The Yigri guidebook
Understand what your running is telling you.
Clear, source-backed answers and comparisons for the moments when pace, heart rate, weather, training, or equipment make a run harder to read.
Browse the collection
Guides for better comparisons
Start with the question that showed up in your last run.
answer · performance
Why heart rate is higher at the same running pace
How to interpret a higher heart rate at a familiar pace using weather, hydration, route, fatigue, and comparable runs.
Read guide
answer · training
What happens to fitness during a marathon taper
What taper research says about lower training volume, maintained intensity, and unfamiliar run data before race day.
Read guide
answer · weather
How heat affects running pace
Why the same effort can produce a slower pace in warm conditions, and how to compare hot-weather runs without mistaking weather strain for lost fitness.
Read guide
answer · shoes
How carbon-plated shoes change workout comparisons
Why pace and heart-rate trends can shift after a shoe change, and how to compare workouts without crediting every difference to fitness.
Read guide