Strength coaching for iPhone
He changes your workout in the middle of it.
You are still breathing hard from the last set when he writes the next one. You see the remaining sets cut when you fade, the plate added the day you earn it, and what he expected from you written down before you touched the bar.
In testing on iPhone, not on the App Store yet. There is no waiting list: you write to a person and a person writes back.
Predicted range?
Example, not a screenshot.
What he actually does
He decides, then he reacts.
A logbook remembers. A plan hands you a program and stops listening. Jerry picks the lift, sets the load, and then changes the rest of the session the moment what you report after each set tells him the day is not going the way he thought.
He holds the load, asks for one more rep, and adds the plate once you have earned it.
55 kg · 12 reps · RIR 5, with the warm-up and the plates for the bar laid out under it, and the reason is written at the bottom: 15 kg lighter than last time, on purpose: it is a recovery week.
Recovery week. I am not raising this weight on purpose. The set came in above what his model of the lift expected, and he says so, and he says he moves his estimate over your next sessions rather than in one jump. The rest was 90s.Day one against day one hundred
We have not found a coaching app that is less certain on your first session than on your hundredth.
Only one of the two below ever changes.
Every app promises to personalise your training from the first session, as though it had met you. On day one it has your age, your sex and your weight: a population average wearing your name. A body takes evidence to know, so Jerry shows you what he actually sees before he tells you what to do, and becomes yours as your own sets accumulate. A mirror first and a coach second, and that order is the product.
A typical coaching app
Your one rep max is 137 kg.
No basis shown. No confidence stated. No way to check it.
unchanged since session 1
Jerry
I do not know you yet. Until your own sets exist I start from population averages for your age, sex and bodyweight, and I say so every time I do.
Basis: population research. Nothing here is a claim about your body. It becomes one only when your own sets say so.
Population
The slider is a session count because that is the only dial a web page can offer you. Inside the app the pace runs on evidence: sessions with a lot of real working sets move it faster than the calendar does, and it moves back if his predictions start missing. A few of the deeper reads also hold a hard floor, and those are named on how it works.
Not a mockup
This is the actual screen. Read what it admits.
A real screenshot of the app on a clean install, after one logged session. Nothing retouched, nothing staged.
-
01
It tells you it is still learning
The badge reads
Building, not a confidence score invented to look reassuring. One session is not enough to know you and the screen says so. -
02
Every number carries where it came from
Fatigue and recovery are marked
Estimate: a population estimate until your own data replaces it. They are not claims about your body, and they are not allowed to pretend to be. -
03
Evidence moves it, and some of it holds a floor
The app's own line, on the screen: what he can tell you
opens on evidence, not on time. True of the pace. Not true of everything: three of the deepest readings wait for fifteen sessions' worth of evidence, and a session only counts towards that twice a day and ten times a week at most, so the fastest honest path opens them on your eighth training day across two weeks. Below that the sample is too small to mean anything. Both halves are here because only one flatters us.
A screenshot of the app as it ships, on an iPhone with nothing else on it.
The seal
Try to make him look better than he was.
A sealed prediction in the exact shape the app produces, field for field. Widen the range so he looks right, or change the lift. The fingerprint recomputes in your browser as you type.
Fingerprint, recomputed in your browsermatches the seal
28168c46d4cffa65957c2d3bd3f6494fbf2ac1933a67248bd1c5a51d2db46915
What is actually sealed
These are the exact fields the app seals, in the exact form it seals them, which is why the fingerprint below can be checked at all. The weights are written as whole numbers so that no rounding can creep in: 1025000 is 102.5 kg. The last line is the date, counted in seconds.
scheme os-commit-v1-sha256 sealed 28168c46d4cffa65957c2d3bd3f6494fbf2ac1933a67248bd1c5a51d2db46915 nonce 412cabcd699f0a2a4cc22cfa1871753bd48789a2cc736aa97b517da656d5aec6 field kind = session-forecast field exercise = Barbell Back Squat field bandLowKg = 1025000 field bandHighKg = 1125000 field naiveBaselineKg = 1000000 field sealedFor = 1755916800
Nothing you change here leaves your browser. The arithmetic ran on your machine.
Checking this page’s arithmetic against our own server, so you can see the two agree.
That arithmetic just ran on your machine, not ours. Every session forecast is sealed this way before the set, and so are his longer calls: the month ahead he commits to, and anything he decides to test on you, are both written down and sealed before they start rather than explained afterwards.
Where the category stops
Four kinds of app. One shared habit.
They ask you a question, then ignore the answer.
The pressure test
Three things most apps never show you.
The same screen on day one and after a hundred logged sessions, and the sheet behind it. Each one admits something. Real screenshots of the app, nothing retouched.
10% and recovery 92%, both stamped Estimate, which is a population estimate until your own data replaces it. The middle ring says Calibration (Building) and shows no number, because one session is not calibration. The strongest thing on record is a Barbell Back Squat at Estimated 1RM 56.3 kg, which is what a beginner's first weeks actually weigh.
You are about 67% ready today, from your own sets and population averages. The strongest thing on record is a Barbell Back Squat at Estimated 1RM 129.2 kg, and the middle ring has filled: 81%, stamped Calibration (Your RIR). Read that one carefully, because it is narrower than it looks. It scores how consistently you report your own effort, not how well Jerry knows you, and this demonstration athlete reports his effort with a regularity no human has. A human is less tidy and will sit lower. Fatigue and recovery are still stamped Estimate.
Trust Intelligence, marked Population. Its own line says it: Each one names the evidence I still need. Then it does, by name: a first repeated-load comparison, Metabolic Phenotype, Individual Recovery Fingerprint, and what would close each.Every one of these is a screenshot of the app as it ships. The hundred-session athlete is a demonstration account, not a customer. If a number here ever stops matching the app, the screenshot is the thing that is wrong.
I am Jeremiah, and I built this.
Every coaching app I have paid for was certain about me on the first day, and not one of them ever came back and told me it had been wrong. That is the whole reason this one writes its guess down before you lift and then grades itself where you can read it.
I am one person and a small test group, not a company with a support desk. If you write to [email protected], I am who answers.
The commitment
The accuracy record is published before we charge anyone.
Published once the number looks good, it is marketing. Published first, it is a commitment.
Free, and it stays free
Every day, whether or not you pay
- Logging every set, and sessions you put together yourself
- Your daily fatigue, recovery and readiness readings
- Your training history in the app, and Jerry's spoken voice
- The accuracy record, including every call he got wrong
- Every warning: a stalled lift, a week that has to be lighter, a recovery that will not carry what you planned
- An injury question answered in full, and your own words quoted back with the date you said them
Pro
After your first 28 days, coached in full, free
- His prescribed sessions
- His coaching answers in chat
- The deeper analysis screens
- From the first day: your complete history export, a second imported log, and the weekly report as a file
199 US dollars a year · about 16.58 a monthor 29.99 a month, stop whenever you like · US price, set country by country, Apple shows you yours first
The whole contract, in plain words
Jerry coaches you in full for your first 28 days, without asking for a credit card: he builds the session, sets the weight, warms you up to it, and changes his mind while you are still in it. After those 28 days his prescribed sessions, the coaching answers he gives you in chat, and the deeper analysis screens are what Pro keeps open. Pro also carries three things that are paid from the first day and are not part of that window: your complete history export back to the first set, importing another training log after the first one, and the weekly report as a file you can send. Logging, sessions you put together yourself, your daily fatigue, recovery and readiness readings, your training history in the app, Jerry's spoken voice and the accuracy record including every call he got wrong are free and stay free. So is a straight answer about safety: ask him what more work would do to you and he tells you when it would take you past the limit he refuses to cross, whether or not you pay. What he does not show you then is the measurement behind it. No warning is ever behind the paywall: when a lift has stalled, when the week has to be lighter, when your recovery will not carry what you planned, he says so whether or not you pay, because withholding those changes what your body does that week. What he will not do for free is tell you what to do about it: under each of those warnings, where his answer would be, it says to open Pro. You are always told that something is wrong. Pro is what opens what he would do. Two more never move behind it either: he answers an injury question in full, with your own record and the load he has already taken off you, and his notebook quotes your own words back to you with the date you said them.
A human strength coach costs 200 to 600 US dollars a month. Barbell Logic is 199 a month, Future 199 a month, Reactive Training Systems 220, Juggernaut's one to one coaching starts at 297, and Renaissance Periodization runs 350 to 600. This is 199 dollars for a whole year, which works out at about 16.58 a month, or 29.99 a month if you would rather pay monthly and stop whenever you like. That is the United States price. It is set country by country and is lower nearly everywhere else: 99.99 a year in Argentina, 169 euros in Spain. Apple shows you yours before you pay anything. Which price you get follows the country of your Apple account rather than where you live. It renews until you cancel it, you cancel it in your own Apple settings, and the accuracy record is published before anyone is charged. The terms say the rest in the same plain words.
Not on the App Store yet, and there is no mailing tool: your address would sit in one inbox, read by one person, and go nowhere else. That button opens an email you do not have to write. If it does nothing on your machine, the address is [email protected] and one line is plenty.