Know Your Red Line

Stop guessing your training.
Anchor it to your physiology.

Know what easy actually is.

Know where threshold really lives.

Know your red line.

Train with certainty.

Takes 60 seconds. No credit card required.

Athlete metabolic testing Lactate threshold testing
VO2max testing Performance assessment

Built from 1,000+ VO₂max & lactate tests

Your Real Zones

Easy, Threshold, VO₂max — anchored to your current physiology, not age formulas

Your Week Built

See exactly what sessions to run and at what pace — purpose-driven, not guesswork

Adapts With You

Paces recalibrate as you train — your red line moves, your plan follows