User blog comment:ImperiexSeed/Who else is annoyed with Caitlin's conclusion in 2x17 "Flash Back"/@comment-27673963-20160722014319/@comment-3423279-20160722030326

The whole "legs moving" thing is whats throwing you off, their legs moving are the same despite the incredible difference in speed the three have, Eobard uses the Tachyon Enhancement to force himself to absorb more Speed Force energy and move faster.

Zoom used the Velocity Serums which did the same as above but holding far more negative effects.

The fact that they are moving their legs at the same speed doesn't matter, it is the Speed Force Energy that matters.