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ISOBEAST is purpose-built for an ISO-BAR (isometric bar) with numbered strap slots. The app tracks hook position (slots 1–36), which is the key to isometric progressive overload — each slot trains your muscles at a different length, and ISOBEAST treats each slot as its own independent progression track.

Without an ISO-BAR you can still use the free-mode logging to track any timed isometric hold, but the slot-based progression won't apply.

Open a session, pick your exercise, and you'll see a logging form pre-filled with your targets from last time. Enter your force reading, your hold duration, choose the hook slot (1–36), then tap the green checkmark. That's three taps — and the app records the set, scores your performance, and starts the rest timer automatically.

You can also adjust targets before logging if you need to warm up or go heavier than prescribed.

After every set, ISOBEAST calculates a performance ratio R = min(force / target_force, duration / target_duration). Based on R, one of four outcomes applies:

• Success + Large progress (R ≥ 1.05): the limiting dimension increases by 5%.
• Success + Small progress (1.03 ≤ R < 1.05): the limiting dimension increases by 3%.
• Maintain (0.95 ≤ R < 1.03): targets hold steady.
• Failure (R < 0.95): targets decrease by 5%.

No AI, no black box. The same inputs always produce the same outputs. You can see exactly why your targets changed after every session.

ISOBEAST ships with 9 read-only program templates from the ISO-BAR manual:

• The Promethean — 6-second holds with double progression (force and duration both advance).
• 6×6 — Fixed percentage of your tested one-rep max; 6 sets per exercise.
• Military Power — Max-effort singles with slot variation to hit multiple muscle lengths.
• Iron Man — Long conditioning holds for endurance and tendon health.
• One-Rep Max Testing — Averages peak force attempts to establish your 1RM baseline.

All programs resolve into the same session flow — you log sets the same way regardless of program.

Yes. Set logging, rest timers, and progression calculations all work fully offline. When your connection is restored, data syncs automatically to your private cloud account. A banner appears at the top of the app if you're offline so you always know your connection status.

The ISO-BAR has 36 numbered strap slots that determine the height of the bar — and therefore the muscle length at which you're generating tension. Shorter slots train the muscle in a shortened position; higher slots train at a lengthened position.

Isometric strength is highly position-specific: gains at slot 10 don't automatically transfer to slot 25. ISOBEAST tracks each slot independently so you can deliberately build strength at every point in the range of motion.

After you log a set, a rest timer starts automatically. The duration is based on your program prescription, hold mode, or a default (20 seconds for timed holds, 60 seconds for max-effort holds). A pill-shaped timer appears at the bottom of the screen.

If you background the app, a local notification fires when rest ends — no server required, no internet needed. Tap "Skip" on the pill to dismiss the timer early and get back to work.

Yes. Your workouts sync to a private, encrypted cloud database (Supabase). All authentication tokens are stored in the iOS secure keychain, never in plain storage. ISOBEAST does not include advertising SDKs, does not track you across apps or websites, and never sells personal data.

Crash diagnostics are sent to Sentry for app stability — that's it. See the Privacy Policy for the complete breakdown.

iOS 16.0 or later. iPhone only (all screen sizes supported, including 6.7" Pro Max). No iPad version at launch.

Use the contact form below to request deletion. Include the email address associated with your ISOBEAST account in your message. We'll permanently remove your account, workouts, routines, and progression data within 30 days.