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OddSlug wrote:

What is the definition of this energy and how do we define how much is returned?

Before we get to that, the issue is how we define how the shoes should and can be reliably tested. That in itself is debatable (shoes seperate, shoes on, what kind of running, etc). Whilst several people here are saying how clear cut things are, even the actual authors who have published journal papers in this area openly concede that we don't understand exactly how they work and that more testing is needed. It is incredibly complex.

With prosthetic limbs used in running, it's easier to test because they are relatively simple parts. You can literally drop them from a given height and see how much they spring back up. That gives you a basic concept of static mechanical energy return (a huge oversimplification but hopefully you'll see what I mean). There are more dynamic tests that can be undertaken too. As others have said here though, no system that is passive in nature, is ever going to return 100%. You lose energy in the form of heat, sound, etc, etc.
UK Gearmuncher wrote:
OddSlug wrote:

What is the definition of this energy and how do we define how much is returned?

Before we get to that, the issue is how we define how the shoes should and can be reliably tested. That in itself is debatable (shoes seperate, shoes on, what kind of running, etc). Whilst several people here are saying how clear cut things are, even the actual authors who have published journal papers in this area openly concede that we don't understand exactly how they work and that more testing is needed. It is incredibly complex.

With prosthetic limbs used in running, it's easier to test because they are relatively simple parts. You can literally drop them from a given height and see how much they spring back up. That gives you a basic concept of static mechanical energy return (a huge oversimplification but hopefully you'll see what I mean). There are more dynamic tests that can be undertaken too. As others have said here though, no system that is passive in nature, is ever going to return 100%. You lose energy in the form of heat, sound, etc, etc.

As I said I will make an effort to read the links you shared in the discussion with Dev when I've got more time. I'd missed it but he is better articulating what I'm struggling with.

Apologies if I'm being dense but I don't see how testing can come before definition. In practical terms I completely understand how you should only regulate what you can test. So I see it from a sports body point of view. What can you test, define the regulation in those terms, go it.

But from a pure philosophical point of view surely there should be some description of this energy and return. What I'm doing is trying to counter the 'until a shoe returns 100% energy it's fine' argument. What does that statement even mean? Previously you said 'It is one benchmark but not the only benchmark..'. Are we saying it's a possible area for a benchmark once it's defined? My point is since we agree 100% isn't possible then it's meaning less.
OddSlug wrote:

1) As I said I will make an effort to read the links you shared in the discussion with Dev when I've got more time.

2) Apologies if I'm being dense but I don't see how testing can come before definition. In practical terms I completely understand how you should only regulate what you can test. So I see it from a sports body point of view.

3) But from a pure philosophical point of view surely there should be some description of this energy and return.

4) What I'm doing is trying to counter the 'until a shoe returns 100% energy it's fine' argument. What does that statement even mean?

5) Previously you said 'It is one benchmark but not the only benchmark..'. Are we saying it's a possible area for a benchmark once it's defined? My point is since we agree 100% isn't possible then it's meaning less.

Ok, lets take this back a step or two and I'll see if I can clarify a few things to help:

1) I'd recommend glancing through my review paper I put the link up for as this summarises the philosophical and ethical issues that are typically discussed with respect to such technology.

2) It can't. I think this is where we're getting confused. However, before we get to that, my attitude is that you have to discuss what running even is. That sounds a little odd but what that means is you have to philosophically define the sport itself first. For example, you need to discuss the role of technology in a sport first. For example, cycling tried to minimise and standardise bicycle technology's impact in the hour record for some years. In this case, are trainers part of running or should their impact be minimise ? If the answer is yes, it's open season on their design (to a point). If the answer is no, you then determine its key performance indicators (i.e. what makes running fast with relation to the footwear specifically) and then after that, you define and validate the best tests that provide those answers. As you infer, the tests need to be achievable and specific to the sport. To date, the full battery of required tests have not been conducted on these shoes - hell, we don't even know what these are yet as everyone concedes they don't know exactly how the shoes even work.

3) Yes, you're right. This goes back to my earlier point about defining first what trainers contribute and then defining tests to do that. Mechanical energy return is only one of those tests and not the only test you should run. However, the use of running shoes are so complex, no study yet has attempted to conduct the full range probably needed.

4) The 100% argument was taken from the IPC's sports rules that suggest any form of sports technology (such as prostheses) should be 'passive in nature' only. If you get more than 100% back it's likely not passive and is illegal. This is easy to investigate with prosthetic limbs but problematic with the human leg as the ankle actually generates power so it requires testing in a slightly different way. So far, the published studies typically do this in two ways 1) with steady state running on a treadmill and 2) mechanically loading the shoes (when not being worn). The often quoted line that the shoes are 4% better than anything else is based upon that they use 4% less physiological energetic cost to use when running in them or that they require less oxygen uptake to use when running at the same speed.

5) What I mean by that is that we simply need to investigate these tests using more than one method. I've mentioned two tests above as examples. The 100% comment is meaningful though as the shoes should be tested for their level of mechanical energy return - even if 100% or greater isn't hypothetically possible.

A key point to this is that the ethics should be discussed BEFORE any tests are designed. Any decision should be based on a joint assessment between ethical discussion and then physical tests. A problem is that few researchers are able to handle both extremes - hence why World Athletics had convened a working group made up of a range of individuals.
Last edited by: UK Gearmuncher: Jan 30, 20 8:33

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