Safety and evidence
What this programme is, and what it is not
High-intensity training has a real evidence base and a large amount of folklore attached to it. This page separates the two, and says where the programme is making a judgement call rather than following the research.
Read this first
When to stop, and when not to start
Do not start without medical clearance if you have any joint, heart or blood-pressure history, are pregnant, are recovering from surgery, or have anything that currently hurts under load. This is not a formality — the back half of this programme asks for genuine maximal effort, which raises blood pressure sharply and loads connective tissue hard.
Stop the set the moment form breaks, not when it starts to hurt. Failure is the point at which you cannot complete another rep with the same technique — it is not the point at which your back rounds to get the weight up. Those are different events and only the first one is training.
Stop the session and seek advice for sharp or joint-line pain, pain that persists after training, numbness or pins and needles, dizziness, chest pain or unusual breathlessness. The app has a pain flag on every set for exactly this, and flagged sets are excluded from your records rather than celebrated.
The central caveat
Why you cannot simply copy either man
Both men were enhanced professionals
Mentzer and Yates competed at the top of professional bodybuilding and both have been open about anabolic steroid use. Drug use changes recovery capacity, and recovery capacity is the exact variable their training arguments turn on. Their conclusions do not transfer to an unenhanced beginner unchanged, and this programme does not pretend otherwise.
The volume argument is not settled in their favour
Mentzer's strongest claim — that one set to failure produces nearly all the available growth — is not what the research on training volume generally finds. Sets close to failure clearly drive growth, and junk volume clearly wastes recovery; "the least possible work is optimal" is a further claim, and a weaker one.
Failure has a cost, and Yates paid it
Yates has said in later years that heavy forced negatives are what tore his biceps and his triceps, and that he would dial them back if he ran his career again. This programme therefore stops at momentary failure and does not prescribe forced reps.
This is not medical care
No app can examine you, and nothing here diagnoses or treats anything. Get clearance from a doctor before starting if you have any joint, heart or blood-pressure history, and stop any set the moment form breaks or anything hurts.
Evidence
What is well supported, and what is a judgement call
Each claim below is marked with how strongly it is supported, and with what kind of claim it is. Pointers are to bodies of literature rather than to invented citations.
Historical fact
Mentzer won the 1978 Mr. Universe and the 1979 Mr. Olympia heavyweight class.
supportedEnglish Wikipedia, "Mike Mentzer" ("1978 IFBB Mr. Universe – 1st"; "1979 IFBB Mr. Olympia – 2nd Overall, 1st (Heavyweight Division)") and the results tables in "1979 Mr. Olympia", where the overall went to Frank Zane. Checked August 2026. A tertiary compilation rather than the IFBB's own contest record, hence supported rather than well-supported. The widely repeated "only perfect 300 ever awarded" superlative is deliberately NOT part of this product and is not verified here.
Yates won six consecutive Mr. Olympia titles from 1992 to 1997, after placing second in 1991.
supportedEnglish Wikipedia, "Dorian Yates", placings table: 1991 2nd, 1992–1997 1st. Checked August 2026. The 1991 placing is why the product does not say he retired undefeated.
Yates attributes his biceps and triceps tears to heavy forced negatives, and has discussed steroid use.
first partyYates's own published interviews and autobiography. Stated by him, not inferred. The years — biceps in 1994, triceps three weeks before the 1997 Olympia — are corroborated by the Wikipedia article and by his 1997 interviews.
Both men competed as professionals and both have been open about anabolic steroid use.
first partyStated by both men in published interviews. It matters here because recovery capacity is the exact variable their training arguments turn on.
Coaching interpretation
More hard sets per muscle per week produce more growth, up to a point.
well supportedMeta-analyses of resistance-training volume and hypertrophy — search "resistance training volume dose-response hypertrophy meta-analysis". Multiple independent analyses report a dose-response relationship. Where the curve flattens varies between analyses and between people, which is why the copy gives a region rather than a number.
Sets taken close to failure drive hypertrophy; sets stopped well short do less.
well supportedLiterature on proximity to failure and reps in reserve in hypertrophy training.
Untrained lifters asked to stop one rep short routinely stop with four or more left.
supportedStudies comparing self-reported reps in reserve against measured repetitions to failure in untrained participants.
Tendon and connective tissue adapt more slowly than muscle.
supportedTendon adaptation and collagen turnover literature in response to resistance training.
Several lifts stalling at once is more often a recovery problem than a programming one.
conventionBoth men's central argument, and standard coaching practice. It is an interpretation of a pattern in a logbook rather than a finding: nobody has measured how often a simultaneous stall is recovery and how often it is something else.
Practical guidance
Strength holds for roughly a fortnight away from training, then declines; the tolerance for a hard set goes sooner.
conventionDetraining literature gives the direction — strength is retained longer than most people expect, and the loss accelerates with time away — but the day counts the app bands on (14, 28, 56) are coaching convention, not measured thresholds. They are set where the advice changes, not where the body does.
A week at about 60% of usual loads, stopped well short of failure, sheds accumulated fatigue without losing the pattern.
conventionStandard coaching practice. The specific numbers are chosen to be unambiguously easy rather than optimal — a deload a lifter can talk themselves out of is not a deload — and there is no literature naming 60% as a correct figure.
A movement can be swapped for another that trains the same primary muscle without changing what the session does.
conventionCoaching convention, and the same list the app already offers a lifter choosing a substitute by hand. It is a claim about equivalence of muscle worked, not of stimulus — a goblet squat and a leg press are not the same exercise, and the app says which one it swapped and why.
Contested
Low-effort sets buy less growth per unit of recovery than hard ones.
supportedFollows from the proximity-to-failure literature rather than being measured directly. "Buys nothing at all" is the stronger claim and is not established — low-effort sets do contribute, less efficiently.
One hard set produces real growth, but not as much as several.
well supportedThe same volume meta-analyses. This is the specific point where Mentzer's strongest claim and the research part company, and the product presents it as a time-for-growth trade rather than as a settled question.
Pre-exhausting a muscle makes the following compound lift work the target harder.
first partyMentzer's stated rationale. Studies of pre-exhaustion have not consistently shown greater target-muscle activation or growth, so the product presents it as his argument rather than as a mechanism.
Restricted shoulder rotation is associated with pain when pressing volume is high.
supportedThe association is reported; the mechanical "impingement" explanation for it is disputed in the current shoulder-pain literature. The screen is kept because the association is enough to justify checking, and the copy no longer asserts the mechanism.
The movement screen
How safety is enforced rather than suggested
Six tests, before load. If one fails, the programme changes — a warning you can ignore is not a safeguard.
Ankle — knee to wall
Restricted ankles are a common reason a squat won't reach depth without the heels rising.
Squat depth
This is the pattern half your lower-body work is built on. It needs to be automatic before load goes on it.
Hip hinge
Every row, deadlift and RDL rides on this. Lose it under load and the lower back takes the work.
Overhead reach
If the shoulders can't get overhead, the lower back arches to fake it. That's how pressing turns into a back problem.
Shoulder rotation
Limited rotation here often goes together with shoulder pain in people who press a lot. Exactly why is still argued over, but it is worth knowing about before you add pressing volume.
Thoracic rotation
A stiff upper back forces the lower back and shoulders to compensate on rows and presses.
Limitations
What this product cannot do
- It cannot watch your technique. A coach can, and for a true beginner that is worth more than any app.
- Your data lives in one browser on one machine. Exporting is manual, and if you clear your site data without a backup it is gone.
- The starting loads are estimates from a formula. Expect to correct them on the day, particularly in the first fortnight.
- The energy targets carry roughly ±10% of built-in error before individual variation. The scale corrects them, not the equation.
The Ledger is an educational and record-keeping tool. It does not diagnose, treat or manage any condition, and it is not a substitute for a physiotherapist, a doctor or a coach who can watch you move.
All twenty-four weeks are free
The movement screen, the baseline tests, and twenty-four weeks of programmed sessions. No card, no account, nothing held back. The first session is calibration rather than training.