Workouts, built around your gym

Marrow 1.4 turns the strength log into a training module: a program made from the equipment you actually have, a logger that puts last time's numbers in front of you, a rest timer, and a body map that shows what the week covered. All of it is free, and every finished workout is written to Apple Health.

All Marrow guides: Workouts · Apple Watch · Connect your AI · Files · Support

The logger

• Last time in front of you. Each set shows what you did last time in grey. Tap it to take the same, type to change it. A set is logged as soon as it has numbers; there is nothing to tick. Reps first, then weight, in the unit you chose in Settings.
• Rest timer. One rest length, set once in Settings, Workouts, that every exercise follows. The clock sits in the logger's header: tap to start it, tap again to adjust. If you leave the app during a rest, a local notification ("Rest is over") brings you back; iOS asks for notification permission the first time a timer starts. Change the rest for one exercise and it applies to that workout only.
• Warm-ups and supersets. Barbell and plate-loaded lifts get warm-up sets automatically (switch it off per exercise or in Settings). Warm-ups are logged but never counted toward volume, records or the muscle map. Pair two exercises as a superset and the logger scrolls between them.
• Minimize and come back. A workout in progress survives leaving the app, a phone call, or a restart. It is restored exactly where you were, rest clock included.
• Finish writes to Apple Health. The session lands in Apple Health as a workout, next to the ones your watch recorded. Delete it in Marrow and it is removed from Apple Health too.

777 exercises, with photos

The exercise library ships inside the app: 777 movements, each with the muscles it works, the equipment it needs and a two-frame photo of the movement. Photos load on demand from a public, open-source repository (free-exercise-db on GitHub); nothing about you is sent there. The picker keeps a Recent shelf and a search, and anything the library lacks you create yourself, with the muscles it should credit.

Already had a strength log? Everything you logged in earlier versions is still there. Marrow matched your old exercise names to the library once, so "Bench Press" and the library's "Barbell Bench Press" are the same lift with one history, one chart and one set of records.

The body map

Data, Fitness, Muscles is a front-and-back figure of 22 muscles. Every working set credits the primary muscles it worked in full and the secondary muscles by half; the figure fills in as the week goes and you can look at 1, 4, 8 or 12 weeks. Tap a muscle for its own page. The same figure appears on each exercise's page and on every session's summary.

History

Each exercise has a History tab: the sets from your last workout, a chart of the lift over time, and your personal bests (heaviest set, estimated one-rep max, most volume). Workout history, under the Workouts page's menu, lists every session; each one opens to the same page: the muscles it hit, its numbers, your photo if you took one, every set per exercise, and the heart-rate trace from your watch if it recorded one.

Cardio

Runs, rides, walks and the rest are logged from the same + button. Workouts your watch or another app recorded arrive through Apple Health with their routes, and routes export as GPX from Export, Manual; the full list of what the file holds is on the files page.

Your training, out of the app

• Files: the strength log as CSV or JSON, one row per working set with reps, weight, estimated 1RM and a set_type column (column definitions).
• Agents: the strength_log MCP tool returns every set with its type, per-exercise progression and volume per muscle group, warm-ups left out, on the phone, a self-hosted mirror or Connect your AI.
• Logging by AI: with Connect your AI and Allow AI write on, "log today's push session: bench 3 x 8 at 185" becomes a session in Marrow, applied by your phone and easy to undo.