WHY WE SWING OUR ARMS WHEN WE WALK

"During the noontime break, a friend of mine asked me why we swing our hands when we walk. I , too questioned myself , why? my mind keeps asking me so I look for anwers on the net and here's what I got."

Arm-swinging improves biomechanical efficiency, says Michael McPartland, Ph.D., of Harvard's BioMotion Laboratory. Notice during a walk or run that your limbs are "out of phase," left leg forward and right arm backward, etc. This way, body torque from the leg and arm swings counter each other, stabilizing the torso and head.

To prove this, try a brisk walk or slow jog with arms tightly crossed against your chest. Now both your hips and shoulders will rotate by an undesirable amount, wasting energy. Or try jogging and moving your arms "in phase," right arm and left arm forward together, etc. "This is very difficult and unnatural. And the faster you jog, the goofier it gets!"

Source: Answerbag.com