Swing your arms while walking, or else!

I have a friend who does not swing her arms while walking.

Ever since I first saw her walk with her arms hanging straight down, I had suspected that it was not very efficient.

Recent research confirmed this suspicion.

According to the article “Dynamic arm swinging in human walking” in Proceedings of The Royal Society (B | Biological Sciences),

1. A “passive dynamic walking model with free-swinging arms” will swing its arms in the way that humans (should) do with no torques driving the arms.
2. “Experimental measurements of humans (n = 10) showed that normal arm swinging required minimal shoulder torque, while volitionally holding the arms still required 12 per cent more metabolic energy.”
3. “Walking with opposite-to-normal arm phasing required minimal shoulder effort but magnified the ground reaction moment, causing metabolic rate to increase by 26 per cent.”

Put in plainer English:

1. If you walk and do not think about your arms, they will naturally swing such that the right arm goes forward when the left leg goes forward and such that the left arm goes forward when the right leg goes forward.
2. If you hold your arms straight down while walking, you will burn 12% more energy.
3. If you swing your left arm forward when your left leg goes forward and you swing your right arm forward when your right leg goes forward, you will burn 26% more energy.

So swing your arms opposite your legs while walking, or you will waste energy — not to mention the fact that you might hurt yourself!

Have you ever had the same suspicion that I had after noticing someone not moving his or her arms while walking? Please leave a comment here. Thanks!