Not in my view, no. This whole issue is a question of efficiency, not enhancement as the level of energy return is not greater than 100%.

They have a new one coming out.....

https://www.nike.com/...-running-shoe-dr3mtS

Stack height sweep stake - I'm going in at 40mm at the heel.

It doesn't ban any currently sold shoe but stops the Alphafly before the Olympics and before that is on sale to the public.

I think the Daily Mail may not be clear about the distinction between the Alphafly and the Vaporflys and the intention could be to draw the line where we are rather than ban shoes that lots of people already have.

They also changed javelin weight to start with a fresh set of world/national records to get a restart after the 80s doping scandals

A

That has been taken down already !!

This is your area of expertise but how interesting is the 100% efficiency argument? How fast would someone run if they were 100% efficient? How efficient are we now? Efficient in terms of oxygen or calories? Can you put some flesh on the is 100% thing?

Consider this - the prosthetic limbs that were used by the likes of Oscar Pistorius and tailored to his bodyweight were around 90-95% efficient..... and these were springs and utilising a harmonic energy return effect to devastating effect. From what limiting data is out there on these shoes (and it is extremely limited), the energy return is circa 60% I believe. However, the number of studies are so few (<5) and the methods used open to debate that this figure isn't reliable yet. I should also add that this issue is as much philosophical as it is physical. Whilst I believe the shoes should be legalised from a scientific point of view, there are valid ethical reasons why these shoes may have to be banned.

However, I wouldn't put too much stock in the newspaper reports. It looks to be a case of where one person has had a tip or an opinion and the others followed it. I've seen just as many say they'll be kept as legal but that rules may well be coming. Wait and see is my feeling on this one............

Thanks for the perspective, it does help the discussion. So what I don't understand about your position is that 90-95% is devastating but a shoe would have to be over 100% before it was seen as an enhancement?

Just to clarify when you say "I believe the shoes should be legalised from a scientific point of view" do you mean remain legal (because they aren't currently illegal) or that because the current rule is subjective it needs to be specifically legalised?

It is still there...you do have to be a ‘member’ though.

As much as I dislike the 4% shoes, mostly because of price, secondly because I am not happy with Nike in general, I STILL would not support the shoes being banned. I think it is good for a company to release an innovating, and performance leading product. It brings competition, and further innovation to that industry. Eventually the playing field will level, and most shoe companies will have their "4%" shoe. In the meantime, I will continue to run in my Carbon X's.

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- Jordan

My Strava

Good questions.

1) 95% was devastating in relative terms within its own sport because the variety of prosthetic limbs used by athletes was diverse. They varied from those limbs (made by Ossur) down to fibreglass bodged solutions from their local health authorities that barely held together. The disparity between athletes was quite obvious and athletes were struggling to compete purely due to the equipment they could source. It's not quite so bad with trainers. The other issue about the prosthetics is that their benefits were dependant on whether you were a single or double amputee. If you were a double, you could, at a given speed, at a specific mass, get into a helpful energy storage and return cycle (think of bouncing on a trampoline whereby you maintain height with minimal energy input). A single amputee couldn't get access to that effect at all. In both cases, anything above 100% was enhancing (and neither were) but the disparity was huge nonetheless. I do have some data regarding the shoes that I can't share yet as its under peer review for a journal other than to say, whilst there is clearly a gain, the gain isn't quite as groundbreaking when you look backwards over running over the last 50 or 60 years. The issue really is that people think that running as a sport is simple enough that records are retrospectively comparable. In my view they are not and never were.

2) My view is that the shoes should continue to be legal. There are philosophical issues such as the fairness access and cost but these are both short term issues. Nike's competitors are responding. Adidas arguably already has. The current rules are a little subjective though and may well need tightening up. However, this should not be aimed at Nike specifically - more so to remove the ambiguity that is currently in place.

The tricky issue is if they are banned will World Athletics remove the current world records ? Swimming did not do this and it took a few years (and arguably an Olympic cycle) to overcome. Not ideal. Likewise, the UCI did do this with the hour record for a while.... and it killed interest in it entirely. It's a poison chalice whichever way they go.

and, I think, in the US region.

 

I’m not sure about the headline in the Daily Mail. I think it’s click bate. There probably is a ruling coming out but I agree with the Science of Sport, it can’t be on the foam and plate. But let’s assume right now that they will ban the foam and the plate. Saucony Endorphin, Pbax and Plate, adidas Adizero pro, pbax and plate, Brooks looks pbax, New Balance Fuel Cell Race Plate no pbax. Nike Zoom Fly, plate no pbax. Most if not all are in some stage of commercialization. The shoes set to launch in Boston are on the water by February 1st. The shoes launching in June are in staging. The orders are placed with the factory which means the factory is buying the materials which means yes some money is being spent.

It’s also important to point out Kipchoge wore the shoes in Rio and Berlin so does that mean if they kick out the women’s world record, do they do the same thing for the men’s and do they remove the gold medal. I’d have to check but I think top 3 in Rio all had the prototypes on.

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Dave Jewell
Free Run Speed

End of Jan/beginning of Feb I've been told. The matter is so complicated, I've been led to believe that nothing you currently read in the press on the matter is true or known definitely.

Very cool Blue Ribbon Sports version!

This is the question that should be asked.

Y'all should stop freaking out or really caring about whether or not the IAAF bans these for the Olympics and other IAAF sanctioned races because they absolutely have no practical way of banning these shoes for amateur racing. it is just not possible, so Nike will still sell them, we will still run in them and if you think for one second WTC will ban them, you don't know WTC.

I didn't read the whole thread but did anyone talk about the surprising claim in the article that there is a health concern? I have never heard that before and think that may be the source trying to drum up the claim rather than an actual concern.

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808 > NYC > PDX > YVR
2024 Races: Taupo

That caught my eye too. That's an odd concern though given that in one of the published studies by Hoogkamer et al it was reflected on that the extra cushioning and particular design of the Nike's may actually decrease health risks not increase them. I've no idea where the health issue has come from.

One more thing, the other thing I'd add is that my support for the shoes is that they utilise energy passively. It's engineering excellence in how the energy is transferred into motion. Provided the energy contribution is passively based in nature (therefore it's energy return is liable to be less than 100%), a shoe could remain legal.

The access ethical argument though is a sticky area. Not all athletes have access to the shoe (just like Speedo swimsuits were back in '02) so it will be interesting if World Athletics share my view that this is a short term issue and other brands will catch up or (given that the Olympics is in a few months), suspend their use now and have a more through long term review, or just ban them outright. Bear in mind that when the Pistorius case was in full flow back in '09, the IAAF (as World Athletics were back then) got into a bit of a mess due to the pressures of time and dubious research. They may not want to repeat that episode again......

Nike Next% and 4% are the next Desoto Water Rover!!! Oh know!

its a bit silly, lets ban fast bikes as well, more buoyant wetsuits.

That's an astute point you made and if I were on their technical panel myself that's what I would be advising them too.

True story: When an official eventually actually got skewered by a javelin, the IAAF decided it was probably cheaper to shift the centre of gravity of a javelin rearwards then it was to lengthen the whole stadium ;-)

Ok then ban vapoflys. Last thing I need is a 4 percent increase in the length of the marathon. 26.2 is already a stupid distance that was lengethened to bring the finish in front of Buckingham palace for the first London Olympics...and now we are stuck with 26.2 miles versus 25. While Macca is happy for that extra mile and win over Ralaert at Kona 2010, the rest of us continue to curse the King of Great Britain for the bad location of his shack that lengthened the marathon.

I think most people would agree with a passive vs active energy use given that choice. But is passive sufficient to be fair? I would draw a line between 4 data points - a 'normal' racing flat, 4%, next% and Alphafly. Given that I'd say future, unregulated, shoes are lighter and taller. Some of the benefit comes from an increased stride length. Nike just happens to be able to do that in a light way that works nicely with a runners motion. The Alphafly is 50mm at the heel. Any taller shoe would also be passive from an energy perspective. So while I'd agree with the passive point, I'd say we also need additional regulations.

Thanks again for the discussion.

It was the queen.... and bless her heart, she did want to see the finish of the race without moving from her chair......

To be honest, the whole thing is a sham - for anyone who wants to know the distance from Marathon to Athen's, it's a damn sight longer than the 26 miles and change 'sprint' we have to run now ! ;-)