What Outrunr runs on
A training plan is only as honest as the arithmetic underneath it. This page says what that arithmetic is, where it comes from, and who is behind the app — so you can check every number against its source.
What it is
Outrunr is a running app for iPhone and Android. You give it a goal — a first 5K, a faster 10K, a half, a marathon or an ultra — and a recent time you have actually run. It builds the whole block from that: base, build, peak and taper, every session with a target pace and a reason. The coach speaks the session into your ear as you run it. After every run, the plan re-prices itself and a confidence score says, without flattery, whether the goal is still on.
It is built in Australia by a small team led by a runner, not a coach. That is deliberate, and it shapes everything below: the app does not offer anyone's opinion about how you should train. It applies published methods, cites them, and shows its working.
The methods, and where they come from
Training paces and race equivalents: VDOT
The aerobic index behind every pace in the app is the Daniels & Gilbert model (Jack Daniels and Jimmy Gilbert, Oxygen Power, 1979; the modern form in Daniels' Running Formula). A race is converted into the oxygen cost of that velocity, divided by the fraction of maximum a runner can sustain for that duration. The same equation solved backwards gives the equivalent time at another distance and the easy, threshold and interval paces for that fitness. The parkrun time calculator is this model, in your browser.
Race projection: Riegel
Peter Riegel's 1981 formula, T2 = T1 × (D2/D1)1.06, is the second opinion on every projection. The app shows both and, where they disagree, says so — because the gap between them is a fair measure of how much the answer depends on endurance a short race cannot see. A raced personal best at the goal distance inside six months is trusted over either projection.
Age grading: WMA standards and the Fair tables
Where you sit among runners is read against the World Masters Athletics open standards, with age factors from Ray Fair's 5 km tables (Yale), placed on a percentile curve derived from several hundred thousand filtered race results. The app says which part of that curve is extrapolated rather than measured.
Pace zones
Five zones anchored to your race pace rather than to a heart-rate formula, with the easy zone's gap widening as runners get faster — the ratio of easy to race pace is not a constant, and the app does not treat it as one. Heart-rate zones, when you wear a monitor, use the Karvonen, Friel or Tanaka methods and are learned from your own hard runs rather than typed in from a chart.
Training load
Each run scores as duration times intensity; the acute-to-chronic ratio compares the last week to the last month. It is a widely used reading, and a contested one, so the app presents it as a caution rather than a verdict, and withholds it entirely until there is a month of history to compare against.
Shoe life
No manufacturer publishes a per-model lifespan, so the app prices a shoe by its midsole foam chemistry — EVA, TPU, PEBA and their blends — and by what the shoe has actually been through: distance, the runner's weight and the surface under it. The shoe replacement calculator is the same policy.
Numbers you can check
Every calculator on this site runs the same code the app runs, ported line for line and pinned to the app's own test fixtures. If the app and the website ever disagreed, the build would fail. The guides and race pages quote a number only when that code produced it. We have had to correct a sentence against our own maths before; the rule exists because of it.
What the app will not do
- It will not give medical advice, diagnose an injury, or tell you what to eat. It is a training tool. Check with a doctor before starting a program, and stop if something hurts.
- It will not pretend a goal is on when the numbers say otherwise. The confidence score goes down as readily as it goes up.
- It will not sell what you run. Your runs are yours; the privacy policy says what is collected, why, and how to delete all of it.
Who builds it
Outrunr is made by DTI Ventures Pty Ltd, an Australian company, and the person who started it still runs most mornings. Questions, corrections and sources we have missed go to admin@outrunr.com.au; a correction to a published number gets a reply and a fix.
parkrun® is a registered trade mark of parkrun Limited. Outrunr is not affiliated with or endorsed by parkrun. VDOT is a trade mark of its owner. Outrunr implements the published Daniels & Gilbert formula and is not affiliated with them.