Watch the engine adapt
Free interactive demo of how an adaptive workout plan rebuilds when life moves. Toggle skipped sessions, sleep, and soreness. See the per-muscle volume, stress band, and recommendations update live.
Live demo
Skip a session, drop your sleep, mark yourself sore. Watch next week's plan rebuild in real time using the same logic that runs for paying members.
Last night's sleep
Okay (7h)Soreness this morning
MildStress reads 37 of 100, and 1 muscle sits under the weekly floor
AMBER band · nothing skipped · sleep okay (7h) · mild
Muscle coverage this week
Stress
Tap a muscle to see its weekly sets against its own floor and ceiling.
Weekly sets per muscle
tick marks the floor- Chest11/16
- Upper back10/20
- Shoulders8/16
- Biceps8/16
- Triceps8/16
- Traps6/12
- Forearms8/12
- Abs6/16
- Lower back9/10
- Quads8/16
- Hamstrings10/14
- Glutes12/12
- Adductors4/10
- Calves3/16
Next week
unchanged- MonLower · squat focuswork
- TueUpper · pushwork
- WedRecovery walkrest
- ThuLower · deadlift focuswork
- FriUpper · pullwork
- SatOpen / make-up dayrest
- SunRestrest
What the engine changes
Schedule
Five sessions hold. Saturday stays as a make-up reserve, earned, not free.
Load adjust
Loads hold. Last week's RPE log is the input. Sleep is not fighting recovery.
Volume
Calves sits under the minimum effective dose. Everything else is in band.
First plan in 4 minutes.
How this works
Adaptive programming is what separates a plan that survives the first bad week from a plan that collapses. The sandbox shows the moves the engine makes when life moves: rescheduling around skipped days, adjusting loads to match recovery, and pulling volume back when recovery is the bottleneck.
The rules on this page are the rules the production engine runs. The point is to make 'adaptive' mean something specific.
Track the stress reading
Combines sleep deficit, soreness, and skipped-session count into a 0-100 stress score. Green below 33, amber 33-65, red above 65. The band drives how aggressive the load adjustments get.
Recompute weekly volume per muscle
Each skipped work session subtracts 5 sets from the muscles it targets. Heavy soreness shaves a couple of sets off lower body. The result is plotted against MEV/MAV bands so you can see who is undertrained and who is overcooked.
Reschedule or rebuild
One skip rolls into Saturday's reserve. Two or more and there is still only one open slot: the first missed session takes it, the rest do not come back this week, and the muscles that lose their volume dim on the map. The plan never tries to make you pay back missed volume by overloading the next week.
Adjust loads + volume
Low sleep takes 7 percent off top sets and a set off accessories. Strong sleep adds 2.5 percent if last week's RPE permits. Heavy soreness pulls a set off lower-body accessories and deloads the upper push. Loads hold otherwise.
The sandbox is read-only. The engine writes to your actual program every week, based on the actual data you log.
Common questions
More free tools
Why your last program died
Five honest questions. We name which of the five patterns killed your last program, and the single change we would make before you start the next one.
Diagnostic
What the algorithm sees about you
Five inputs, and you get the read the engine gets: one composite score, four subscores, the flags you tripped, and the single move worth making next.
Public scan
What's your one-rep max?
Type one working set: weight and reps. We average Epley and Brzycki, round it to the bar, and show which strength band your max lands in.
Calculator