top of page

Why Arms are Straight While Walking But Bent While Running? Ancestral Behaviour or Scientific Reason

Why Arms are Straight While Walking But Bent While Running? Ancestral Behaviour or Scientific Reason

Did you ever notice the position of your arms while you are walking or running? Besides, when you are exercising, it’s always recommended to bend your forearms and do squats. But why? Is there a scientific reason behind our movements, or is it something we inherited long ago from our ancestors?

There has been no research done yet to explain why. Wandering around the Harvard campus in 2015, Andrew Yegian saw a fellow student running with straight arms. And he suddenly realizes that we usually walk with arms straight, but why don't we run with consecutive arms and vice-versa.

Yegian, with his other colleagues, decided to experiment. They chose eight distinct students, to walk and run on a treadmill with arms both straight and bent. Selected students were ranging from daily runners to marathon competitors.

Six of those students wore an oxygen mask to record the usage of oxygen. He found out that they used 11% more energy while bending their arms than keeping them straight. Twisting the arms increased the amount of oxygen used, disclosing the clear advantage for straight-armed walking.

Yegian and his team thought running with arms bent would be more efficient, but when the results came out, there was no difference in the energetics.

Finishing Note

We did find out that walking with straight arms maintains our energy levels and keeps our oxygen usage as standard. Researchers say they still don’t know why we run with our arms bent, but Yegian thinks there is some benefit.

The experiment was conducted at lower speeds, so it could be possible that bent arms are apparent for a higher rate. Maybe bending the arms requires more energy from the shoulders to the elbow. Or it could be to maintain our balance while we swing our arms in time with our legs.

More research will be followed in the future, said Yegian. Until then, we know that energy is why we keep our arms straight when we’re walking, and there's probably a reason why we run with our arms bent. We’ll find out soon.

Around 2 billion years ago, our ancestors became accomplished long-distance runners and evolved running with curved arms. So, it could be possible that it already exists in our genes to run with bent arms.

You can run or walk; however, you like. Just keep running and live a healthy life.

SIGN UP to get such articles directly into your inbox.


Be the First to Expand Your
Intellectual Horizon!

bottom of page