I am not sure, but evolution theory said we inherited traits of ape, that's why we swing our arms forward when we are walking. Steven Collins, a biomechanical engineer at Delft University of Technology discovered, that this is a more efficient way of walking. Not only we cannot balance, but we will use up 25% more energy to walk without swinging our arms. Off course this make sense, or else we would have urge to pick up a cup with our leg from time to time.
Mystery solved – by Ministry of Silly Walks
Good news for those slim down wanna-be. Try walking while keeping your hand still. Tell me the result if nobody laugh at you.