The signature circuit and the axis the club is built on. A fixed passage from far heat to far cold and back, three times, each threshold marked and held. You do not choose the temperatures. You cross them.
What it does
Full contrast circuit, hot to cold and back
Fixed protocol, no decisions
Logged as a reading, not a class
Guided pacing at every threshold
The reading
Temperature
82°C ⇄ 4°C
Duration
45 min
Protocol
3 crossings, 45 min. 82°C heat, 4 min hold — 4°C plunge, 60 sec — 90 sec rest at the line. Repeat.