What a block of readings looks like.
Inventing results would be the opposite of the point. What is real here is the shape: this is the structure the app records and the rule it applies. Below it, the literature the estimator is built on.
Load follows the reading
The jump is only taken when the measured effort said there was room. Week four of each wave backs off on purpose, and its week tick is ambered.
| Week | Top set | Prescribed | Measured | Call |
|---|---|---|---|---|
| W1 | 95 kg | 3 RIR | 3 RIR | On target |
| W2 | 97.5 kg | 2 RIR | 2.5 RIR | Room · add load |
| W3 | 101.5 kg | 1 RIR | 1 RIR | On target |
| W4 | 104 kg | 4 RIR | 4.5 RIR | Deload · hold |
| W5 | 104 kg | 3 RIR | 3 RIR | On target |
| W6 | 106.5 kg | 2 RIR | 2.5 RIR | Room · add load |
| W7 | 110 kg | 1 RIR | 1.5 RIR | Room · add load |
| W8 | 114 kg | 4 RIR | 4 RIR | Deload · hold |
| W9 | 114 kg | 3 RIR | 3 RIR | On target |
Where the guess goes wrong.
Self-reported effort against measured effort on the same sets. The mass sits off the diagonal, and on one side of it: people think they are closer to failure than they are. Rows are what the lifter said; columns are what the camera measured. Anything to the right of the diagonal had more left in it than the lifter believed.
This is the calibration the paid tier tracks over time: your reported number beside the estimated one, set after set, so the gap closes.
What the estimator stands on.
Velocity-loss-to-RIR bands are adapted conservatively from bar-velocity research. Those studies measured linear bar speed under known loads; RIRVana measures angular joint velocity from a phone camera, so the ranges are kept wide and the confidence honest.
Within-set velocity loss is an established index of neuromuscular fatigue[1], and concentric velocity falls as RPE rises, with strong inverse relationships across the powerlifts[2].
| Velocity loss | RIR | Range | Confidence | Basis |
|---|---|---|---|---|
| ≥ 45% | 0 | 0–1 | high | the last rep was a grind; at or near failure |
| ≥ 30% | 1 | 0–2 | high | pronounced slowdown, very close to failure |
| ≥ 20% | 2 | 1–3 | medium | clear fatigue, a couple of reps left |
| ≥ 10% | 4 | 3–5 | medium | moderate slowdown, several reps in reserve |
| ≥ 0% | 6 | 4–10 | low | far from failure; estimates this far out are rough |
- [1]Sánchez-Medina & González-Badillo (2011). Velocity loss as an indicator of neuromuscular fatigue during resistance training. Med Sci Sports Exerc.
- [2]Zourdos et al. (2016). Novel resistance training-specific RPE scale measuring repetitions in reserve. J Strength Cond Res.
- [3]Zourdos et al. (2021). Proximity to failure and total repetitions performed in a set influence accuracy of intraset RIR-based RPE. J Strength Cond Res 35(2S).
- [4]Steele et al. (2017). Ability to predict repetitions to momentary failure is not perfectly accurate, though improves with resistance training experience. PeerJ.
- [5]Remmert et al. (2023). Changes in intraset RIR prediction accuracy during six weeks of bench press training in trained men. Percept Mot Skills.
- [6]Renner, Mitter & Baca (2024). Concurrent validity of novel smartphone-based apps monitoring barbell velocity in powerlifting exercises. PLOS One.
- [7]Stronger by Science (2024). How to perfect your ability to predict repetitions in reserve.