A couple of months ago, the Journal of Experimental Biology published a study that looked at the energy cost of running with various different arm actions.
(The metabolic cost of human running: is swinging the arms worth it?).

The study’s conclusion was hardly earth-shaking. The authors found that running with a typical arm swing uses less energy and results in less torso rotation than running with hands on head, arms crossed over the chest, or arms behind one’s back. Runner’s World published a nice write-up (Arm Swing and Running Economy), but perhaps because the experimental results were non-controversial, the study didn’t generate a whole lot of discussion. I expect many readers felt it was a little silly to conduct extensive experiments to determine that running with your hands on your head is inefficient.

But here’s the thing: unless we’re sprinters, most of us aren’t really sure what to do with our arms.

I exempted sprinters because almost all of the good ones seem to practice the same technique, with a huge range of motion out of the blocks, leading to a powerful downward driving action once they reach full speed. Sprinters practice their arm actions all the time, refining their ability to coordinate arms and legs to first accelerate, and then maintain velocity over a shockingly short amount of time. Those who don’t get it right, don’t prevail.

No such consensus exists among distance runners, or rather, no matter what we might think about perfect form for swinging the arms, there are too many exceptions that challenge our preconceptions.

For example, the best 800m runner in the world in 2014 was Nijel Amos. In contrast to most 800m runners, when Amos sprints, his arms seem to swim through the air and are noticeably less compact. What can we make of this? Would Amos run even faster if he cleaned up his arm action to be more aesthetically pleasing?

I’ve been thinking about this because as a high school coach, I see every possible way of running and that includes unconventional, seemingly inefficient arm actions. How much effort should I put into correcting poor arm mechanics, and do I really know how to do that?

I seem to remember that one of Alberto Salazar’s first observations about the young Mary Cain was that she flapped one arm slightly, and that if she fixed that, she’d go even faster. I can only imagine the hundreds of hours of work that the two of them have done since then to address this perceived flaw. But has it really made a difference? How would we even know?

The great Murray Halberg, gold medalist at 5000m in the 1960 Rome Olympics, ran with a withered, nearly paralyzed left arm, the result of a Rugby injury in his childhood that damaged nerves, veins, and arteries in his left shoulder. Here’s what he wrote about it in his great autobiography “A Clean Pair of Heels”:

“A lot has been said and written about my injured left arm… at the risk of spoiling a few long-standing beliefs, I think it has been a help to me in running. Before the accident, I used to run slightly off-balance. After it, I adjusted to running with the arm tucked up, pumping myself along with my right. And my balance seemed better. I think it helps me greatly when I am running on tight-cornered board tracks. It supports the theory that there is some good in everything if you care to look for it.”

So I think that when it comes to what’s obvious about using arms when running, we need to practice a little humility. If someone chooses to study the metabolic cost of running with hands in their pockets, I think we should pay close attention to what they find out.

In the mean time, I’ll coach my runners to at least think about their arm actions, and especially with the new ones, to seek out a more efficient, more balanced arm carriage — even if I don’t know precisely what that will look like for each kid. Mostly I want them to run more, with the idea that running more will inevitably teach them more than any lessons I can give them. Right now, the fastest girl on my team runs with her arms quite open and almost by her side. It doesn’t look like classic running form, but when we tried to have her change it, she complained that it didn’t feel right.

Maybe her arms are too short to worry about adjusting her form to create a classic right-angle arm swing, or maybe life is.