@sculpt-ai/progressive-overload

Progressive overload & 1RM prescription engine — the math behind Sculpt AI's workout generation.

A pure, zero-dependency TypeScript module that turns a logged working set (weight × reps, optional RIR) into an updated one-rep-max estimate and the next prescribed working weight. It covers RPE/RIR percentage tables, Epley/Brzycki 1RM estimation, outlier containment, miss-streak readiness easing, and goal-based rep/percent targets (strength / hypertrophy / endurance).

Install

npm i @sculpt-ai/progressive-overload

Usage

import { setE1RM, nextPrescription, PrescriptionInput } from '@sculpt-ai/progressive-overload';

// Estimate a one-rep max from a working set (weight, reps, RIR).
const e1rm = setE1RM(100, 8, 2); // ≈ 135.3 (kg in, kg out)

// Given the last logged set, get the next prescription.
const input: PrescriptionInput = {
  progressionType: 'LoadRep',
  pr1RM: 135,
  capacity1RM: 135,
  prescribedWeight: 100,
  goal: 'HYPERTROPHY',
  roundIncrement: 2.5,
  displayUnit: 'metric',
  best: { weight: 100, reps: 10 },
  rir: 2,
  missStreak: 0,
};

const result = nextPrescription(input);
// result.action === 'NEW_PR'
// result.capacity1RM ≈ 147.1
// result.prescribedWeight  → next working weight, rounded to the display unit

All weights are in kilograms; displayUnit: 'imperial' only affects the rounding of prescribedWeight (to a clean lb plate, stored back in kg).

For batched calls (multiple exercises at once) use runBatch and runE1RMBatch.

Live calculator

The interactive calculator and showcase for this engine is the progoverloadcalc web app. The source for this package lives in the Sculpt AI monorepo.

License

MIT