So... the world's best sprinters (so far as I know) max out their speeds at about 35 MPH.
A mile is 5280 feet.
That's 1760 yards.
A yard is a little less than a meter.
So roughly 61600 meters per hour. (35 MPH)
Comes out to roughly 17.1 meters per second.
A combat phase is three seconds.
53 meters/combat phase (at a running multiplier of 3) goes right back to 17.1.
Characters can't be made with that much quickness.
Admittedly, you can achieve those speeds through magic, shapeshifter running modifiers, etc.
Still... we're talking about top-of-the line, non-augmented, human runners NOW.
Even with the athletics kick increasing running range...
Sorry... I guess I'm complaining about the fact that Michael Johnson would be a Godlike gunbunny, I suppose.