Coach's Call Sweet Spot 2x6 Short The library's shortest sweet spot, authored 2026-08-13 to close a 20-minute hole: below 25 minutes the catalog held only recovery, VO2 and anaerobic work, so a rider with 20 minutes got an easy spin or top-end - nothing moderate. It reaches the comeback branches first (low_ctl_return could otherwise never close its own quality gate) but is a general entry, not a comeback-only one. Hickson 1981/1985 is the nearest evidence - cutting duration maintains VO2max provided INTENSITY survives - though that is MAINTENANCE evidence in previously-untrained subjects, so applying it to rebuilding is an extrapolation, LOW/CONSENSUS by this repo's convention. Sweet spot as a distinct zone has no primary RCT either. Dose is 900s in band, not the category's 1100s: at 20 minutes the full floor would leave 100 seconds for warmup and cooldown combined. bike