Kettle Muscle
Kettle Muscle

Lift with
intent.

Lift smarter. Recover faster.

An iOS strength app for people who already lift. It plans sessions around recovered muscles, logs sets locally on the gym floor, and syncs to the cloud when you're back online. Cloud sync and AI assistance are opt-in.

iPhone. iOS 17 and up.
Today screen — recovery silhouettes, today’s lift, streak.
Plan-session screen — target muscles highlighted in blue, drained in red.
Workout-in-progress screen — set logger with weight, reps, and Log set CTA.
History recovery screen — full muscle silhouettes showing red drained and green recovered.
Today

Recovery, streak, your next lift.

Plan

Targets what’s recovered. Avoids what’s cooked.

Log

Every set. Every rep. Locally first.

See

What your body has been through.

Built for the load
11+Muscle groups trackedPer-muscle freshness, not a whole-body soreness score.
0 msWait between repsSets land in local SQLite the moment you log them.
BYOAI keys, your controlApple Foundation Models on-device. OpenAI, Anthropic, Gemini via your own key.
Plan

It knows what you cooked yesterday.

Every set you log feeds a deterministic fatigue model — no AI guesswork. Push, pull, hinge, squat, carry: each muscle group has its own recovery curve. Open the app the next morning and your session is already built around what's recovered.

  • Per-muscle freshness, not whole-body soreness scores.
  • Re-plans on the fly when you swap or skip an exercise.
  • Bounded by your real history. AI never prescribes outside your envelope.
iPhone showing the Plan-Session screen with target muscles in blue and drained muscles in red. Real Kettle Muscle screenshot.
Log

Every set, locally first.

Gym wifi cuts out. Subway tunnels happen. Sets still log — written to local SQLite the instant you tap. When you're back online, the optional cloud sync catches up in the background. No signal, no spinner between reps.

  • Local-first writes — your phone is the source of truth.
  • One-tap log set, big targets, haptic on every change.
  • Optional cloud sync runs fire-and-forget once you're online.
iPhone showing the workout-in-progress screen with weight, reps, and a Log set CTA. Real Kettle Muscle screenshot.
See

Honest numbers, not streak badges.

Volume, sessions, PRs, muscle distribution — surfaced where you'd expect, not behind a paywall or a gamified ribbon. The recovery view shows what your body has actually been through this week, not a generic 'rest day.'

History top — sessions, volume, streak, bests row plus weekly card. Real Kettle Muscle screenshot.
Sessions · Streak · Bests
History middle — weekly volume line chart and personal records cards. Real Kettle Muscle screenshot.
Volume trend · PRs
History recovery — full muscle silhouettes showing red drained and green recovered. Real Kettle Muscle screenshot.
What you cooked
Kettle Muscle

We built the app we wanted.

No streak shame. No social feed. No subscription gate on basic logging. iOS-only because that's the surface we can keep fast and local-first. Android isn't a roadmap gap — it's a deliberate trade.