645 Stage 1 Episode 21 Week 4: Mobility & Stability ( Air Date 2021-07-19 ) Genre Reality category. Overview "Stage 1, Week 4. Breathing, stretching, and mobility drills intended to support recovery and performance. The program format is 45 minutes from activation warm-up through effort work and recovery cooldown. This is a Deload Week: the program keeps intensity up while reducing volume to support recovery before the next stage.".