The Science

VidarFit is evidence-informed. Every system below lists the research behind it — mostly primary, peer-reviewed studies, plus a few credible secondary sources, labeled as such. Some magnitudes are practitioner-derived, and those carry a label too. Not every number is peer-reviewed; saying which is the point.

AppliedLive in the engine today.
CalibratingLive in the engine; some magnitudes flagged for recalibration.
BetaIn active development.

Recovery & freshness

Calibrating

Evidence Medium — The curve shape and per-muscle recovery windows are well studied; several dose magnitudes are practitioner estimates.

Tracks recovery muscle by muscle on a non-linear (exponential) curve, so each session trains what's fresh and spares what's still repairing — heavier, higher-RIR, and eccentric work all extend the window.

Honest note. The curve shape and per-muscle recovery windows come from this literature; a few secondary-mover credits and the running→set-equivalent doses are practitioner estimates, labeled low-confidence in the calibration notes. A separate low-confidence assumption sets how much of a run's dose lands immediately — its freshness-at-t=0 amplitude: no source calibrates that against our freshness scale, so it stays a monotonic heuristic pending your own recovery data.

Key sources11

Readiness & autoregulation

Applied

Evidence Low — The check-in instrument is validated; how much a low score should trim volume and load is mostly practitioner heuristic.

A 30-second daily check-in — sleep, energy, soreness, time — sets a readiness score that adjusts the day's volume, load and RIR out loud, rather than silently under- or over-reaching.

Honest note. The instrument itself — subjective wellness over objective monitoring, and the choice to autoregulate out loud — is directly evidence-based and validated. The deload dose-response on top of it (how much a lower score trims volume, load and RIR) is a practitioner heuristic, not a calibrated dose-response: our own backing review rates those magnitudes Medium down to Low, and the load-factor mapping is its single largest evidence gap. The per-user baselining that would keep a chronically harsh or lenient self-scorer honest — the report's main anti-gaming safeguard — is not yet built.

Key sources8

Strength-gain feasibility

Calibrating

Evidence Medium — Gain rates trace to real longitudinal datasets; the calibration wrapped around them is lower-confidence.

When you set a target lift and a date, it charts an honest trajectory from evidence-based weekly gain rates by training age and lift — easing off when you're ahead, adding work when you're behind, and refusing to promise a number that isn't reachable in the time.

Honest note. The expected rates of gain come from these datasets. The limits that keep a projection realistic, and the adjustments for lifts the datasets do not measure directly, are VidarFit calibration assembled from that evidence and flagged lower-confidence — considered judgements, not physiological thresholds.

Key sources10

Strength-to-weight ratio

Applied

Evidence Medium — Deterministic arithmetic on your own logs; the one primary source here mainly backs the caveat, not population comparisons.

For eligible barbell lifts, divides an estimated one-rep max (from a set of 10 reps or fewer) by your most recent logged bodyweight — shown alongside, never instead of, the underlying lift estimate.

Honest note. The ×BW value is deterministic arithmetic, not a body-composition or health score. Simple ratio scaling can still favor lighter athletes and does not make different exercises, sexes, ages, or techniques directly comparable — so no Beginner/Advanced/Elite population tier cutoffs are applied. Your own trend over time is the honest comparison.

Key sources1

Load & effort (RIR)

Calibrating

Evidence Medium — The %1RM–reps relationship is peer-reviewed; the base reps×RIR chart is practitioner-validated, not peer-reviewed.

Uses a rep-range and reps-left rule for eligible weighted muscle-building progression. Load estimates still help choose starting weights and serve other workout types; estimated one-rep max remains a separate progress measure.

Honest note. The max-reps-at-%1RM relationship and the 1RM-prediction equations are peer-reviewed. The base reps×RIR→%1RM lookup derives from the RTS/Tuchscherer coaching chart, which is practitioner-validated, not peer-reviewed — we disclose that openly and the primary literature calibrates its shape. The overhead-press (vertical-press) load table carries no OHP-specific reps-to-failure data: it is extrapolated as a flat offset from the bench table — a LOW-MED-confidence magnitude — and for high-stakes vertical-press prescriptions we fall back to the bench table. The displayed deadlift one-rep max also carries a small upward correction: a practitioner-applied, display-only adjustment (LOW confidence, never fed into your prescribed loads) tied to LeSuer's finding that the standard equations underestimate deadlift 1RM by roughly ten percent — so that one figure is not itself a peer-reviewed prediction.

Key sources5

Running

Beta

Evidence Medium — Intensity distribution and injury-aware progression are strongly evidenced; pace and heart-rate zones start from textbook and age-estimate priors.

Prescribes easy / threshold / interval paces and personalized heart-rate zones, and builds a run plan labeled by your goal race distance and date, using a mostly-easy intensity distribution and injury-aware progression limits.

Honest note. The intensity-distribution and injury-progression evidence is strong. The pace-zone boundaries follow Daniels' system (a textbook, cited directly) as coaching-consensus starting zones — per-athlete pace calibration is planned, not yet built. Heart-rate zones start from an age-estimated HRmax (Tanaka) as a low-confidence prior that sharpens as you log real runs; the zone seams sit at the LT1 ≈ 70% and LT2 ≈ 88% HRmax thresholds and scale by heart-rate reserve, following the endurance-training literature below, while talk-test / RPE stays the primary signal because heart rate lags and drifts. The goal race distance labels the plan today; distance-specific periodization is still to come.

Key sources12

Nutrition

Calibrating

Evidence Low — Mixed, graded at its weaker half: the protein anchor is well-evidenced, but the calorie and rate-of-change magnitudes rest on narrative recommendations rather than dose-finding trials.

Sets protein, calorie and macro targets from your bodyweight, goal and a safe rate of change — enough protein to build or protect muscle, an energy target sized to the trajectory, not a fixed guess.

Honest note. Protein plateaus and deficit protein needs are directly evidence-based. The rate-of-gain targets are a deliberately conservative baseline (about 0.25–0.5% bodyweight/week for novice/intermediate, slower for advanced — Iraki 2019; gaining faster mainly adds fat, Helms 2023 / Garthe 2013), labeled lower-confidence because they trace to narrative recommendations, not dose-finding trials; the compliance→expected-progress multiplier is a modeled layer on top. A goal weight and date, when set, nudge that pace within the same safe range — never past it — and the calorie number stays an initial estimate that recalibrates from your logged weigh-ins. When you're cutting and have a body-fat figure, protein is set from your estimated lean mass (a composition-adjusted target aimed at protecting muscle — depending on your body fat it can land above or below the bodyweight-based number); note the underlying protein range was studied in already-lean athletes (Helms 2014), and a tape/scale body-fat figure carries a few points of error (RFM/Navy ~3.5 points, Woolcott & Bergman 2018), so an entered or estimated value is treated the same — as an estimate.

Key sources10

The large majority of citations above — the ones with no label — are primary, peer-reviewed studies. A few are marked secondary: a credible textbook, position stand, or established training system that is not itself peer-reviewed, used deliberately and disclosed rather than hidden. Weak or anecdotal sources are excluded entirely. The full provenance grading lives in the repository's evidence audit. Links open PubMed, PMC, or the publisher via DOI.