How Hank built his lifting and HIIT app
The short version
Hank used Grok Bot to build a personalized lifting and HIIT app from his own workout history. A Workout assistant led the way, with help from a Health Coach and an App Developer assistant.
The app covers a 3-day A/B/C lifting split, HIIT with live heart rate from a chest strap, a 12-week rotation with deload weeks, a Galaxy Watch companion, and sleep and readiness from Health Connect. The tour below walks through it.
Where it started
Three starting points: years of Hank's Excel workout history, a program from the Workout and Health Coach assistants, and Hank's own goals. None of it is required, though. Anyone can start from scratch.
The build loop
Hank gives requirements, the App Developer builds, Hank tests and gives more feedback, the App Developer keeps building, and then the loop starts again.
The tour
Lifting three days a week, HIIT twice
Three weekly lifting workouts (Days A, B and C), with HIIT on the treadmill twice a week on top.
A HIIT round in progress. Inside the app
Today 
HIIT 
Workout 
Settings A music panel that slides out
On wide screens a music panel tucks away at the side and slides out to show what's playing.
Collapsed 
Expanded Timers
Rest timer: flashes on the phone when rest ends. HIIT interval timer: sprint and recover rounds. The watch companion
The idea came up mid-HIIT on the treadmill: Hank wanted to start and stop HIIT from his wrist without touching the phone. The watch app starts and stops HIIT, shows sprint and recover with a buzz at each change, shows heart rate (the H10 via the phone, with the watch sensor as backup), and logs lifting sets with a rest timer that buzzes at 10 seconds left and again when rest ends.
Home 
Sprint 
Lifting set 
Rest Watch images are preview mockups. Status as of Oct 22, 2026: version 1.1 is built and ready to install on Hank's Galaxy Watch 8 Ultra. Testing on the watch is next, and the live H10 heart-rate relay comes with the next phone update.
All the features Hank picked
ABuilt by a teamHealth Coach and Workout plan it, App Developer builds it, Hank approves.
History starterStarts from years of workout history, or from scratch.
Excel tracker backboneAn Excel tracker is the backbone; the app exports to it.
3-day programA 3-day A/B/C lifting split plus HIIT days.
Chest-strap heart rateLive heart rate from a Polar H10, with the watch as backup.
HIIT resultsSplits, average and peak heart rate, and recovery each round.HEstimated caloriesCalories estimated from heart rate.
Weight changesChange weights any time.LTarget suggestionsWorkout suggests a new target; Hank accepts or dismisses it.
Tips and belt notesCoaching tips and belt advice on every exercise.
Details sectionPer-exercise details that reopen each new day.
Rule-check notesSafety notes, like taking it easy on broth-fast days.
Rest timerThe phone flashes when rest ends; the watch buzzes at 10 seconds left and at the end.
12-week rotationAccessory exercises rotate between blocks.RDeloadsDeload weeks built in.SPer-block swapsSwap an exercise for the block, like pushdowns for lying tricep extensions.
Music panelShows what's playing, right in the app.
Web versionWorks in a browser too.
Galaxy WatchA watch companion app.
SyncSyncs across devices.ZHealth ConnectSleep and daily readiness from Health Connect.
Narration transcript
This is the story of how Hank built his own workout app without writing any code, just by talking to a team of Grok Bot assistants. A Health Coach and a Workout assistant set his goals and wrote the program. An App Developer assistant built the app. Hank gave feedback by chat and by voice. Each new version showed up as screenshots first, and nothing went onto his Samsung phone until he said yes. That loop has run twenty-eight times so far. It started from years of his old workout spreadsheets, but anyone could just as easily start from scratch.
Here's what it does. There's a three-day lifting program with HIIT days on the treadmill in between. During HIIT the app switches Hank between sprint and recover, showing his heart rate live from a Polar chest strap. Afterward he sees his splits, how fast his heart rate recovered, and estimated calories. The weights move through a twelve-week cycle with deload weeks, accessory exercises rotate between blocks, and the coach can suggest new targets that Hank accepts or skips. There's a rest timer, a music panel, and sleep data from Health Connect.
Then, in the middle of a treadmill session, a new idea came up: running HIIT from his wrist. So the team built a Galaxy Watch companion. It starts and stops HIIT, buzzes at each sprint and recover, shows his heart rate, and logs lifting sets with a rest timer. Version 1.1 is built. Next up is testing it on his wrist.
Audio version coming once a voice is picked.
Screenshots are real app screens with numbers blurred.