How do runners conserve ultraboost momentum after checkpointing, like in this video at 0:16

at least before 16d, the way to do this was to checkpoint before the explosion hit you, so that the speed was applied to you after checkpointing (i think).

now its apparently much harder than before, but i have yet to try it​, so i cannot confirm this.

cap your frames to 120 fps, do the nuke and pause, when paused and you hear the explosion, then checkpoint