pretty fast I guess

In the distance ahead of him, he saw Accelerator slightly lowering his entire body like a
spring.
“Ah hah! See!? You’re slow, so slow, so very slow! Can you become a fox and bring some
enjoyment to your hunter or are you nothing but a pig to be eaten, you lowly thug!?”
At that time, there were about 30 meters between Accelerator and Kamijou.
Despite this, Accelerator brought that distance to zero in only two steps.
The gravel at his feet exploded as if from a rocket and Accelerator charged toward
Kamijou with tremendous speed as he moved almost like a rock skipping on the water.

- Toaru Majutsu no Index Volume 3, Chapter 4 Part 6