On every session, Calyber runs a five-stage calibration loop: it reads the weight, reps, and effort you logged, computes your next prescription, and shows the reason behind it.
Free to start, no card required. Your 28-day calibration block adjusts from your first logged set.
Basis: Effort matched target. Recovery within range. Load +5 lb.
§1 · The lifters
What to lift, how many reps, and how hard each set should feel. No formulas to learn first.
See the loopWhen to add load, reps, or volume, based on what your last sessions actually produced.
See a worked exampleEvery input behind a prescription: prior performance, RIR, e1RM, volume range, and recovery status.
See the volume model§2 · Worked example
One exercise, one session, the full cause and effect chain. This is the actual logic, not a marketing summary.
e1RM rose, effort matched the target, and no recovery flag fired.
Terms:
§3 · The loop
Calyber repeats the same five steps on every set you log. The output of one session becomes the input to the next.
Terms:
Calyber sets your target weight, rep range, and effort for the session.
145 lbs · 8-12 reps · RIR 2You log the actual weight, reps, and reps in reserve for each set.
145 lbs × 10 · RIR 2Calyber computes a fresh strength estimate from the sets you completed.
e1RM 193 lbsIt compares the result to your baseline and checks fatigue, then adjusts load, volume, or recovery.
+3.4% · within MAVThe next session's target is generated from the calibrated estimate.
150 lbs · RIR 1Step 05 feeds back into step 01
§4 · On-screen logic
Every step of the loop has a surface in the app. Each one shows the reason behind the number.
§5 · Volume
More volume is not better forever. Growth comes from enough stress plus enough recovery. Calyber keeps your weekly sets inside the productive zone and pulls back before recovery fails.
Your prescription: Calyber keeps your weekly sets inside the MAV zone.
Schoenfeld, B.J. (2021). Science and Development of Muscle Hypertrophy (2nd ed.). Human Kinetics.
§6 · Fatigue index
Each muscle group carries a Muscle Group Fatigue Index, computed from pump rating, soreness rating, and session performance. MGFI gates deload, recovery, and volume adjustments.
Terms:
readiness = (performance × 0.6) + (soreness × 0.4)
accumulation = (sets × 0.5) + (soreness × 0.3) + (workload × 0.2)
MGFI gates deload, recovery, and volume adjustments per muscle group.
§7 · 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 the e1RM delta.
e1RM rose, fatigue normal: load increased
Terms:
§8 · Trust
Every prescription shows its inputs: load, reps, RIR, e1RM, volume range, and recovery status.
Calyber does not add volume when fatigue is already high. It reduces load or triggers a recovery session instead.
Targets sit inside research-backed volume landmarks (MEV, MAV, MRV), not generic activity goals.
You can see why a prescription changed before you follow it. Nothing is hidden.
§9 · Boundaries
Every prescription is a deterministic formula with visible inputs and outputs, not a prediction.
It does not interpret form, injury risk, or subjective readiness.
The system knows your goals only through the rep-range and priority settings you configure.
No card required. Your first block calibrates to your real performance from the first set.
FAQ
It is the cycle Calyber runs on every session: prescribe a target, you execute and log it, Calyber measures a fresh strength estimate, calibrates against your baseline and fatigue, then re-prescribes the next session. Each step is visible and traces back to your logged sets.
No. Calyber tells you what to lift, how many reps, and how hard each set should feel. The formulas are there if you want to check them, but you do not have to learn anything first.
A fixed program runs the same plan regardless of how your sessions go. Calyber adjusts your next session from what you actually logged: it adds load when you progress, holds when you stall, and reduces volume or triggers recovery when fatigue is high.
No. It does not interpret form, injury risk, or subjective readiness. It calculates load, volume, and recovery decisions from your logged training data and shows the reason behind each one.
References
Schoenfeld, B.J. (2021). Science and Development of Muscle Hypertrophy (2nd ed.). Human Kinetics.
Helms, E.R., Fitschen, P.J., Aragon, A.A., Cronin, J., Schoenfeld, B.J. (2015). Recommendations for natural bodybuilding contest preparation: resistance and cardiovascular training. J Sports Med Phys Fitness, 55(3), 164-178.
Epley, B. (1985). Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises.