Hillband: a pace band that knows your hills

Enter a goal time and get a printable wrist pace band. Add a GPX file of your course (pass) and the splits become slower on climbs and faster on descents while still adding up to your goal time. Everything is worked out in your browser, and your file is never uploaded.

How the hill adjustment works

Your GPX track is read in your browser, resampled every 20 metres (or a little wider on very long courses) and its elevation is smoothed over about 180 metres, because GPS elevation is noisy and raw numbers would invent hills. For each short stretch the grade is turned into an effort multiplier from the running energy-cost curve of Minetti and colleagues (Journal of Applied Physiology, 2002). We take the square root of that cost ratio, limit grades to 10% downhill and 15% uphill, and count only half of any downhill saving. Those damping choices are ours, so the result is an estimate and not a measurement. Then every stretch is scaled so the splits add up to your goal time exactly.

If your GPS track is a little longer or shorter than the official distance (within about 10%), choose the official distance and the course is scaled to fit it, and the band says so. If the two differ by more than that, Hillband asks you to pick the matching distance rather than stretch your hills. Isolated GPS jumps and single-point elevation spikes are removed before smoothing. Minetti measured treadmill running by trained mountain runners, so treat the result as a guide. If your file has no elevation, or its elevation is flat, Hillband says so rather than guessing. Your GPX file never leaves your browser; the page itself loads web fonts and a visitor counter, and the only other request is the pass key check. This is a pacing aid, not coaching or medical advice: heat, wind, fuelling and fitness change real races.