About
Every project has an origin story. This one is short: a late night, an AI coding assistant, and no plan. The nonsense I expected to find the next morning turned out to be the skeleton of something worth keeping — the arithmetic behind planning a race, in a form I actually wanted to use. I finished it properly. What came out of that night is this: The Predictive Runner.
The whole set lives on the Tools & Calculators page. For now, each tool returns one number to carry into a race plan; none of them predicts a finishing time yet. There are still a few pieces to build before that’s possible — but that’s where this is heading: combining the critical-power model, fatigue exponent and environmental adjustment into a finishing-time predictor.
Credit where it is due
Several of these calculators are ports of one calculation each from the SuperPower Calculator, a running-power workbook built by Coach Steve Palladino et al. This site would be poorer without it, and any error in the port is mine, not theirs.
The site is also built on a good deal of open-source software, and on a typeface it serves itself. Those notices are on the Licenses page.
Where your data goes
Your running data goes nowhere. A .fit file you drop into a tool is read in your browser and charted there — never uploaded. Your athlete settings live in the browser’s local storage, deliberately not in a cookie: a cookie is sent to the site on every request, which would put your weight and gender in the server’s log. Local storage is never sent anywhere.
The server keeps an access log, as any web server does: which pages were requested and when, the referring page, and the browser. The last part of each IP address is dropped before the line is written, and that log is how visits are counted — the page loads nothing from another site to do it.