In the late 1980s, just before US basketball hype hit the rest of the world, sports shoe maker Nike shot a few commercials starring Spike Lee. In it, Lee watches the century basketball player Michael Jordan play. The slightly ironic message of one of the clips: If you buy the shoe model of Jordan, then maybe you can play better basketball. But nobody can play like Michael Jordan. It is not the shoes.
If Nike were shooting a similar clip with the century-runner Eliud Kipchoge today, the Oregon company would certainly choose a different message. It is the shoe that makes the Kenyan so fast.
Kipchoge is one of the greatest runners of all time. He has not lost a race for years. A few days ago he ran a marathon in Vienna as the first man under two hours, but the record is not recognized by the International Athletics Federation IAAF. Because it was not an official race but to some extent an experiment in which everything was done to create perfect conditions for Kipchoge. During the 42.195 kilometers, for example, he was constantly running in the lee of alternate leaders who could rest after each lap.
Nevertheless, Kipchoge was acclaimed at the finish for his performance. However, especially competitors from regular races might have looked with suspicion on Kipchoges feet. There were white and pink running shoes from Nike.
About the shoe and also the predecessor model is discussed not only since the record run among athletes and sports scientists. Now, the IAAF Technology Commission has announced an investigation because athletes have complained about contracts from other suppliers. They sense a competitive advantage for the Nike runners.
more on the subject
In fact, the Nike Vaporfly has boosted the running world. Recently, several road-long-distance world records were broken with the shoe. Kipchoge himself holds the official marathon record with a time of 2:01:39 hours, set up in Berlin. In the women's race, Kenyan Brigid Kosgei beat Paula Radcliffe's 16-year-old record this year in the Chicago Marathon with those shoes on her feet. And the half-marathon mark also fell in September by Geoffrey Kamworor - of course he ran in Nike shoes.
What is the secret of the miracle trager?
The Vaporfly and the successor alphaFly, which is now worn by Kipchoge, have a strange look for competition shoes. With their voluminous sole they do not look like a fast shoe for top performance. Nevertheless, they are very light with well under 200 grams. And independent studies and studies attested to the technique of vaporizing an advantage.
A big data analysis of race results on the training platform "Strava" came to the conclusion: Who carries Vaporfly, running the marathon between three and four percent faster than other athletes in comparable performance classes. The addition Vaporfly 4%, with which Nike markets the model, seems to be correct. Runners save a few percent of energy through the shoe, and the running economy is improved
Kipchoge with Nike shoe: In the prototype of the record run, an air cushion is incorporated
This is partly due to a midsole made of carbon fibers, which is invisible incorporated in the shoe. Their effect is based on the following principle:
During the rolling movement of the foot, the toe joint is stressed by runners, the toes are slightly bent backwards. Experts speak of a Dorsalflektion. This mechanism helps to destroy a small amount of energy in each step of a runner in the toe joints. "Due to the bending motion, some joules lose their energy," says biomechanics expert Gert-Peter Brüggemann. The hard sole is a strategy that works against this mechanism. It stiffens the toe joint, the toes do not move anymore, less energy is lost with each step.
The plate in the shoe has a disadvantage. Because of the stiff element in the sole lengthen the lever, the Achilles tendon and the calf muscles must do more. Here are the biomechanical and physiological benefits of East African runners come into play: they have genetically not only a slightly longer heel bone and thus more favorable leverage. Even her Achilles tendon, which is instrumental in the repulsion movement, is thicker and longer. "That's why a runner like Kipchoge can handle such a shoe," says Brüggemann. A Central European runner would have to muster more strength at this point, he usually has a slightly shorter and often thinner tendon.
iStockphoto / Getty Images
Cheaper leverage: showing a foot with heel bone (left) and Achilles tendon
In the long term, such a shoe could even be customized to the runner by varying the stiffness of the plate. "That's basically a kind of gear shift in the shoe," says the emeritus sports scientist from the Sport University Cologne.
Technique trick uses muscles more efficiently
Brand new is the technique with the stiff and lightweight carbon sole not. It has already been used in shoes for sprinters. "Usain Bolt also walked in shoes that strongly stiffened the toe joint," says Brüggemann. Nike has now brought the technology to the long haul. Meanwhile, the manufacturer Hoka uses carbon for one of his models.
A second factor in the shoe is a soft and light material in the back and midfoot. This resilient plastic is very well deformed when the runner occurs. Then there are large parts of this deformation energy back to the runner back. "In this way, less muscle can be used per step, especially in the large extensor muscles of the legs, to produce the same propulsion," says Brüggemann.
That's like the pole vault, he explains. The athlete releases energy to the staff in the first phase of the jump as it bends. When the athlete gets stuck in the air, he slows down a bit, his muscles are not working so fast anymore. From studies, researchers know that he can then muster more power in this phase to pull himself up the staff. At the end of the movement, he gets the energy back from the bar - the athlete is catapulted over the bar. "In this way, a technical trick will make more efficient use of the muscles and improve the running economy," says Brüggemann.
Such technology is also in other shoes. But apparently, Nike's team with Geng Luo, who has even been honored in a Science article, found a particularly favorable combination of technique and material. On the long-haul, the fight increases by seconds. About 500 joules of energy are consumed by such runners per step. Just a few percent of energy savings makes a difference, especially in the top category of marathons.
That athletes who are under contract with other shoe manufacturers and need to run their shoes with envy to look at the Nike runners is understandable. This envy drives partly strange flowers: In the Dubai Marathon, the Ethiopian Herpassa Negasa secretly started in Nike-Tretern, although he is under contract with Adidas. He had painted the Vaporfly pretty bungled with an Adidas look so that the dizziness did not fly. Negasa finished second and improved his best time by several minutes. Nevertheless, his sponsor should not have liked it.
This is awkward! Herpassa Negasa who was a 2:09:14 runner, today runs 2:03:40 for 2nd at the Dubai Marathon. He is wearing an Adidas uniform but the Nike Vaporfly 4% painted over. ♂️
Shoes are worth risking it all for! pic.twitter.com/iWUYVXmHe3
Such actions fuel the discussion about equal opportunities in running and whether high-tech footwear offers an illicit advantage. According to the regulations of the Athletics Federation, a shoe must be freely accessible to all athletes and must not offer any unfair advantage.
Also sports scientists demanded a regulation several times - so far without success. In a recent article in the British Journal of Sports Medicine, sports scientists Geoffrey Burns and Nicholas Tam proposed to regulate the thickness of the midsoles - at least in competitive shoes. Burns, who himself ran marathons well under two and a half hours, argues that such a unified standard could be created.
How the athletics association will decide in the case, is not yet in sight. One thing is certain: the shoe is a passive element, it does not generate any energy. Kipchoge and Co. still have to run themselves. But the discussion about technical achievements is reminiscent of cases from other sports, where the relevant associations intervened: In table tennis, adhesives were banned, which give toppings more spin and speed. At some point, swimmers were no longer allowed to compete in energy-saving high-tech body suits. And in road cycling no Profirad may weigh less than 6.8 kilograms, although that would be easily possible through lightweight carbon parts.
Nike is happy about the discussion. Better advertising for the shoe should not exist. It is not cheap, however. With almost 280 euros, it costs almost twice as much as an average running shoe.
The vast majority of amateur runners can still save the money. The shoe will not do you any good. It is a pure competition shoe, designed for very light and fast runners and straight stretches. For heavier average runner he is completely unstable.