STRENGTH TRAINING CALIBRATION ENGINE

Log the set.Measure the drift.Recalibrate next week.

You log weight, reps, and RIR. Calyber compares what you logged to how the set should have progressed — and recalibrates next session's prescription. No black box. Verifiable output.

Begin Calibration — FreeNo card required. Founding Member pricing available.
PLATFORM
iOS · iPad · Web
METHOD
e1RM · Banister · MGFI
CALIBRATION
Begins after 3 logged sets
FIG. 01 — SESSION IN PROGRESSPUSH A · WEEK 3/6
9:41Calyber · Push A●●●
Bench Press
Chest focus · Week 3/6
SESSION LOG
#WTREPSRIR
1145102
2145102
314510—
CHEST — WEEKLY VOLUME
MEVMAVMRV
NEXT SESSION · BENCH
3 × 8–10 @ 147.5 lbs
MEASURED e1RMSTABLE
195.8lbs
Derived from 3 sets this session · stable across 4 data points
RIR CALIBRATIONACTIVE
+0.7reps systematic bias
You underestimate RIR by 0.7 reps on average. Next prescription adjusts up.
MESOCYCLE FATIGUE (MGFI)MODERATE
0.42/ 1.0
Moderate band. Deload not triggered. Continue overload phase.
MESOCYCLE · 6 WK | EXERCISE · BENCH | SESSION · 12/18 | WEEK · 3/6

Training by feel introduces systematic error. Here is how much.

Most trained lifters misestimate RIR by 1–2 reps.

Across a mesocycle, this compounds into 10–20% unintended volume — accelerating fatigue accumulation and degrading the training stimulus before the final week.

REPORTED
MEASURED
RIR 2
Actual RIR 3.7
Volume: on plan
+12% vol drift
Deload: week 6 (scheduled)
Deload: week 4 (measured)
Session 12 · Bench Press · Week 3
DEMO · SESSION 12 OF 18
What Calyber does, across three screens.
WEEK 3 / 6 · PUSH A
01LOG
Bench Press · 3 × 8–10
#WTREPSRIR
1145102✓
2145102✓
3145102✓
INPUT · WHAT YOU DO
Three sets of bench. You log weight, reps, and your best estimate of RIR 2.
→
02MEASURE
ACTUAL EFFORT · DETECTED
54%ElevatedMGFI
FRESHMOD.ELEV.HIGH
Detected drift: RIR self-reported at 2, actual 3–4. Volume ran +12% above target.
SIGNAL · WHAT CALYBER SEES
Your logged RIR is low by 0.7 reps. The stimulus landed harder than the plan.
→
03PRESCRIBE
NEXT SESSION · AUTO-CALIBRATED
Bench Press — Session 13
LOAD
147.5 lbs
TARGET
3×8–10
RIR
3
CALIBRATION BASIS
e1RM 196 lbs · MGFI 0.42 · RIR bias corrected +0.7
OUTPUT · WHAT YOU RECEIVE
Prescription adjusts weight, rep range, and target RIR so the stimulus lands where the mesocycle plan intends.
01 · LOG
3×10 @ 145 lbs · RIR 2
02 · CALIBRATE
Drift detected: +12% vol
Actual RIR: 3–4
MGFI
68%
03 · PRESCRIBE
Next session: 148 lbs
3×8–10 · RIR 3
LIVE CALIBRATION

Adjust inputs. Watch how small errors change the prescription.

Reps
10
RIR
Estimated 1RM
203.0 lbs
Prescribed range
135.0–150.0 lbs
Correct your next mesocycle — Start free
Six terms
that do the work.
RIR
Reps in Reserve
Subjective count of reps left before failure. Trained lifters misestimate by 1–2 reps.
e1RM
Estimated 1-Rep Max
Derived from weight, reps, and RIR via Epley-form equation. Updates each set.
MESOCYCLE
Training Block
A planned 4–8 week sequence ending in a deload.
MEV·MAV·MRV
Volume Landmarks
Minimum Effective, Maximum Adaptive, Maximum Recoverable weekly set count per muscle group.
MGFI
Mesocycle Gen. Fatigue Index
Composite fatigue score normalized to 0.00–1.00. Triggers deload when sustained.
BANISTER
Fitness–Fatigue Model (1975)
Two-factor model — fitness gain minus fatigue cost — used to estimate readiness across 50+ years of literature.
TRANSPARENT LOGIC

Every output cites its inputs.

You can trace any prescribed weight back to the e1RM, fatigue score, and RIR bias used to compute it. No black box.

REACTIVE VOLUME

Volume corrects in-cycle, not next quarter.

Sets land between MEV and MRV by adjusting load and rep targets each session — not by waiting for a planned reset.

FATIGUE ARCHITECTURE

Banister with measured drift.

Fatigue model is calibrated from your logged sets, not a static template. Deload triggers on the curve you produced, not a calendar.

PROGRESSION

The algorithm gets more accurate the longer you use it.

SESSION 1
Initial e1RM estimate from logged weight, reps, and RIR. RIR bias unknown — prescription uses your reported value at face.
SESSION 3
Calibration begins. Per-lift bias is estimated; prescriptions adjust load by ±2.5 lbs to align actual effort with target RIR.
SESSION 6
RIR bias stabilized within ±0.3 reps. Mesocycle fatigue (MGFI) tracking confidence reaches operational threshold.
FIG. 02 — Compound push pattern
F: verticalLoad: 145 lbsSet 3 of 3Chest · MEV→MRVθ ≈ 90°

This is not a fitness app.

Features we deliberately excluded:

  • Motivational quotes
  • Badges and achievements
  • Social feed
  • Progress photos
  • Rounded corners
  • AI-generated coaching tips

If you want encouragement, this is not your tool. If you want to reduce estimation error, keep reading.

PRICING

Two tiers. One decision.

CALIBRATION
Free
$0 / forever
No card required.
  • Session log + e1RM tracking
  • RIR bias estimation
  • Single mesocycle template
  • iOS, iPad, Web
Begin Calibration
FOUNDING MEMBER
Practitioner
$9 / month
412 founding seats remaining
  • Full Banister + MGFI fatigue model
  • Multi-mesocycle programming
  • Reactive volume across MEV → MRV
  • Per-lift drift diagnostics + export
  • Founding price locked indefinitely
Begin Calibration — Free