Starting out I would like to mention 3 pair of shoes, that are actually banned from competitions. I mean back of the pack runners can use it, but no elite or age group athletes are allowed to wear them.
- Spira – http://spira.com/
- APL – https://www.athleticpropulsionlabs.com/
- Enko – https://enko-running-shoes.com/en/
If I remember well the case, it is not actually the spring or the rebound itself what make these shoes illegal, but the loaded nature of the recoil technology. They are really propelling you forward.
In case of the Nikes, there is no tech like we can see in the sneakers mentioned above. The shoes propose energy return. The energy you invest into each stride will come back. It cannot give you more actually. If that carbon plate would be installed into the shoes on a way, that it stays under tension, then yes. That would be illegal, by current understanding of rules and regulations.
However, in my opinion that carbon plate in the Vaporfly is there, to bring the stride the closest to barefoot running. What do I mean? When you run efficiently barefoot, there is no energy loss. I mean, that there are natural energy-leaks, but you cannot do anything about it, as that is the nature of the movement. However, anytime, you increase the softness of the surface underneath the feet, that energy loss is increased. You sink in first, just then you accelerate. However, when running barefoot on hard surfaces, there is no sink phase and no lost time. The moment your feet touches the ground, your muscles contract to create an immediate recoil. Your inner propulsion is actually the best !
Here is a study, what concludes, that all shoed runs or walks have higher ground contact times, than anything barefoot. Actually, no study really needed, but to give credit to my thoughts: https://www.sciencedirect.com/science/article/pii/S1751616118309949
Why not run barefoot ?
I think, in totally ideal circumstances, like running on a 2mm thick medium soft or medium hard surface barefoot would result in the best ever times in case of a marathon. Have you ever run on a fresh and new running track ? If you did it in spikes, it feels like running in a medium cushioned shoe on the concrete ! It is still too much cushioning for as slow speeds as marathon running ! Not ideal for instance for a breaking 2 project !
There are many things to consider while running barefoot. Not only glass and syringes, but the texture and the temperature of the surface too. It messes up your feet big time. The human foot, because of the softness and the nature of the skin grips very well, maybe too well. That is no problem when walking and sensing the terrain for unevenness. However when running on totally even, flat roads, we don’t need that softness. We would need a thicker layer of protection in all parts of the skin.
Also the non absorbing nature of the concrete would hammer the crap out of the joints. Running on compact dirt might feel like cement, but it still has a little give. Just enough to make a huge difference. There is the evenness as well. I don’t think that humans are evolved to pedal forward stride after stride, while having the same impact on the same spot all the time for hours on end. Adjusting ground contact because of little bumps and changing angles on the road is a great way to stimulate muscles on a different way, but other muscles too.
The last thing to consider is the evolution of the foot in one single generation. If for 10 years of your life you were barefoot, than changed to a shoe wearing habit, most probably you wouldn’t have issues turning it upside down and going barefoot again at the age 20. You spent developing your body and brain in the most important phase of growth.
However when at the age of 12months your feet were already squeezed into shoes, what parents did not check for flexibility, fit and length, just for colour, the case if different. This is why we see only barefoot joggers, no real runners and most of those joggers injured ! It is not the lack of yoga, too much weight or bad technique necessarily, but a decade or 4, in a deformed and calcified body. Including the feet ! 40 years of bad posture and foot alignment, cannot be reversed by wearing five fingers for 3years !
For all the above reasons, we will not see marathon runners competing any major marathons barefoot, nor winning any of those. In case of a set up track, with the most ideal surface and softness, we might later on have somebody give a crack at a Sub 2, but I think it will happen in shoes and happen before barefoot.
( For the believers: There is an enormous difference between the 2:12 marathon of Bikila and a Sub 2 attempt. One is 3:07 pace and the other is 2:50/km pace.
For exemple, I am a simple runner of 35min 10km, however I am able to go through some 2:12 marathon workout paces. Not gonna be the case for a Sub 2 marathon, ever ! )
So, to come back to my initial thought about barefoot running and the Vaporfly. When added only the cushioning to the Nikes, they would absorb tremendous impact, they would protect your feet against the road and debris. However, the softness would absorb too much energy and would pull you down like you were running in hot tar. To balance out this mushy effect and the extra weight the carbon plate is added. So now you have a shoe what is the same springy as a racing flat (a bit closer to shoeless), but with enormous amount of cushioning.
Will they ban the Vaporfly ?
Highly doubt it. As I said, there is no propulsion device in the shoe. The spring might relieve some muscle work and help you get less fatigued, by offsetting the soft foam, but it doesn’t give you more spring. Just less not-spring, would I say.
You might say, that, yeah but the LZR suits got banned too in swimming. It did not make you faster, but more efficient. It is the same.
No, it is not ! Those suits made you glide more in the substance and gave you an unfair advantage, by reducing the drag by a whopping 24% ! It is like putting on a pair of shoes and you are suddenly lighter. Or applying a cream to have less air resistance, what is basically like running behind a pacer or pace car. Not the same !
Doping make you recover faster, making you run faster by helping you getting in more oxygen. In some cases to lay down new muscle fibres. To over stimulate you ! A double expresso helps you more, if timed correctly, than a Vaporfly ever will !
If they banned it, there must be a giant review of all running shoes in the market. Including all Mizuno shoes with their mechanical shock absorbers. All carbon shoes and carbon aided wins. Yes from like 7 years ago as an example, all races won by wearing the NB RC1600 , what had had already a carbon plate. Check videos and finish photos! Good luck with that !
All Carbon Rocket and Carbon X shoes. The Vanish R from Altra. Even track and cross country races to see, what track shoe’s spike plates gave propulsion. Salming R7 !
There is a hype behind the Fly, but in the last decade, there were at least 50 different models with carbon plates in them, if not more. Probably at least one of those had maybe even more of an efficiency effect than the Next% !
People are talking about shoes just to dismiss Kipchoge’s greatness. In my opinion he would probably be able to do all of these feats of endurance in the Streak or the Streak LT too. Who knows, maybe even better.
Vaporfly 196g vs. Streak LT 141g ! 55grams is enormous in case of shoes. The LT still has 18mm of forefoot cushioning and the 4mm drop would allow the runner to access more free elastic energy from the achilles tendon.
No, the Nike Vaporflies won’t be banned or at least not alone, but with other shoes together !
Personal encounters: I have a bigger, wider, higher than usual foot. US13 / UK12, wide and squared. Like it should be. The Vaporfly has a wide enough forefoot no problems, however the curve of the fore foot and the toebox shape make the shoe totally unsuitable for my feet. The thick cushioning makes my knees act up after a couple of strides. The stiff heel-counter annoys me too.
It might make me run better short term in case of speed, however probably would break me down, talking about posture and form. This is not my shoe.
The Carbon Rocket from Hoka is a lot more forgiving, lighter, less cushioned and with a 1mm drop, what reduces the need for excessive forward lean.
I am an Altra guy anyways. The comfort for any distance at any speed on any terrain is what I won’t sacrifice ever. Healthy feet, healthy body !