Seven rules. Each one cited. Each one graded.

Most of the strength and health benefit of resistance training arrives inside roughly two hours a week. Beyond that the curve flattens; below it, it falls fast. Your days times your minutes are checked against the band, not against an ideal.

The bad-week banner in onboarding tells you which side of the band you're on. The plan never asks for more than the band.

BJSM 2026 · Momma et al. 2022

Set time estimate plus prescribed rest plus transitions is at most your window, tolerance −2/+0 minutes. Change the window and the session is rebuilt from the same seed. Actual elapsed time feeds a per-member pace factor.

The window stepper on Today. "Built for 23 min" in every session card.

Planned-duration invariant

Two consecutive sessions at the top of the rep range with RPE at or below 8 trigger a step. Your push setting sets the size: +2.5%, +5%, or +7.5% upper / +10% lower. Tendon-loaded patterns cap at +5%. Two stalls hold or drop 5%. Never to failure; two reps in reserve is the floor. Reported reps-in-reserve are treated as under-counted by one.

Log a set with RPE. Profile → How hard to push.

Halperin et al. · Helms et al. · Zourdos et al.

Short sleep or low energy eases load by 5 to 10% and drops one movement. A sore muscle group routes the pattern around it for the session, and for two weeks if it repeats. The comparison is to your own rolling baseline, never a population norm, and never a rest-day prescription.

Check in · 3 taps on Today, then the eased session.

Saw et al. 2016 · Craven et al. 2022

Up to seven days away changes nothing. Eight to 21 days: 5 to 10% lighter, one more rep in reserve, one session. 22 to 56 days: about 40% in week one, ramped over half the gap. Longer: re-onboard at 50 to 65%. The return week never asks for more than one fewer session than your bad week, and no load after a gap exceeds the last one you logged.

Welcome back → What changed this week.

Comeback ladder · Bickel et al. 2011

One hard set per pattern, once or twice a week, with load held and two to three reps in reserve maintains strength for up to eight weeks. Then a two-week ramp back at two thirds volume.

Profile → Life mode. A 1 to 8 week stepper and a four-row contract.

Spiering et al. 2021 · Bickel et al. 2011

The substitution ladder runs lighter, slower tempo, shorter range, different implement, different exercise in the same pattern. Pattern coverage holds through every swap. Sharp or radiating stops the movement, rests the pattern for two weeks, and exits to "see a professional". There is no pain scale and the word injury does not appear in the app.

The comfort sheet during any set.

Substitution ladder · coverage invariant