Variable STEP_BACK_ANIMATIONConst

BACKWARD STEP Animation (후진보법)

Tactical backward step for defensive retreat while maintaining guard.

Animation phases:

1. Preparation (0-0.1s): Weight shifts to front foot
2. Movement (0.1-0.2s): Back foot lifts and extends backward
3. Landing (0.2-0.25s): Back foot plants, weight transfers
4. Stabilization (0.25-0.3s): Front foot follows, guard maintained

Distance: 30cm backward Duration: 300ms Guard: Maintained throughout