Turn your AI into your workout coach.

Simple Muscle is the iPhone workout tracker ChatGPT and Claude can plan in, save to, and learn from. Your AI writes the workout, you train it, and the sets you log shape the next plan.

Download on the App StoreConnect your AI

Your AI already knows you. Now it can know your training.

Tell your AI your goals and schedule. Simple Muscle adds your workouts and every set you log, so it can save a plan and change it from real numbers.

Create a plan
Set me up for 3 gym days a week. I'm 42 and coming back after a long break.
ChatGPT

Done: three full-body days that start light and add weight each week. Monday is ready in your dashboard.

3 workouts created
Fix what hurts
Barbell squats are hurting my lower back.
Claude

Swapped them for leg press at the same volume, and added light core work to rebuild slowly.

Leg Day updated
Check progress
How did my last month go?
ChatGPT

12 sessions, volume up 18%. Bench moved 60 → 65 kg; rows stalled, worth an extra set.

31 days analyzed
Published in ChatGPT

Add Simple Muscle to ChatGPT

Install it from the listing, sign in with a free Simple Muscle account, and ask for your first plan.

Add to ChatGPTClaude and other assistants
Connect your AI
ChatGPT setupClaude setup

Move seamlessly from advice to action.

Your AI creates or updates the real workout. Simple Muscle gives you the focused experience to perform it, track it, and improve it.

The workout your AI creates

Plans move straight from your AI conversation into Simple Muscle. No screenshots, copied tables, or manual plan setup.

A focused native gym experience

Track sets, reps, weight, and time with a rest timer, Live Activity, and lock-screen controls.

History your AI can use

Every workout and set becomes structured context your assistant can analyze when it updates your plan.

The plan is ready. Now just train.

The workout your AI created becomes a focused, one-set-at-a-time gym experience with everything within thumb reach.

  • Two taps per set
    Press and hold to fast-adjust, or tap the number and type the exact weight.
  • Jump to any set
    Chips show done, current, and ahead. Add an extra set in one tap.
  • Time or weight, both first-class
    Stretches and cardio get duration steppers instead of awkward rep counts.
  • Last session, in view
    Beat 8 × 60 kg. That's the whole game, so it's always on screen.
Lock screen and Apple Watch

Less phone. More workout.

Run the whole session from the lock screen or from your Apple Watch, and keep the phone face-down between sets.

  • Complete sets from the lock screen
    A real button. No unlocking between sets.
  • Rest countdown, then a nudge
    The Dynamic Island shows the timer. Music on, phone away, you still get pinged.
  • The whole workout on Apple Watch
    Follow the plan, adjust weight and reps, and log each set from your wrist.

Give your AI the history a chat alone can’t keep.

Every completed workout, set, weight, duration, and progression stays structured and ready for your assistant to analyze.

  • Weekly summary
    Workouts, volume, and time for the week.
  • Full session details
    Open any past workout, see every set you logged.
  • Per-exercise trends
    Volume chart and best set for every exercise.

We don’t charge for AI. You already have the best one.

The iPhone tracker, your web account, and the AI connection are free. Pay only to keep your iPhone workouts backed up and in sync with your account and your AI.

Try iPhone sync free for a week · no credit card required
Core workout tracker
Free
Workout tracking only
  • Unlimited workouts and exercises
  • Lock screen Live Activity
  • Rest timer with notifications
  • Full history and charts
  • Works offline on iPhone
Download on the App Store
iPhone cloud sync
$5
per month
$50
per year · save 17%
  • Cloud backup and device sync
  • Keep iPhone history current on the web
  • Keep connected AI context up to date
  • Restore workouts after changing devices
  • Your web account and AI connection work without this plan
Start in the iPhone app
Free tools and guides

Try the workflow before you connect anything.

Free, with no account needed. When you are ready, your AI can save the result to Simple Muscle.

Free tool
Free workout plan generator

Answer a few questions and get a complete weekly plan with exercises, sets, reps, rest, and progression. No account needed.

Free tool
Workout prompt builder

Turn your goal, schedule, and equipment into a reusable prompt for the assistant you already use.

Guide
ChatGPT workout plan prompt

A complete prompt to copy, a two-minute check before you train, and how ChatGPT saves and adjusts the plan.

Guide
AI workout planner

How your AI writes a plan, saves it to the tracker, and revises it from the workouts you log.

Guide
AI fitness coach

Ask your AI how training is going. It reads your logged sessions and proposes the next change for you to approve.

Questions

Simple Muscle questions, answered.

Everything you need to know about connecting your AI to an iPhone workout tracker.

What is Simple Muscle?
Simple Muscle is an AI workout tracker for iPhone that connects the assistant you already use to your workout plans, logged sets, and training history.
How does the AI workout coach work?
Connect your assistant and ask it for a plan. It saves the workouts to Simple Muscle, you train them in the iPhone app, and the sets you log become history your assistant can read. Ask it how training is going and it can review real sessions, spot trends, and change the plan from there.
Which AI assistants work with Simple Muscle?
Simple Muscle supports ChatGPT, Claude, OpenClaw, and other assistants that can connect through the open Model Context Protocol (MCP).
How do I add Simple Muscle to ChatGPT?
Open the published Simple Muscle plugin listing in ChatGPT, install it, and sign in with your Simple Muscle account when prompted. Claude and other MCP assistants can use the connection URL on our setup page.
What workout data can my AI access?
After you approve a connection, your assistant can request structured plans, schedules, exercises, targets, notes, your weight-unit preference, logged sets, completed sessions, and per-exercise progress. You can disconnect it to stop future access.
Does Simple Muscle include its own AI coach?
No. Simple Muscle connects your existing AI assistant to structured workout data, so you keep using the assistant that already knows your goals, schedule, and preferences.
Can I use Simple Muscle for free?
Yes. The core iPhone workout tracker is free and works offline, and the web dashboard and MCP connection do not require an iOS subscription. Keeping iPhone workouts backed up and synced with those connected services includes a seven-day free trial, then costs $5 per month or $50 per year.
Is my workout data private?
Workout tracking works locally on your iPhone, and Simple Muscle does not sell your workout data or use it for advertising. Personal workout data is available only through connections you authorize and is returned when the assistant requests it through Simple Muscle.

Your AI already knows you. Give it your training.

Connect Simple Muscle and turn personalized advice into workouts you can perform, track, and improve.

Download on the App StoreConnect your AI