How Velocity-Based 1RM Estimator works
Methodology for the Velocity-Based 1RM Estimator: load-velocity profiles, MVTs, and confidence intervals.
Scope
Estimates one-rep max from a single sub-maximal lift's mean concentric velocity and weight, using published linear load-velocity profiles for squat, bench, deadlift, and overhead press.
Inversion of the load-velocity equation lets you predict %1RM (and from there 1RM) from one rep — useful for warm-up auto-regulation, peaking blocks, and avoiding true 1RM testing under high CNS cost.
Formula
%1RM = a − b × mean_concentric_velocity (m/s):
- Squat: %1RM = 109.5 − 64.6 × v (MVT ≈ 0.30 m/s)
- Bench press: %1RM = 115.3 − 75.8 × v (MVT ≈ 0.17 m/s)
- Deadlift: %1RM = 100.0 − 56.0 × v (MVT ≈ 0.18 m/s)
- Overhead press: %1RM = 100.0 − 70.0 × v (MVT ≈ 0.20 m/s)
Estimated 1RM = lifted_kg / (predicted_pct / 100). Confidence interval ± ~5–6% (sigma derived from validation studies).
Coefficients
| Lift | a (intercept) | b (slope) | MVT (m/s) |
|---|---|---|---|
| Squat | 109.5 | 64.6 | 0.30 |
| Bench | 115.3 | 75.8 | 0.17 |
| Deadlift | 100.0 | 56.0 | 0.18 |
| OHP | 100.0 | 70.0 | 0.20 |
Data sources
- González-Badillo JJ, Sánchez-Medina L. Movement velocity as a measure of loading intensity in resistance training. Int J Sports Med. 2010;31(5):347-352. — PMID 20180176. Established the bench press load-velocity profile.
- Sánchez-Medina L, Pallarés JG, Pérez CE, Morán-Navarro R, González-Badillo JJ. Estimation of relative load from bar velocity in the full back squat exercise. Sports Med Int Open. 2017;1(2):E80-E88. — Squat load-velocity profile and MVT.
- Mann J.B. Velocity-Based Training: Theory and Application for Sports and Performance Training. 2016. — Practical zones (max strength / strength-speed / speed-strength / starting strength).
Assumptions
- Bar velocity is mean concentric (not peak) measured by a validated device (Vitruve, GymAware, Tendo, etc.).
- The lift is performed with full intent — sandbagging the rep underestimates the load on velocity profile.
- Profile is generic across populations; individuals may sit ±5% from the published curves.
Approximation range
±5–6% on estimated 1RM at typical strength-training velocities. Accuracy collapses below the lift's MVT (grinding reps) and above the highest validated velocity (~1.0–1.2 m/s for unloaded warm-ups).
Limitations
- High-risk tool — do not use the predicted 1RM as a target weight without warming up to it across multiple builds.
- Profiles are population averages; competitive lifters often build their own personal profile in software.
- The model assumes free-weight bar mechanics; machine-based VBT readings deviate.
Reproducibility
Squat 100 kg @ 0.50 m/s: %1RM = 109.5 − 64.6×0.50 = 77.2%. Estimated 1RM = 100 / 0.772 = 129.5 kg. CI 95% ≈ 123–136 kg.
Change log
- 2026-05-08: methodology page first published.
Related tools
- One-Rep Max Calculator — Rep-based 1RM estimation alternative.
- RPE to Percentage Converter — Subjective-effort alternative.
Worked example
Computed by the same engine bundle served at
/engines/velocity-based-1rm.js. Re-runnable: the values below
are the literal output of compute(engineInput).
Input
- tool
- velocity_based_1rm
- bar_speed_m_per_s
- 0.5
- weight_kg
- 100
- lift_type
- squat
Output
- estimated1Rm
- 129.5
- predictedPctOf1Rm
- 77.2
- liftType
- squat
- weightKg
- 100
- barSpeedMPerS
- 0.5
- ci95Low
- 123.1
- ci95High
- 136
- velocityZones
- [{"label":"Max strength (90-100% 1RM)","velocityMin":0.15,"velocityMax":0.45,"intent":"absolute strength"},{"label":"Strength-speed (80-90% 1RM)","velocityMin":0.45,"velocityMax":0.65,"intent":"strength under speed"},{"label":"Speed-strength (60-80% 1RM)","velocityMin":0.65,"velocityMax":0.95,"intent":"explosive intent"},{"label":"Starting strength (<60% 1RM)","velocityMin":0.95,"velocityMax":1.5,"intent":"speed development"}]
- recommendedZone
- Strength-speed (80-90% 1RM)
FAQ
- What does the Velocity-Based 1RM Estimator calculate?
- Methodology for the Velocity-Based 1RM Estimator: load-velocity profiles, MVTs, and confidence intervals.
- What inputs does the Velocity-Based 1RM Estimator require?
- It takes the following inputs: bar speed m per s, weight kg, lift type.
- What does the Velocity-Based 1RM Estimator return?
- It returns: estimated1Rm, predictedPctOf1Rm, ci95Low, ci95High, recommendedZone, velocityZones.
- Is the Velocity-Based 1RM Estimator free to use?
- Yes. It runs entirely client-side in your browser with no signup, and is also importable as an ES module engine for AI agents.
- What category does the Velocity-Based 1RM Estimator belong to?
- Strength. See the methodology above for formulas, assumptions, and limitations.