session in the app — sets, reps, rest timers, and audio cues keep you moving.
- Track what happens. Every logged set feeds your history, personal records, and progression charts, so next week you know exactly what to beat.
100% free. Every feature — plans, the generator, guided yoga, logging, stats, and trainer tools — is free to use. No payment step, no premium tier, no card required.
Frequently asked questions
Is Flex really free?
Yes. Every feature — training plans, the workout generator, guided yoga, logging, stats, and trainer tools — is free. There is no payment step, no premium tier, and no card required.
Do I need an account to start?
No. You can generate and run a workout as a guest right away. A free account adds saved plans, workout history, and progress stats that follow you across devices.
How does the instant workout generator work?
Tell it how long you have, what equipment is available, and which muscles you want to focus on. It builds a complete session — exercises, sets, reps, and rest — that you can start immediately.
What are the guided yoga sessions like?
Each session is audio-guided pose by pose, with spoken transitions, your choice of voice, and optional background music — so you can follow along without watching a screen.
Can personal trainers use it with clients?
Yes. The trainer dashboard lets you manage clients and groups, assign workout plans, and review what your clients actually logged.
Does it work on my phone?
Yes. Flex runs in any modern browser and can be installed to your home screen as an app, with workouts and guided audio available wherever you train.
From the Learn library
Evidence-based guides on training, programming, and recovery:
- How Many Sets Per Muscle Per Week Do You Actually Need?
- The Dumbbell-Only Push/Pull/Legs Split That Actually Works
- Progressive Overload: The Only Training Principle You Can't Skip
- Your First 12 Weeks of Lifting: A Beginner's Hypertrophy Plan
- How Many Reps Build Muscle? What Rep Ranges Really Do
- Yoga for Lifters: What It Fixes, What It Doesn't