Scientists: Don't let your coach change your arm swing - "Most people will settle into the swing that is the most efficient

MIC ITW wrote:

I believe economy and VO2max typically have an inverse relationship. They need to be looked at together.

An inverse relationship? Improved economy us a path to improved VO2max.

Rodger Kram wrote:

There is no objective evidence that changes to a person's customary running form improve their running economy.

Actually our study is strong support for the idea that changing from horrible form to normal form improves economy.

First, thanks for posting.

The objective evidence issue is a tricky one when it comes to endurance training, because there really isn't that much scientifically objective evidence to support a lot of what are commonly regarded as best practices for endurance training. Broadly speaking, the sport itself is the laboratory, and through imitation, trial, and error, many of the world's best runners train in remarkably similar ways, even if they don't have the peer reviewed studies to tell them that they're doing it right.

With sprinting, for instance, it's considered common sense that certain form tweaks lead to better performances. Coaches don't need studies to prove it, because they have the collective experience of all sprinting coaches. The same is true in many sports (I believe a previous poster referenced gymnastics and shotput). Sometimes you don't need a study to prove something works.

Distance running is different, though, in that the collective experience of all coaches in the field hasn't led to anything like a consensus about the relevance of working on "form." Under those circumstances, the additional fact that no scientific studies have been able to prove the efficacy of form manipulation seems like a FURTHER reason to discount it.

I think form manipulation is something of a superstition. Runners have an odd relationship with their bodies. On the one hand, they're very in touch with it, but on the other, they're never 100% sure how the body will react to the absurd demands we place on it in races. Doing form drills, core work, massage, and taking supplements are like the modern distance runner's rain dance. They're just hoping that something, anything might make a difference. But if any of these things did make a real difference, then I think those practices would have proliferated universally throughout the distance running world by now.

Great post. I agree with almost everything you said, except one thing in your last paragraph. It seems to me that drills and massage HAVE proliferated universally throughout the distance running world, at least among "elite" and collegiate runners.

Rodger Kram wrote:

With regard to competitive runners, I think that it would be interesting to repeat our study at 6:00 pace in some high caliber runners.

But, there is no evidence that at faster speeds arm swing comprises a larger or smaller % of the total energy required.

If you think that arm swing does comprise a greater %, what do you think comprises a smaller fraction at faster speeds?

Thanks for the responses in this thread.

As I'm sure you know, one thing that's been consistently observed with changes in running form, whether it's stride frequency or footstrike style or whatever, is that the runners studied are inevitably less efficient after changing away from their natural form. Do you think that some of this drop in efficiency can be overcome by adaptation? e.g. Mary Cain changes her form and becomes X% less efficient immediately afterward. She continues to run with this less efficient form for weeks/months. Does she eventually adapt to some or all of the change?

I'm particularly interested in how this relates to the gradual refinement in running economy that happens in experienced runners. You cited a study which showed that improvements in (presumably recreational runner) fitness over a 6-week program is attributable to physiological adaptations only, but studies of very experienced, well-trained runners find that performance improves in the later years of an athlete's career without concomitant increases in VO2 max despite race performance improving (example:

)—this means the improved performance can only be attributed to increased running economy.

[quote]Cornell Sucks wrote:

Arellano and Kram (2014) compared running with a subject-specific normal arm swing and running with the arms constricted. The authors hypothesized that running with the arms constricted would increase metabolic cost, thus indicating that arm swing may be beneficial. Arellano and Kram (2014) found evidence that supported this hypothesis as well as that arm swing decreased torso rotation. If you actually read the article that Arellano and Kram wrote, you would understand that they were not making a statement about whether or not biomechanists should change the way people swing their arms during running. [quote]sp2 wrote:

[quote]poor logic wrote:

The conclusion in this study is not what the title of this thread indicates.

grox wrote:

Rodger Kram wrote:

(...) then how much could possibly be gained by small changes ("improvements") to a runner's natural arm swing motion? Probably not much. That's all we are saying with regard to running form.

Measuring precisely the cost is interesting, but I am not sure that makes it easy to guess what `small' changes are going to make. I would never have imagined so big changes between these three positions, for instance.

And for some athletes, half a percent of just about anything matters a lot.

Exactly, energy costs aren't everything. In the last 120 metres of Cain's win in Eugene, her aggressive use of her arms cost her more energy. It also propelled her to speed up and win the race. It is not the runner who uses the least energy who wins the race, it is the fastest runner and especially the fastest finisher.

It must be Nenow

marathon man 21 wrote:

grox wrote:

Measuring precisely the cost is interesting, but I am not sure that makes it easy to guess what `small' changes are going to make. I would never have imagined so big changes between these three positions, for instance.

And for some athletes, half a percent of just about anything matters a lot.

Exactly, energy costs aren't everything. In the last 120 metres of Cain's win in Eugene, her aggressive use of her arms cost her more energy. It also propelled her to speed up and win the race. It is not the runner who uses the least energy who wins the race, it is the fastest runner and especially the fastest finisher.

Yet if she had been less energy efficient in the earlier part of the race, she might not have had the energy required to kick at the end.

Coach K wrote:

MIC ITW wrote:

I believe economy and VO2max typically have an inverse relationship. They need to be looked at together.

An inverse relationship? Improved economy us a path to improved VO2max.

It's not typical for the rich to get richer in nature. I'm quite confident you are wrong on this one, Coach K.

You are basically saying that in humans/animals a Prius is a path to being a Porsche.