METHODOLOGY · §1.0

The five-stage calibration loop.

Calyber prescribes, measures, and recalibrates across every session using a deterministic five-stage loop. Each prescription shows its basis: the weight, reps, and RIR used to compute the next target.

Last calibrated: 2026-05-08

Begin Calibration, Free

01PRESCRIBE

Compute target weight and rep range from prior e1RM using the Epley formula.

02EXECUTE

Log actual weight, reps, and RIR for each set.

03MEASURE

Compute new e1RM from completed sets.

04CALIBRATE

Compare to baseline. Apply autoregulation: load adjust, volume adjust, or recovery trigger.

05RE-PRESCRIBE

Generate next session's prescription from calibrated e1RM.

§2 · Worked example.

Session W3D1 · Bench Press (Barbell)
Prescription:  3×8-12 @ RIR 2  ·  Target 145 lbs
Actual:        3×10 @ RIR 2    ·  145 lbs
e1RM:          145 × (1 + 10/36) = 185 lbs
Next target:   Calibrate → 150 lbs  ·  8-12 reps @ RIR 1
Basis:         +3.4% load · within MAV · no recovery flag

§3 · Volume landmarks.

LANDMARK	DEFINITION	TRIGGER
MEV	Minimum Effective Volume: least volume that produces adaptation	Floor for prescription
MAV	Maximum Adaptive Volume: volume at which adaptation is maximised	Target prescription range
MRV	Maximum Recoverable Volume: volume beyond which recovery fails	Deload or volume cut trigger

Schoenfeld, B.J. (2017). Science and Development of Muscle Hypertrophy. doi:10.1519/JSC.0000000000001817

§4 · Fatigue index (MGFI).

Each muscle group carries a Muscle Group Fatigue Index (MGFI) computed from pump rating, soreness rating, and session performance. MGFI gates deload, recovery, and volume adjustments. See the algorithm breakdown for the full formula.

Fatigue Index algorithm →

§5 · Autoregulation.

Three pipelines run after each session: load adjustment, volume adjustment, and recovery trigger. Each pipeline has a decision threshold derived from the MGFI and e1RM delta.

See /algorithm/autoregulation

§6 · What this is not.

Not an AI. Every prescription is a deterministic formula with visible inputs and outputs.
Not a coach replacement. Calyber does not interpret form, injury risk, or subjective readiness.
Not personalized in the marketing sense. The system does not know your goals beyond the rep-range and priority settings you configure.

§ Citations