TSS

TSS is a running data field that shows a live, continuously accumulating Training Stress Score for the activity in progress, instead of only a number after the workout ends. Made by Runima - https://runima.fit Each second the field estimates an intensity factor from pace or heart rate and folds it into the running total using the standard formula: TSS equals duration in hours, times intensity factor squared, times 100. Pace based intensity uses a grade adjusted, normalized graded pace, similar in spirit to Normalized Power for running: altitude and distance samples are smoothed with a rolling regression, and the Minetti running cost model converts the resulting grade into an equivalent flat ground pace. Heart rate based intensity uses percent heart rate reserve relative to lactate threshold heart rate, so resting heart rate differences between athletes are accounted for. Auto mode prefers pace and automatically falls back to heart rate whenever pace is not usable, for example indoors, on a treadmill, or with poor GPS reception. Pace only and heart rate only modes are also available. GPS on a wrist worn device is not a perfectly steady signal. TSS Field measures real elapsed time on every tick rather than assuming a fixed interval, treats an unusually long gap as a signal dropout rather than real data, resets its pace smoothing and falls back to heart rate for that tick, caps implausible speed readings, and caps how much any single tick can contribute to the total, so one bad reading cannot produce a large, incorrect jump in the score. The live TSS number and intensity factor are written to the FIT file every second, so after syncing to Garmin Connect the activity page shows a Training Stress Score chart and an Intensity Factor chart, plus a Total TSS summary stat. The field displays as a plain label and value, styled the same way as Garmin's own built in metrics. FEATURES Live, continuously accumulating Training Stress Score, styled like a built in Garmin metric. Automatic switching between pace based and heart rate based intensity, with manual pace only or heart rate only modes. Grade adjusted, normalized graded pace using a rolling altitude and distance regression and the Minetti running cost model. Heart rate based intensity using percent heart rate reserve relative to lactate threshold heart rate. Hardened against unstable GPS: real per tick elapsed time, automatic recovery from signal gaps, capped per tick contribution. Training Stress Score and Intensity Factor charts, plus a Total TSS summary stat, on Garmin Connect after syncing. Optional debug data logging to the FIT file for reviewing a specific run.

Improved TSS calculation.