I'd like to see the study text. It says they used an instrumented treadmill and measured ground reaction forces. I assume that means forces exerted by the ground on the shoe. That doesn't measure forces exerted on the body by the shoe. After all, I think the goal is to cushion the body, not cushion the ground.

But maybe there is an assumption that forces on the body correlate to forces on the ground? That doesn't seem intuitive to me, though.

they cushion the impact for my running so that report can suck it

Unless the center of mass of the shoe is accelerating (and it isn't) those forces are the same.

Agreed, that actually is somewhat intuitive. The ground should be cushioned about the same as the sole of the foot. But there's something missing. The author states that the maximalist shoes encourage runner to "slam down their foot." What is the runner feeling that encourages that? In order to encourage a dramatic shift in behavior there must be some proprioceptive sense of cushioning. The implication seems to be that it's a false sense of cushioning...enough to encourage "slamming" but not one that affects forces? There's something missing....

I can't even get the abstract from the link... did you find it elsewhere?

Runblogger saw the presentation:

http://runblogger.com/2015/06/do-maximalist-running-shoes-reduce-impact-forces.html

A bit OT but why did it take so long for a company to make the midsole thicker? People have been looking for increased cushion for a long time. Is there a reason for the typical running shoe midsole thickness?

I think it's just a weight issue. Thicken that midsole too much, and the shoe gets heavier, pretty quickly.

Remember as well that there is no proof that thicker midsoles or 'more padded shoes' reduce injury whatsoever, so given that evidence, you probably don't want a super built up shoe - just one that's thick enough to be comfortable even when running on roads and irregular surfaces.

I hear ya. All my feet and knee problems went away once I went to a maximalist shoe. I have also increased my weekly distance.

So that report can suck it.

Not so sure about that - since the whole point of cushioning is to act as a spring between the foot-shoe interface and shoe-ground interface, then the shoe-foot interface will not necessarily have equal forces at all times as shoe-ground interface acting on the treadmill. The summed force*time vector per step at both points will be approximately the same, but the instantaneous force at a given time does not necessarily have to match.

Imagine a shoe where you literally walk on huge springs or little trampolines - it's clear at that point that the ground-shoe interface and foot-shoe interface won't have equal forces. Running on a treadmill with such springy shoes would probably appear fairly violent to the treadmill (especially when the shoe banged into it on contact), but would probably be very easy on the runner.

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STAC Zero Trainer - Zero noise, zero tire contact, zero moving parts. Suffer in Silence starting fall 2016

Newton's first law tells you they have to be the same. If you're looking at the shoe, while it's in contact with the ground it's not moving, right? It's constrained by the ground, so it can't can't move. It's got forces applied to it from the ground and the foot.

F=m*a. It's not accelerating because it's stationary. So a =0. This leads us to conclude that F = 0. So unless there's another force-applier other than foot & ground, we must conclude that foot and ground apply equal & opposite forces.

And let me turn your spring-shoe scenario on its side. Say that normal-shoe running is like crashing into another person. Big forces, hurts a lot. Now have one person take a yoga ball hold it in front of them, and crash again. Your proposal is that the person holding the yoga ball will be cushioned, while their crash-partner will still feel a violent collision. Which I can tell you from experience isn't the case.

The shoe and foot are not moving literally in lockstep. The foot is going to move relative to the shoe during the contact with the ground, and so the forces between foot-shoe and shoe-ground will not be identical, even if the shoe's CoM is somehow nonmoving.

Also, the CoM of the shoe will likely move downwards very slightly as the internal cushion structures under the foot deform like they're designed to.

The impact in the trampoline-shoe is because the hard structure of the trampoline-shoe will hit the treadmill and nearly instantly stop (like the sole of a real shoe), while the foot will continue moving downwards and be caught by the trampoline/spring. Your yoga-ball example would apply if the yoga ball had some hard structure on one side. The guy on the soft side would have a pleasanter experience while the guy getting hit by the "sole" of the yoga ball would have a bad day as it collided with him and decelerated quickly.

Put more succintly, I guess I'm saying that the initial shoe-ground collision needs to be thought about when measuring from the treadmill. That initial collision is going to be more or less a fixed level of force no matter the padding of the shoe (assuming the shoe weight is the same). Once the shoe is stopped, you're probably right that the force at any given time between ground-shoe and shoe-foot will be quite similar.

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STAC Zero Trainer - Zero noise, zero tire contact, zero moving parts. Suffer in Silence starting fall 2016

This was a bit of my experience on Hoka Bondi. Keep in mind I have some nerve damage in my left leg. Extreme padded shoes made my bad knee worse. No padding/minimal padding on grass/treadmill or moderate padding on pavement seem to work best for me. In my case, maximal padding seems to encourage slamming. My knees hurt the least sprinting with vibrams on grass. They hurt running with padded shoes on grass.

This just in: Hollywood stuntman dies after reading this study and leaping from a 4th story window onto a yoga mat.

His last words were " I read on the internet that all cushioning is the same... "
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" I take my gear out of my car and put my bike together. Tourists and locals are watching from sidewalk cafes. Non-racers. The emptiness of of their lives shocks me. "
(opening lines from Tim Krabbe's The Rider , 1978

The shoe, particularly the midsole, is like a spring/mass/damper. (Really like a spring/damper, the mass is negligible compared to the person.)

All spring/mass/damper systems have a transfer function, including the shoe midsole. So what happens on one side of the system (the foot) will not be what happens on the other side (the ground). The midsole with both dissipate and return energy, and the magnitude and phase of the input will be transformed at the output (thus the transfer function).

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2015 USAT Long Course National Champion (M50-54)

I don't know about you but my foot does not move appreciably in the shoe, otherwise I get blisters.

Yes, this is true but we're talking about a shoe mass of say 600 grams moving a few millimeters. This effect is going to be at least 3 orders of magnitude smaller than the forces we're talking about in footstrikes. Probably within measurement error of the force plate on the treadmill. It's not worth mentioning really.


the force levels to stop the shoe itself are very low, again think of the weight of a shoe compared to the weight of a human. We're talking 2 orders of magnitude difference, so it's very small in comparison.

Your analogy relies on a homogeneous cushion (spring/damper), which a running shoe is not. To take the yoga ball analogy, now let's assume that there is a metal plate attached to one side of the ball. If one person holds the ball with the metal plate side facing outward and another person crashes into the plate they will not have similar experiences during the collision.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

As with all studies, need to look carefully at the authors and who funds it, etc.

Irene Davis, PhD is a colleague of Paul Lieberman, PhD from Harvard where they have been huge proponents of barefoot running. Dr. Lieberman's article in the journal Nature is often quoted by the barefoot/minimalist throngs. When your design a study to try to test your own other hypotheses ..

Also, I don't think this was published, but just a presentation at the American College of Sports Medicine recently (I've been to a few of these conferences).

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Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD

I switched to Altra Paradigms last fall. I used to fight injuries and lots of minor sniggles from running. Since then I have been running more with no injury and no discomfort. Works well for me.

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They didn't work for me either, I had really bad shin splints running with Hoka's, switched to Nike Pegasus and the shin splints went away.

ahem - the Pegasus is a padded shoe

I've had mixed success. On the one level I love how Hoka's "feel". On the other hand as a formerly very injury-free runner, I've had two significant injuries wearing Hokas. One of them was a severe ankle roll that put me out of action for 2 months. The 2nd was an awkward plant on a downhill flier that tweaked a knee ligament that put me out for another 2 months.. On both of those I was very suspicious that the "elevation" of shoe off the ground created the moment arm that caused the injuries, or at last made them worse. Also the shoes remove a lot of "ground feel" that can help prevent ankle rolls/awkward plants. I can't prove it, though, just my opinion from personal use.

Maximalist running shoe ? I think not...... I race with Zoot TTs and they also don't give me issues like the Hoka

29mm in heel 19mm in forefoot = cushioned
maybe it's the low stack height of the Hoka's that weren't for you