 This is the shoe that Nike claims can make any runner 4% faster. This is the Vaporfly 4%. With them, Yulid Kipchogi ran the fastest marathon time ever in just under two hours and many credit this feat to these shoes, dubbing the phenomenon mechanical doping. But mechanical doping isn't anything new. So how would we get here and what are these shoes really capable of? The term mechanical doping came about in the early 2010s in the world of cycling. When many accused Tom Boonen, a Belgian elite cyclist of having an electric motor hidden in his bike, after he was able to climb a steep section of the Tour of Flanders while remaining seated as opposed to standing up off the seat. For the next few years, various cyclists accused others of similar tactics and the Union cyclist say Internationale, the body that governs international cycling competitions, even started inspecting bikes prior to many international races. Nearly six years later, the first pro cyclist would be caught with a secret motor hidden in his bike, which would lead to even closer scrutiny of cyclist bikes. In this case, the mechanical part of mechanical doping is obvious. The use of a motor to give cyclists extra power over the competitors is a clear and unfair advantage, as an external object is acting on the cyclist, improving their performance. The mechanical doping isn't always this clear cut. In 2008, an Italian company working in conjunction with NASA released a new racing swimsuit, marketed as the world's fastest swimsuit. It was modeled after SharkScan to reduce friction on the swimmer by 24% and provide extra forward force as they swam. It may sound like a lot of hype, but at those 2008 Olympics, 23 of the 25 world records broken were achieved by swimmers competing in this LZR swimsuit. And further testing indicated that the suit reduced competitive swimmers' times by about 2%, which doesn't sound like a lot, but at Olympic races, it's not uncommon for three or more swimmers to finish within a second of each other, so that 2% can be the difference between coming in first and not placing at all. The suit clearly gave an advantage over swimmers who weren't wearing one, but it's harder to say if it's an unfair external advantage, like in the case of the hidden motor. Shortly after those 2008 Olympics, the Federación Internacional de Natación banned the use of full body-length swimsuits, preventing the new suit from being used again. So what does this all mean for Nike's Vaporfly? First off, how does the shoe actually work? You know the squishy part at the bottom of your running shoe that helps push you off the ground? Well, the Vaporfly uses a new type of phone called Pebex, which is 87% efficient in translating your downward pushes into forward momentum, compared to about 65% for traditional running shoes. On top of that, the Vaporflies include a carbon fiber plate embedded into the foam. With all the extra foam without the plate, wearing the shoes would be like running on snow and actually dampen your strides, making it much harder to run. The carbon fiber plate helps the foam compress and expand quickly, propelling you forward with each step, and the plate is curved upward towards the front of the shoes, meaning that the runners are rocked forward from their heels to their toes more quickly, so they can push off again faster. Over the course of a 2-hour marathon, that 4% speed would count for about 5 minutes. And considering Koshogi finished the 2-hour marathon with just 20 seconds to spare, those 5 minutes can be the difference between a world record time and falling short. Vaporfly, if you can get them, are sold for $250, meaning they're within reach for even casual runners. This is the first time that mechanical doping has really been available to the general public, and it's raised questions about the very purpose of sport. Some say that the shoes provide an unfair advantage, giving runners extra speed beyond what runners would have historically had access to. While others say this is just the latest progression of sport, as humans try to push themselves to the very limits of what's possible. No different than similar advances in dietary and training technologies that have seen similar lifts in world record times. Following a lot of public comments on both sides, officials at the World Athletics Organization narrowly avoided banning the vaporflies in international competitions, but imposed new rules regarding the thickness of shoe soles and limiting shoes to one plate. As technology continues to develop, and athletes seek to push their limits even further, we're likely to continue to have to grapple with accessories like these that raise the question of fairness in sports. At least for now, it appears the vaporfly is here to stay. But what do you think? Is wearing them like wearing any other shoe, or are they unfair to the athletes' records that came before? Let us know what you think down in the comment section below. Make sure to subscribe and turn on notifications so you never miss an upload. And remember, there's always more to learn.