Billat 30-30 Physiology: Using SmO2 and ThB to Identify True VO2max Stimulus

Comparison of SmO2 resaturation capacity in early vs. late Billat intervals showing the failure of muscle re-oxygenation.

Billat 30-30 Physiology: Why Garmin Stamina Contradicts the SmO2 Test By Coach Wharton April 29, 2026 Billat 30-30 Physiology is a foundational concept in high-intensity training, typically involving 30 seconds of maximal aerobic power followed by 30 seconds of active recovery. The goal is simple on paper—spend as much time as possible at VO2max intensity. […]