DELTA
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DELTA INSTRUMENT · FIG. 01SCALE 1 : 1 · ILLUSTRATIVE LOG
DELTA · IPHONE + APPLE WATCH
A logbook that tells you the truth.
Delta is an instrument for people who train seriously. It reads your recovery, remembers every lift, and tells you, without flattery, whether you're actually getting stronger.
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THE PROBLEM
Trackers flatter.
Logbooks forget.
A log records 185 × 8. The question a lifter actually has is whether that beat last time, and whether it beat it at a comparable load.
An all-time PR list never expires. A lifter back from a layoff sees numbers set eighteen months ago and cannot tell what they have actually got back.
Delta splits it: 4 of 11 past the pre-break best, 7 still re-establishing, side by side, never averaged into a flattering number.
RECOVERY
Readings,
not opinions.
Any app can promise it won't flatter you. Recovery is the evidence: resting HR, sleep, HRV, respiratory rate and wrist temp from last night, scored against your own baseline: 50 is your normal.
Computed once, fixed for the day: an afternoon workout can't retroactively move the morning's score. Soreness is entered by hand, because no sensor knows it.
Logging apps don't read your night. Recovery wearables don't know what you lifted. Delta holds both.
CLICK THE RECOVERY CARD →
THE LOGGER
Phone in the bag.
Watch on the wrist.
Start a session and the watch takes over, one set at a time: the load to put on the bar, what last time looked like, one tap to log. Last time's sets are the target; the counter tracks today's.
BELOW: THE WATCH AT REST, THEN MID-SESSION
01 · TRAINING INTELLIGENCE
History becomes the target.
Every exercise carries a LAST line: what you did last time, sitting above the sets you're about to do. The session isn't a blank form; it's a number to beat.
Progression is chosen per exercise, as a module, and each method changes how the logger behaves and how progress is measured. Myo-reps get their own model: an activation set to about one rep short, then mini-sets of three to five, pushing the session total past last time. Top out, add load. A log that takes myo-reps as free text measures progress as though every set were straight; Delta models the method, and the measure follows it.
Incline Press STRAIGHT · 3 SETS
LAST 155×10 · 155×10 · 155×10 · 155×7 · ★ PR
Straight Top / back-off Drop Myo-reps Rest-pause
Myo-reps in one line: 42.5 lb · activation 15 · minis 4·4·4·3 = total 30. Next session, beat 30.
02 · TRAIN
The next session is already loaded.
Your program's days sit next-up on top, last-done at the bottom. Drag to reorder, or log an off-program session. Pick from 4-Day Upper/Lower, 3-Day Full Body, Push/Pull/Legs, 2-Day Upper/Lower, or build your own, or import a shared program from a code with a preview before you run it.
Switching programs never loses your numbers.
Upper ANEXT UP8 exercises · 3 myo
6 days ago
Lower A
5 exercises · 2 myo
5 days ago
Upper B
7 exercises · 3 myo
3 days ago
Rename days, reorder exercises, set a backup per lift, choose the method, set the rest: all in the day editor.
03 · EXECUTION
Effort goes on the record.
Sets are logged at one to two reps in reserve, the program's target, or marked as taken to failure. Rest timers adjust per exercise. A lift can be held at maintenance without breaking the record. And when the machine's taken, the backup you pre-chose is one tap away.
Discard a bad day without ceremony. Finish and the Coach reads the session before you've racked the plates.
1 lb155 reps10
+ add set ⏱ Rest 2:00+
⇄ Machine taken? Use DB Press
○ Mark as maintenance / hold
04 · EXERCISE SELECTION
The right lift, not just a lift.
The picker filters by equipment and body part, and custom exercises are first-class. The catalogue reconciles every lift you've ever logged, so history never splits across two names for the same movement.
There's a joint-friendly filter, too, for lifters training around what the years left behind.
Barbell Dumbbell Machine Cable Bodyweight Joint-friendly
Belt SquatMACHINE · QUADS
Machine Chest PressMACHINE · CHEST
+ Create a custom exercise
05 · SESSION HISTORY
History follows the lift.
Rename a lift, switch to the machine variant, or change programs, and a conventional log starts a fresh record. Years of lineage quietly fork. Delta reconciles the catalogue instead: every saved session keeps its date, exercises, duration and PRs, and per-lift history follows the lift. Switch programs and every number comes with you.
Lower B
Aug 21 · 2:14 PM · 6 exercises · 48:32 · 2 PRs
Upper B
Aug 20 · 6:05 AM · 7 exercises · 55:10
Upper A
Aug 17 · 6:12 AM · 8 exercises · 58:41 · 2 PRs
From the same illustrative log as everything else on this page.
06 · PROGRESS
Beating the logbook is the only streak.
Not sessions completed. A streak measures attendance, not strength. Delta counts the proportion of lifts you trained recently that set a new best. Weekly volume by muscle is counted in hard sets against a hypertrophy landmark, with the counting rules for myo-reps and drop sets stated, and an honest note that muscle mapping is approximate.
A readiness-driven lighter week counts as on-plan, not a miss.
4 of 11
lifts with a pre-break best are past it; 7 still re-establishing
Avg +27.6% across all 15 loaded lifts since this athlete started Delta · 82 times the logbook was beaten · 24 movements trained
On plan 7 of the last 8 weeks. The lighter week was readiness-driven and counted as on-plan.
Belt Squat≈ 238 lb · 8 sessions+98.3%
Seated Cable Rows≈ 256 lb · 15 sessions+50.9%
Leg Press≈ 173 lb · 5 sessions+37.6%
Estimated 1RM, biggest movers first, since this athlete started Delta. One illustrative log.
07 · RECAP
A summary that refuses to flatter.
Eight weeks of real work in one card: sessions, the share of lifts beating the logbook, the recovery week you took on purpose. Deliberately unglamorous, built to screenshot. No confetti, no chased PRs.
DELTA · LAST 8 WEEKS
4 of 11 lifts past your pre-break best
31
sessions
60%
of lifts beat the logbook
82
times you beat your last
1
recovery week, on purpose
Biggest mover: Belt Squat +98.3%
No streaks. No vanity PRs. Just steady, honest work.
08 · BODY
Strength leads. Composition lags.
PRs are the leading signal that training is working; body composition is the lagging proof it's becoming muscle. A single scan swings with hydration. Read the line, not the dot. Add scans by hand, import CSV, or sync from Health.
Weight194.7 lb▲ 1.1 lb/wk
Body Fat18.4 %▼ 0.0 %/wk
Lean Mass142.2 lb▼ 0.5 lb/wk
28-day trend: weight up, lean mass down, fat flat. The scale is moving and the composition isn't. Delta says so instead of calling it a bulk.
09 · COACH
It reads your data, then makes a call.
Not a chatbot with a gym vocabulary: an exchange grounded in your own numbers. Here is a real answer, at full length.
Should I push or deload this week?
Your readiness is at 47, below your baseline of 50, and you're reporting soreness at a 3, well above your usual 1. The drivers: sleep came in short (6.3h vs your 7.3h average), resting HR is actually good, but HRV, wrist temp, and respiratory rate are all drifting off your normal. Mixed picture; the soreness signal is the loudest one here. On the other side, you're beating the logbook at a 60% rate over the last two weeks, strong progress, and you haven't taken a lighter week in 8 weeks. That's the real tell: you're accumulating work without a break to consolidate it. Deload this week. Not because you're broken; a lighter 4–5 days now lets you come back harder and actually cash in the momentum. Drop volume ~30–40%, drop loads slightly, keep the movements the same.
Watch-list a lift Post-session observations Injury-driven substitutions After sessions · before & after · off
An optional profile shapes advice only; it never enters any number.
10 · DAY ONE
EXTENSION · DESIGNED, NOT YET IN THE APP
What an empty logbook looks like.
No history to import, no baseline yet. Delta starts quiet and earns its numbers.
READINESS
No baseline yet
Delta learns your normal over the first week or two of nights. Until then, it says so instead of guessing.
PROGRESS
Nothing to beat yet
Your first session becomes the line every later session has to pass. The logbook starts honest at zero.
TRAIN
Pick a program
4-Day Upper/Lower is loaded to start. Change it, build your own, or import one. Your numbers follow the lifts either way.
DELTA INSTRUMENT · FIG. 02 · LIVE UNIT
Try Delta
The interface below is the real one. Your cursor is the finger: open Upper A and the watch wakes as the logger. Check Progress, ask the Coach. Hover for the guided notes.
SCROLL UNTIL IT DOCKS
HEALTH PERMISSIONS, PURCHASES AND
WATCH PAIRING ARE NATIVE-ONLY.
EVERYTHING ELSE IS LIVE
11 · PRINCIPLES
Quiet about everything except the truth.
YOUR DATAOn-device, included in iCloud device backups, exportable as JSON. Restore it anywhere.
TRAINERSLink with a code, see exactly what a trainer receives before anything is shared, end it any time. Body data never reaches a trainer, whatever the settings say. The readiness score, and the signals behind it, never leave the athlete's phone.
HEALTHDelta reads what you grant and says plainly what it can't see: iOS's own permission switches belong to iOS.
NO THEATERNo streaks, no confetti, no dark patterns around progress. A number appears when it's earned.
12 · GET DELTA
Train like it's measured.
Delta is in private testing on iPhone and Apple Watch.
Request early access
IPHONE + APPLE WATCH · COACH IS OPTIONAL
DELTAAll figures shown are one athlete's illustrative log, not a promised result.For trainersBack to top ↑
RECOVERY
Steady Around your baseline: a normal training day. Train as planned; how far you push is how the session feels.
47
PROGRESS
4 of 11 lifts with a pre-break best are past it; 7 still re-establishing Avg +27.6% across all 15 loaded lifts since you started Delta Per-lift breakdown ›
NEXT UP
Upper ANEXT UP 8 exercises · 3 myo
6 days ago