I have never seen Mirrors Edge but just to let you know; the legs are actually a part of another entity character. This character is placed at the same location as what is called the player "bobble" which is an invisible box that allows for collision tests. So, all the legs do is walk, run, and move side to side as well as backward in sync with how the player is walking. There is nothing that can be done with them, especially sliding into 2nd base or have a type of landing style.
The legs are just a sort of poor man's version of special effects without re-coding a major part of the source code.
Addendum:
I'm sorry, it's called "playerborble" instead of bobble.