Detecting Players not moving

So, I don't know if this IS a problem, but, just in case.

/testfor @a

{Motion:[0.0,0.0,0.0]}

This command should testfor anyone who's not moving.
But, no matter how I sneak,walk,sprint,jump,fall,fly,
the comparator is still on(it means that I'm still Motion:[0.0,0.0,0.0])

But, whenever I jump while sprinting(stat.flyOneCm is the move I think.)
I don't know if that's unusual, but I can't accept walk=not moving ,