ALPHAFLY AT TRIALS - letsrun please get a definitive statement from USATF

My concern regarding technology in shoes is related to this idea of extending the shoe modifications to large extremes and whether the final activity is one that ends up being what we know as 'running'.

Eg Let's be silly and say that they extend the stack height to be 5m and it becomes fastest to do some kind of weird shuffle...to do we still call that running?

Eg Let's be really silly...what if the stack height was ~42km and it took one step to complete a marathon. Would that be running?

I want running to be running. Even those shoes Lagat was wearing make me wonder if that is 'running'. There has to be a limit on stack height or things will eventually get beyond ridiculous.

Don't worry about it. Get your NEXT.

KraftMacAndCheese wrote:

HotLanta wrote:

Everyone will get the option to have a pair to race in. It's the athlete's personal choice if they want to accept a pair and race in them or not. Believe me or not, I don't give a śhit.

There, you said it will be their choice if they accept a pair. That implies they will be handed out, rather than having to be purchased. Those are the only two options. Either you get handed a pair, or you purchase a pair.

I don't think you're understanding...or perhaps I'm not explaining it well enough. Maybe you're hung up on semantics? Perhaps we're not discussing the same thing?

Read: if an athlete, (regardless of what brand they currently are under contract with), desires to race in the AlphaFly at the trials, they will have the opportunity to do so with a 24 hour Nike contract- this is THE ATHLETE'S PERSONAL CHOICE. With that structure, they will not have to be purchased. And yet, all 700+ qualifiers will not have a Nike gift basket with the AlphaFly handed to them with their bib upon arrival. This is what has been discussed on campus all last week. Obviously, it will all depend on what the IAAF decides on Friday. It would be a completely moot point if they are banned.

lorde wrote:

HotLanta wrote:

At no point in time did I ever say that "AlphaFlys will be handed out to everyone". I stated something of the notion that they will be available to any and all competitors that would like to utilize them. Stay tuned as to how this "rule" will be fulfilled.

Semantics aside, when will know more about this? I want to know if I should buy another pair of next%s for the race or wait on the alphas.

Hedge your bet: purchase the Next% and possibly have the opportunity for a free pair to race in, in Atlanta if you so desire. Either way is a win.

How's this for a statement.

DietBacon wrote:

Hardloper wrote:

There's a massive difference between 95% energy return and 85%. 95% energy return means you can maintain 3 times the kinetic energy (or 73% faster speed) than at 85%. Think of a bike or inline skates as something approaching 100% energy return. You still provide all the power but you can maintain a much higher velocity because you're not losing energy every footstrike.

I'm an engineer an trying my best to understand how you came up with these figures but seriously struggling. Are you suggesting that if shoes returned 10% more of the energy put into them the world record would be in the vicinity of 1h15m-1h20m?

Yes, the key is not energy returned but energy lost. A shoe that loses 5% of energy allows you to maintain 3 times the kinetic energy of one that loses 15% (kinetic energy varies with velocity squared). There will probably never be a shoe that returns 95% of energy per stride, but inline skates probably maintain at least that and people can rollerblade a ~1 hour marathon.

Hardloper wrote:

DietBacon wrote:

I'm an engineer an trying my best to understand how you came up with these figures but seriously struggling. Are you suggesting that if shoes returned 10% more of the energy put into them the world record would be in the vicinity of 1h15m-1h20m?

Yes, the key is not energy returned but energy lost. A shoe that loses 5% of energy allows you to maintain 3 times the kinetic energy of one that loses 15% (kinetic energy varies with velocity squared). There will probably never be a shoe that returns 95% of energy per stride, but inline skates probably maintain at least that and people can rollerblade a ~1 hour marathon.

That's nonsense. An inline skate doesn't return the energy in the same way at all - the skate is pushed forwards, hits the ground and then (in contrast to a shoe with no wheels on it) overcomes friction to allow the momentum of the skater to be maintained more or less in a horizontal direction.

A cushioned shoe allows the potential energy of a falling object (the runner) to be absorbed, stored and returned either back in the direction it came from, or (after some energy is used to rotate the shoe) in a new direction, a blend of forwards and upwards.

The stack height limit on its face seems reasonable, but now you have to define exactly what is included in such a measurement. Would it include the insole? Nothing would prevent Nike from redesigning the shoe so that the upper would go a third of the way down over the cushion, thereby making the shoe appear to have much less cushion.

With the Alfa Nike is showing off the cushion, but it could also finca way to incorporate more of it into the “upper”, arguing that is not part of stack height.

Just like with VF though, if people feel good in the shoe, they will buy it.

DC Wonk wrote:

The stack height limit on its face seems reasonable, but now you have to define exactly what is included in such a measurement. Would it include the insole? Nothing would prevent Nike from redesigning the shoe so that the upper would go a third of the way down over the cushion, thereby making the shoe appear to have much less cushion.

With the Alfa Nike is showing off the cushion, but it could also finca way to incorporate more of it into the “upper”, arguing that is not part of stack height.

Just like with VF though, if people feel good in the shoe, they will buy it.

How do you think they measure stack height? With a ruler up the side of the shoe?

A simple device could do it. Imagine a lowercase h but with one leg of the bottom of the h shorter than the other by the defined max stack height. Left hand side of the h sits rests on the floor, right hand side of the h must clear the inner of the shoe. Simple!

So I guess no alphaflys then.

You have to measure it from the outside of the outsole to the inside of the insole, so you'd use calipers. Very easy to do.

His Twitter post is just a cut and paste of the post that I made on Facebook.

It’s true. The Alphafly will be available to any athlete in Atlanta who has the trials qualifying standard.

What's the update? saw someone from Nike's tweet was deleted