Setting walk/run forwards/backwards animations from an objects speed

I've been searching all over google and whatnot for a day now, on how to accurately set animations from an objects speed. All I can find is "animate via controllers" but this is not what I need, as my game is multiplayer and locally the other players in my game do not have controllers, naturally. So how can I apply walking forward/backward animations to other players based on their movement?

 

I don't really understand what you mean that other players don't have controllers but maybe you should look at these videos
http://unity3d.com/learn/tutorials/modules/beginner/animation
9. Animator Scripting
and look for
anim.SetFloat("Speed", move);
...
or if it is because of multiplayer, maybe RPC-s