How it worksThe scienceLog inJoin the waiting list
← Documentation

The Intensity Mix (easy vs quality)

The Intensity Mix shows how your training splits between easy and quality minutes over the last 4 weeks. Most weeks should land around 80% easy / 20% quality — easy running builds the aerobic base, and the quality minutes sharpen it. Too much quality is how you stall or get hurt.

"Quality" counts only the work-interval minutes of a hard session — a 60-minute threshold session of 2×15 min is 30 quality minutes, not 60. Its warm-up, jog recoveries and cool-down are easy, aerobic time.

The research this rests on

  1. Seiler & Kjerland (2006). Quantifying training intensity distribution in elite endurance athletes: is there evidence for an "optimal" distribution?. Scandinavian Journal of Medicine & Science in Sports 16(1), 49–56. ReadWhere the roughly 80/20 split comes from — what well-trained endurance athletes actually do.
  2. Stöggl & Sperlich (2014). Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Frontiers in Physiology 5, 33. ReadA controlled comparison of the distributions, rather than an observation of them.