Ah damn how silly of me, I know that! 

Thanks for pointing it out!  Fixed! 

When a person moves, their arms move opposite to their legs, not with them (e.g. when the left leg is moving forward, then the left arm is moving backward). The movement of the arms is there to balance the body, and moving the way they do in your animation is very awkward. Try taking note of how your limbs naturally move when you walk.