Checkpoint - S5-E12
Continuity mistake: In the series 5 episode 'Checkpoint' when Buffy has just accidently axed the dummy, watch her blindfold. It goes from being pushed up above her forehead on her hair, to being right down by her eyes. This changes between every shot. (00:27:55)
Answer: She has superpowers, ergo fast movement. The reason she outruns him so easily in "Touched" is that she stops trying to actually fight him and just dodges instead.
Shay