Arm swinging reduces the metabolic cost of running

Jul 18, 2014 by Kathryn Knight
Arm swing reduces the metabolic cost of human running. Credit: Nicole E. Look.

Have you ever tried running without swinging your arms? It's not easy. Each step jars and it feels like hard work: but is it? Christopher Arellano, from Brown University, USA, says, 'We know from the literature that arm swinging plays an important role in balancing the motion of the swinging legs.' But it wasn't clear how the upper body movement affected the metabolic cost of running. And when Arellano and his thesis advisor, Rodger Kram, from the University of Colorado, Boulder, USA, looked into the literature to find out whether the metabolic effects of arm swinging had been measured, they found few studies and those that they did find did not agree. With the jury out, Arellano and Kram decided to embark on a thorough study of the impact of arm swinging on the metabolic cost of running.

Fortunately, when Arellano initiated the study he was based in Boulder, which is home to a community of dedicated : 'It is never a problem to recruit people', he laughs. Having calculated that he required 13 runners to generate sufficient data, Arellano selected eight men and five women who were all committed runners. Inviting each runner to the lab, Arellano asked them to run normally on a treadmill for 7 min as he measured their oxygen consumption rates and the amount of that they exhaled. Then he asked them to run without swinging their arms by holding the arms loosely behind the back, crossing the arms across the chest, and holding the hands on the top of the head. 'I think everyone conceded that the most challenging run was the one with the hands on the top of the head,' chuckles Arellano, who recalls the runners complaining about how tired their arms were at the end of the session.

Having measured the athletes' oxygen consumption rates and carbon dioxide production, Arellano then calculated the of each runner when they were swinging the arms and holding them in all three positions. Comparing the four metabolic rates for each individual, Arellano and Kram could see that swinging the arms reduced the runners' energy costs by 3% (relative to when they held their arms behind their backs). Arm swinging also saved an impressive 13% compared with when they held their hands on their heads. And when Arellano analysed the athletes' shoulder movements, he could clearly see that the runners had compensated for the loss of the counterbalancing swinging arms by increasing the amount that they swivelled the upper body. 'Whether they knew it or not, they all compensated in a very similar way by increasing the amplitude of their torso rotation', recalls Arellano.

Swinging the arms clearly saves energy for runners, and helps to minimise the amount that we rotate the body while swinging our legs, which led Arellano and Kram to wonder whether the metabolic benefits of arm swinging outweigh the cost of carrying the limbs. Explaining that they were interested in how metabolic energy is partitioned between different aspects of an activity, Arellano says, 'The arms weigh about 10% of the body, so if we took them away we could hypothetically save 10% of the metabolic cost of , but at the same time you wouldn't have any mass to counteract the swinging of the legs, so running would be more difficult to stabilise.' And Arellano is keen to follow up on two of the runners whose running costs were unimproved by moving their . 'Either they are not getting the benefit of arm swinging or somehow they modified their running style to keep the metabolic costs the same', he says.

Explore further: Mathematics to improve running

More information: Arellano, C. J. and Kram, R. (2014). "The metabolic cost of human running: is swinging the arms worth it?" J. Exp. Biol. 217, 2456-2461.

add to favorites email to friend print save as pdf

Related Stories

Mathematics to improve running

May 15, 2014

How can runners improve their performance, weight and fitness? Amandine Aftalion from the Mathematics Laboratory in Versailles (CNRS/University of Versailles-Saint-Quentin-en-Yvelines) and Frédéric Bonnans from the Center ...

Marathon runners' times develop in a U shape

May 28, 2014

Spanish researchers have demonstrated that the relationship between marathon running times and the age of the athlete is U-shaped. The work shows the unusual fact that it takes an 18-year-old athlete the same amount of time ...

Recommended for you

Scientists target mess from Christmas tree needles

17 hours ago

The presents are unwrapped. The children's shrieks of delight are just a memory. Now it's time for another Yuletide tradition: cleaning up the needles that are falling off your Christmas tree.

Top Japan lab dismisses ground-breaking stem cell study

Dec 26, 2014

Japan's top research institute on Friday hammered the final nail in the coffin of what was once billed as a ground-breaking stem cell study, dismissing it as flawed and saying the work could have been fabricated.

Research sheds light on what causes cells to divide

Dec 24, 2014

When a rapidly-growing cell divides into two smaller cells, what triggers the split? Is it the size the growing cell eventually reaches? Or is the real trigger the time period over which the cell keeps growing ...

Locking mechanism found for 'scissors' that cut DNA

Dec 24, 2014

Researchers at Johns Hopkins have discovered what keeps an enzyme from becoming overzealous in its clipping of DNA. Since controlled clipping is required for the production of specialized immune system proteins, ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (1) Jul 18, 2014
8 males, 5 females, and the study was based on metabolism while running? Have you read Born To Run?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.