Alphafly

A near miss

On May 6th, 2017, three African distance runners lined up on the track of the Autodromo Nazionale di Monza in Italy. The Formula One arena had been carefully chosen as the location for Nike’s ambitious Breaking2 project due to its favourable running conditions, which the brand hoped would enable one of the athletes to do something unprecedented: complete a marathon in under two hours. The man who got closest that day was plucky Kenyan Eliud Kipchoge. He had already won multiple World Marathon Majors and was shaping up to be one of the greatest long-distance runners of all time, and despite falling short of his two-hour target by mere seconds, he and Nike still believed that it was an attainable goal; they just needed to refine their plan. In the months that followed, the pair worked in close collaboration to create an elite running shoe that could finally take athletes below the two-hour marathon mark. This groundbreaking piece of footwear was the Nike Alphafly.

The search for speed

Nike’s development of a high-tech distance-running shoe began in the mid 2010s, when the powerful combination of a carbon-fibre plate and ZoomX foam was discovered. The brand’s footwear engineers found that a midsole containing these two elements in the correct arrangement could propel athletes forward at great speed, and the innovation produced the Nike Zoom Vaporfly 4%, so named for its supposed ability to improve running efficiency by 4%. It was a prototype of this shoe that Kipchoge and the other racers had worn that day in Monza, with a general release following just a few months later.

Breaking records

Over the next two years, the Vaporfly series was responsible for a number of medal-winning performances in both men’s and women’s marathons, as well as Kipchoge’s 2018 world record, which he set at the Berlin Marathon in 2018, and Brigid Kosgei’s women’s marathon world record, which occurred at the 2019 event in Chicago. Kipchoge cut more than a minute off compatriot Dennis Kimetto’s 2014 time, finishing in 2:01:39, while Kosgei did the same to Paula Radcliffe’s 16-year-old record from the 2003 London Marathon, crossing the line in 2:14:04. Also from Kenya, Kosgei was in part inspired by Kipchoge, and as she took to the track in Chicago, she had an extra boost of motivation thanks to his most recent exploits, which had only occurred one day earlier at an event called the Ineos 1:59 Challenge. 

An extremely difficult task

Before the advent of the Nike Vaporfly, the question of whether or not any runner would ever go below the two-hour mark was hotly debated. Those such as multiple-medal-winning Ethiopian athlete Haile Gebreselassie, who himself held the marathon world record for a period of four years, suggested in 2011 that it would be possible within the next 20 to 25 years, while others like Kenyan long-distance runner Samuel Wanjiru, whose Olympic marathon record of 2:06:32 stood for almost 16 years, believed that no one would be able to go much below two hours and two minutes. Even researchers using scientific data based on trends in world record times theorised that nobody would run under two hours until somewhere between 2028 and 2040. Either way, the consensus was that the task was extremely difficult, if not impossible. None of this phased Eliud Kipchoge, though, and he turned up to the Ineos 1:59 Challenge on October 12th, 2019, with one thing in mind: becoming the first person to run a marathon in less than two hours.

A favourable location

The Ineos 1:59 Challenge was announced on May 6th 2019, exactly 65 years since English middle-distance runner Roger Bannister achieved the very first sub-four-minute-mile. Just a few months later, Kipchoge used this landmark and others as motivation in his attempt to make history at Prater park in Vienna; another course selected for its good running conditions. At that time of year, the weather is generally cool in the city, and the park is generally flat, with the route taking in just 2.4 metres of incline, meaning that no energy would be lost to changes in elevation. On top of this, the city is in a natural basin whose low altitude leads to high levels of oxygen in the air, and it resides in a very similar time zone to Kaptagat, Kenya, which is where Kipchoge had been training by running 124-140 miles per week, thus minimising any disruption to his sleeping and eating patterns during the event. Lastly, the tracks in Prater park are lined with trees that provide a natural shield against the wind so that Kipchoge would not have to fight against it as he ran. 

Optimising the conditions

Just like at Monza, Nike also optimised the conditions in other ways, recruiting a team of 41 pacemakers (35 main runners and 6 reserves) to assist its star runner. They were to be directed by green lasers projected onto the ground in front of them so that they would consistently go at the exact pace required for the Kipchoge to succeed. This elite team included some of the best athletes from across the distance-running spectrum, from former 1500m European gold-medallist Henrik Ingebrigtsen and his two equally talented brothers to Ugandan mountain running specialist Joel Ayeko and some athletes who had been part of the Breaking2 event, such as five-time Olympian Bernard Lagat. While those pacemakers had been arranged in a triangle directly in front of Kipchoge, the athletes at the Ineos Challenge ran in a V shape made up of 7 runners, with him at the base and two more situated at his back, each group rotating out at the end of every 9.6km lap of the course to make way for a new team with fresh legs. In front of this precisely structured formation was a car showing the projected time and beaming the pacing lasers onto the floor which itself acted as a barrier, thus enhancing the wind-resistant effects of the whole team. Meanwhile, carefully prepared drinks containing high levels of carbohydrates would be delivered by support staff on bicycles so as not to interrupt the race. These were part of a nutritional strategy that aimed to provide Kipchoge with the optimum amount of fuel to power his muscles from start to finish.

Enter the Alphafly

On the day of the run, thousands of spectators lined the course, giving a completely different atmosphere to the rather subdued feeling at Monza, where only members of the support team were present. Kipchoge himself had requested this change, believing that he would perform better in a race-like environment with fans cheering him on from the sidelines. He planned to set off at 8:15 in the morning, which was also thought to be the best time for getting a large audience while the temperature and humidity were still at a level conducive to running. On top of this, Kipchoge was supremely confident, saying that he had “no doubts” about beating the two-hour mark and speaking of “when” he would do so, not “if”. Other than his mental fortitude, perhaps the most effective tool at Kipchoge’s disposal was the pair of shoes on his feet: a prototype of the Nike Alphafly.

A key innovation

At the time, little was known about this mysterious shoe. Pictures of it had already appeared on social media the year before, but the images were grainy and it was unclear exactly how its design differed from that of the Vaporfly. However, come race day, the most important innovation of the Alphafly could clearly be seen on Kipchoge’s shoes through visible windows in the midsole. These see-through openings showed that, along with the ZoomX foam and the carbon-fibre plate, both of which had been used to make the Vaporfly an exceptional running shoe, the Alphafly had forefoot Zoom Air cushioning. Known for its powerful energy-returning properties, Zoom Air was the ideal third element in what Nike now calls its ‘system of speed’, acting as a springy pad to propel the runner forward with each step. In fact, the shoe had been built around this forefoot cushioning after the brand’s extensive testing showed that it provided the best energy return.

A remarkable run

With these powerful technologies beneath his feet, Eliud Kipchoge ran an incredible marathon in Prater park. In Monza, he had started quickly and finished slowly, and during his world record marathon, he had started slowly and finished extremely fast, but in Vienna, he started strongly and never let up, running each 5km section at a consistent pace of just over 14 minutes, before stretching out in the final two kilometres as he pushed to go under his target. On reaching the final 500 metres, Kipchoge began to speed up and the support team moved aside for him to come through and sprint towards the finish. The commentators described his running as “a gift to the world” and stated how they were “overjoyed” to see the great man achieve his goal. They even compared the moment to Neil Armstrong’s moon landing, Roger Bannister’s four-minute-mile and Edmund Hillary’s conquering of Everest as the crowd urged Kipchoge through the last 300 metres with deafening support. As he approached the line, he thumped his chest in celebration, looking like he could run another marathon, before crossing it in a time of 1:59:40.2. He was immediately embraced by his wife, Grace, who had never seen him run in-person before, while the commentators continued to praise him, one describing the run as a “masterpiece that will never be forgotten”. The team of pacemakers came in to congratulate him, lifting the great runner over their heads and cheering in celebration. When interviewed directly after the race, Kipchoge spoke of his desire to inspire people by showing them that “no human is limited” and that he now expected more people to run under two hours. He also paid tribute to the pacemakers, who were an essential part of the record, saying that they were “among the best athletes ever in the whole world”. 

Rumours and speculation

Following the Ineos 1:59 Challenge, athletes and spectators around the world were in awe of Kipchoge’s achievement, even though the artificial nature of the conditions meant that his time could not be counted as an official world record. It was, however, accepted by Guinness World Records, who labelled it both the “Fastest marathon distance (male)” and the “First marathon distance run under two hours”. This drew masses of attention, and many people became curious about the shoe he had worn to do it. Soon, rumours surrounding its design were circulating on social media sites and sporting news pages, some of which suggested that it had not one but three carbon-fibre plates and two pairs of Zoom Air pods stacked on top of each other. This mistaken notion arose from a schematic which was shared on the internet in the wake of the event showing one of many patents Nike had applied for during the making of the Alphafly. It was, however, not the shoe he had worn that day, as was confirmed by Nike’s VP of Footwear Innovation, Tony Bignell, who has since stated that it had just one; the same number as the general release version that came out in 2020.

Changing the rules

Bignell’s assertion was important in its timing, coming just after a World Athletics ruling which banned the use in official competition of any running shoe with more than one carbon-fibre plate. The ruling also restricted midsole height to 40mm as a way of controlling the power of the modern-day ‘super shoe’ and ensuring fair competition in future races. Fortunately for the brand, the Alphafly fit just within these boundaries, and since the updated rules only restricted prototypes as of April 2020, athletes competing at the United States Olympic Marathon Trials on February 29th could wear them during the event. In a surprising move, Nike decided to offer a free pair of Alphaflys to any athlete racing in the competition, not just those sponsored by the brand. Runners were under no obligation to wear the shoe during the event, but the fact that Nike had made the Alphafly available to everyone meant that nobody could claim unfairness due to limited access, as they had done with the Vaporfly. In December of that same year, World Athletics made further changes to its regulations around prototypes after several companies complained that they were unable to carry out proper testing of new models. This allowed the use of so-called ‘development shoes’, though only “by specific athletes at specific competitions” within a stated twelve-month period. 

An energy-returning foam

The secret to the success of the Vaporfly had been its clever blend of performance features, and the Alphafly was no different. In fact, it carried many of the same advanced running technologies as its predecessor. Most importantly, its midsole was made from ZoomX foam, which was responsible for a large part of the energy return athletes received as they ran in it. Nike first produced its specialised low-density foam in the 1990s, putting it into many of its cleats and other designs like 2000’s Shox R4 running shoe. Over time, the specific formulation of the foam was adjusted to suit different types of shoe, and in the Alphafly, it was optimised to be highly responsive. In fact, a 2018 study revealed its amazing energy-returning properties, stating that, while EVA returns around 66% and TPU 76%, ZoomX foam gives 87% of the runner’s energy back to them with each step. As well as being powerfully springy, the Alphafly’s ZoomX foam was also soft, supportive, and lightweight, which allowed Nike’s designers to create a tall, chunky midsole that could both store and return far more energy than its rivals without adding excess weight.

A stabilising plate

ZoomX foam was a major factor in the function of the Nike Alphafly, but it would have been far less effective had it not been for the full-length carbon-fibre plate running through its centre. It was Nike’s competitor, adidas, who had first discovered the power of adding such a plate to a running shoe while working with researchers at the University of Calgary’s Human Performance Lab in the late 1990s. A student of one of those researchers named Geng Luo eventually brought the idea to Nike when the brand hired him in the early 2010s, and it was this that led to the Vaporfly’s revolutionary carbon-fibre plate. However, it wasn’t as simple as just putting this plate inside the midsole, the feature had to be carefully engineered to ensure that it helped and didn’t hinder the runner. With time and testing, Nike’s footwear experts sculpted the carbon-fibre plate into a spoon-like shape that guided the foot naturally through each part of the step while also transferring the forces acting upon it towards the forefoot to propel the runner on with each step. In addition, it had a stiffening effect which counteracted the inherent lack of stability and coordination in the soft ZoomX foam, thus imbuing the Alphafly with both of these essential characteristics. When the carbon-fibre plate was first introduced, it was thought to be the main component behind the revolutionary springiness of the super shoe, which is part of the reason why it was eventually limited by World Athletics. However, it turned out to have more of a stabilising effect, controlling and directing the energy return produced by the ZoomX foam so that it was provided to the runner at exactly the right moment: when they pushed off from the forefoot. It was at this point that the third part of Nike’s system of speed, the Zoom Air cushioning, came into its own.

Responsive cushioning

Like ZoomX foam, Zoom Air had been around since the 1990s, but Nike has always tinkered with its advanced cushioning technology to maximise its effects in each specific shoe. For the Alphafly, this meant putting two circular pods on either side of the forefoot, where they could provide the kind of resilience and responsiveness required to power runners over long distances. During a run, the front of the foot carries a lot of the load as it is the location from which the athlete launches themselves into the next step. By placing Zoom Air cushioning in that exact place, Nike both protected the runner from road impacts and provided them with extra energy return at the time when it was most needed. Indeed, it has been found that Zoom Air, with its springy tensile fibres, offers more than 90% energy return to the wearer, hence the remarkably propulsive feel of the Alphafly.

A lightweight upper

Each one of these high-tech components was crucial to the groundbreaking speed of the Nike Alphafly, but it was together that they were so powerful. The ZoomX foam cushioned the footstrike, collecting and storing energy from the runner to return back as they transitioned into the next step, the carbon-fibre plate stabilised this whole process by guiding the foot forwards into a position where it could maximum power and speed, and the Zoom Air pods delivered a final burst of energy return to drive the runner onwards. This elaborate structure wasn’t the only reason the Alphafly was so quick, though, it also had an advanced upper made from a version of Nike’s tough but lightweight Flyknit material known as AtomKnit. Even lighter than earlier versions, AtomKnit was highly breathable and absorbed very little water, while its flexible nature offered a contoured fit and great containment around the foot. With this final comfort-giving, weight-saving component in place, the Alphafly was the complete running shoe, and over the next few years it came to dominate the competitive landscape.

Insightful data

Eliud Kipchoge remained a huge part of this dominance as he proved his outstanding abilities again and again in the early 2020s. More than this, though, Kipchoge’s rigorous training schedule and elite athleticism helped Nike to hone the design of its premier running shoe over time, which in turn was good for the Kenyan marathoner, who later declared that he wanted the Alphafly to be a part of the legacy he would leave for future runners. From his training base in Kaptagat, he stayed in close contact with the brand, feeding back data about his daily runs and writing his own personalised notes to supplement their research. The two met together several times a year, both on video calls and in-person, with Kipchoge becoming an integral member of the development team. As well as the information gleaned from his training, Nike also benefited from being able to analyse his competitive races, both the good and the bad. Unfortunately, 2020 was in the latter category as Kipchoge recorded his worst ever marathon placement of 8th at the London Marathon. Like all other athletes at the time, he was hampered by the global Covid pandemic, but better times lay ahead as the veteran runner defended his Olympic title at the delayed Tokyo games in 2021, winning by a huge margin of 80 seconds – the biggest in almost half a century – making him one of the oldest men to win the event. 

Improving the Alphafly

Using the raft of information gained from Kipchoge, as well as the rest of his racing team and hundreds of other runners both professional and casual, Nike was able to improve the Alphafly for its second iteration. The aim was to give the model even broader appeal by increasing its already exceptional efficiency through a precise balance of cushioning, propulsion and weight that would help all runners to improve their performance. Since the original design was so effective, this only involved small changes, such as widening the base for greater stability and thinning the outsole to allow room for a fine sliver of ZoomX foam beneath the Zoom Air pods. This brought about a smoother transition through the foot and increased energy return, while the bigger heel drop of 8mm as opposed to the previous 4mm encouraged the runner to lean forwards and make the best use of the Zoom Air cushioning in the forefoot. A little extra padding was added around the heel and over the top of the foot, and the updated AtomKnit 2.0 upper gave a more comfortable fit along with better breathability. The powerhouse combination of ZoomX foam, a spoon-shaped carbon-fibre plate and forefoot Zoom Air pods was otherwise unchanged, giving the Alphafly 2 the same ultra-responsive feel as its predecessor.

A new world record

Though small, these adjustments delivered significant results, and Kipchoge excelled in the Nike Alphafly 2. He began 2022 by announcing a bold aim: to win all six World Marathon Majors. Having already ticked London, Berlin and Chicago off the list, he turned his attention to Tokyo, where he set a new course record of 2:02:40 on his way to a magnificent victory. However, one of the most remarkable moments of Kipchoge’s career came just a few months later, when he attempted to win the Berlin Marathon for a fourth time. Arriving at the venue, which is known as an excellent hunting ground for those seeking to break marathon world records, Kipchoge could be seen wearing a bright orange colourway of the new Nike Air Zoom Alphafly Next% 2 (Nike had removed the specific 4% moniker by this point as it was believed that the efficiency could be increased by even more in certain runners). The conditions were almost perfect for marathon running, and Kipchoge set an incredible pace through the first half of the race. He ran it so quickly that he even went three seconds under the time registered during his Ineos Challenge marathon, leading onlookers to speculate that he may actually do the same here in a genuine race setting. However, his splits then dropped off, and it became clear that this wasn’t the moment. Nevertheless, he still looked like going under his world record time, and by the 30km mark, he was running alone with only the clock to beat. Despite slowing in the second half of the race, he had the energy to sprint the final 500m, coming in at exactly 30 seconds below his previous world record time at 2:01:09.

The science behind the shoe

Thanks to Kipchoge’s record-breaking antics, the Nike Alphafly 2 was hugely popular in 2022. Its performance fascinated scientists, leading some to conduct research projects to discover why it was so effective. One study carried out at the St. Edward's University in Austin, Texas, found that the Alphafly had the best running economy on average when compared to its closest competitors, even outperforming the Vaporfly, which came in a close second. The research revealed that, when wearing the Alphafly, the participants produced the longest stride length and had a strong, fast, bouncy step, with those who put the most into it also getting the most out of it. In fact, it was found that some runners could get an efficiency improvement of around 6%, though the exact amount was dependent on things like arch shape, foot width and gait. Nevertheless, this synergistic effect made the Alphafly 2 exceptional as a competitive shoe, as did its ability to reduce stress on the legs and joints, which allowed runners to keep pushing hard during the latter stages of a race. It also reduced recovery time between races, giving runners the opportunity to fit more events into the racing year. Meanwhile, Wouter Hoogkamer at the University of Colorado did tests on the carbon-fibre plate, showing that its stiffness augmented the work of the foot. He also demonstrated how the shape and geometry of Nike’s patented Flyplate worked in concert with the foam to generate power, stability and speed.

The Nike Air Zoom Alphafly Next% 3

By 2023, Nike had already started work on its next Alphafly design, which due to rising competition from brands like adidas, who had produced a shoe worn by Tigst Assefa as she smashed Brigid Kosgei’s women’s marathon world record by over two minutes at the Berlin Marathon, would need to be seriously good. The Nike Alphafly 3 turned out to be exactly that. Through a series of adjustments based on extensive data taken from all types of athlete, including the largest-ever pool of women to be tested for a Nike racing shoe, the Alphafly 3 took performance running to new heights. Its large sole unit was filled with stacks of ZoomX foam that maximised the 40mm height limit set by World Athletics. Its continuous lower section connected the cushioning in the forefoot and midfoot for the very first time, thus enhancing the running experience by improving the heel-to-toe transition for those with different footstrike patterns. The Zoom Air units remained in place, as did the full-length carbon-fibre Flyplate, though it was slightly wider than before, and therefore even more stable. It also had a more lightweight and equally grippy Fast Shot outsole, and its upper was made using the latest AtomKnit 3.0 mesh for enhanced lockdown, breathability and midfoot support. An integrated lacing system with additional padding reduced lace pressure, and lofted Flyknit Pods on the heel cushioned the back of the foot while also protecting the Achilles from injury. The shoe was also produced using a different last shape that delivered better comfort through the arch of the foot and reduced rubbing, with a moulded sockliner supporting this new low-profile arch.

A new marathon champion

Even before the Alphafly 3 had been released to the public in January 2024, it was already making headlines in the world of distance-running as Nike put a test model known as Dev 163 through its paces during the official development window allowed by World Athletics. The advanced design, Kipchoge won a record 5th Berlin Marathon title in another fast time of 2:02:42 despite being almost 39 years old, but it was the exploits of another Kenyan runner, Kelvin Kiptum, which really stood out. Kiptum had already shown his marathon running credentials on his debut at the 2022 Valencia Marathon, where he shocked everyone by running the fourth-fastest time in history and breaking the course record by more than a minute. At this point in his career, Kiptum favoured the Nike Vaporfly 2, which he wore as he took another remarkable victory at the 2023 London Marathon. Here, he went even quicker than in Spain, beating Kipchoge’s course record by over a minute and finishing in 2:01:25 – a mere 16 seconds behind his compatriot’s world record time.

A record-breaking shoe

Following these two unbelievable performances, Kiptum arrived at the Chicago Marathon in October 2023 with the Nike Air Zoom Alphafly Next% 3 development shoe on his feet and high expectations on his shoulders. In favourable conditions, he started at a good pace, leaving most of the other runners behind by the 15th kilometre. He went through halfway considerably faster than he had in London, but was still short of the pace required to break the world record. However, in his short career, Kiptum had developed a reputation for getting faster towards the latter stages of the race, and he did so again, powering away after 30 kilometres to record an outstandingly quick negative split over the next 5km. The closer he got to the finish line, the clearer it became that he was going to do it, and so he did, winning in a time of 2:00:35. It was the first marathon in which anyone had gone below two hours and one minute, and he was just seconds away from averaging 21km/h across the whole race. After his victory, Kiptum stated that he had been free of pain throughout, just like in his other marathons to that point, thus showing the incredible support he was receiving from Nike’s super shoes. Meanwhile, in the women’s race, Dutch runner Sifan Hassan showed that the Alphafly was a great female running shoe as well, winning in a course record time of 2:13:44, which was the second-fastest women’s marathon up to that point.

The Paris Olympics

The Nike Alphafly 3 was released to the general public in January 2024, with both amateur and elite athletes keen to get their hands on the shoe to see if it could help them beat their own personal best times. Throughout the year, it excelled at the top level and was lauded by some as the fastest marathon shoe at the Summer Olympics in Paris. While the advent of the super shoe had seen world records broken in both the men’s and the women’s event multiple times since Kipchoge’s 2018 effort, things had remained more stable at the Olympics. The women’s record had been in place for 12 years and the men’s 16, each being made in Nike running shoes that predated the era of the carbon-fibre plate. However, that all changed in 2024, when both records fell. While the men’s race was won comfortably by Ethiopian reserve runner and adidas athlete Tamirat Tola after Kipchoge had been forced to drop out part-way through, the women’s race was an unpredictable drama involving two of the best female distance runners and two of the best running shoes of the time.

Two exceptional athletes

In some ways, the women’s marathon in Paris represented the battle between modern super shoes. While it’s clear that the runner is the most important factor in any victory, for Nike, it was crucial that the Alphafly demonstrate its power by coming out on top, especially since an adidas athlete had won the men’s race. Nike’s top female representative was Sifan Hassan, a versatile Dutch runner who had already held world records for the one hour run, the one mile track run and, for a very brief period of two days, the 10,000m. She had also impressed at the last Olympic Games in Tokyo, winning golds in the 5,000m and 10,000m, as well as a bronze in the 1,500m, something which had never been done before by any Olympic athlete. She was in good form as well, having triumphed at the London and Chicago Marathons in 2023. Earlier in the tournament, she had achieved bronze medals in the 5,000m and 10,000 metres, but her stated priority was the marathon, which took place on the final day of competition. Her biggest challenge would come from the world record holder herself, Tigst Assefa. Also in great form, the Ethiopian distance runner had surpassed Kosgei’s 2019 world record by two minutes and eleven seconds at the 2023 Berlin Marathon, finishing in 2:11:53. Notably, this was almost two minutes quicker than Hassan’s personal best of 2:13:44, possibly giving Assefa the mental edge over her.

A dramatic race

When the two fastest female marathon runners of the time lined up next to each other on August 11th 2024, both were full of confidence and at the height of their powers. The course ahead of them was one of the most challenging in the history of the Olympics, with over 400 metres of elevation and descent, and took place in the hot, humid summer of the French capital. After halfway, Assefa was at the front of the lead pack, while Hassan lagged just behind. As the course progressed, more and more runners dropped off, leaving just five as they passed the 38-kilometre mark. With just a few hundred metres to go, Hassan and Assefa were left together at the front, and both began to sprint for the line. After going shoulder to shoulder in a tense moment, Hassan pulled away to win by just three seconds. She had set a new Olympic record of 2:22:55 and made even more history by becoming the only female runner to achieve Olympic gold in the 5,000m, 10,000m and marathon.

Ruth Chepng’etich

At this point, Nike athletes held the world record for the men’s marathon and the women’s Olympic marathon, while adidas runners were in possession of the women’s race and the men’s Olympics. However, the Nike Alphafly 3 was not finished yet. At the 2024 Chicago Marathon, conditions were ideal for a fast race, and Kenyan athlete Ruth Chepng’etich was determined to put in a strong performance, especially since she had been left out of the Kenyan Olympic team earlier that year. Having already emerged victorious at the event in 2021 and 2022, she was looking to come back from a 2023 race in which she had lost the title to Sifan Hassan and her prototype Alphafly 3.

Another remarkable victory

Before the Chicago Marathon began, a poignant moment of silence was held for Kelvin Kiptum, who had sadly passed away earlier in the year, meaning that he would never be able to challenge for a two-hour marathon. Inspired by his memory, John Korir ran the second-fastest time ever in the Chicago event to win the men’s race, setting things up nicely for the women’s race. From the start, Chepng’etich went out extremely quickly, vying for the lead with Ethiopian Sutume Asefa Kebede, who had stated her intention to set a strong pace early on. Kebede had planned to pass halfway in 1:05:30 and ended up doing so a full minute faster, but Chepng’etich was already 14 seconds ahead of her. The Kenyan only proceeded to increase her lead throughout the second half of the race, pulling further and further ahead of Kebede and the other runners. Even though she slowed towards the end, Ruth Chepng’etich became the first woman to go under 2:11 and 2:10 in the marathon, beating Assefa’s 2023 record by almost two minutes with an astonishing time of 2:09:56 and proving the awesome power of the Nike Alphafly 3.

A history-making shoe

Today, the Nike Alphafly stands out as one of the greatest running shoes in marathon history. It has formed incredible partnerships with some of the fastest athletes in the world and been responsible for multiple distance-running titles and world records. However, it is not simply a shoe for elite runners; it has also brought speed and style to runners of all levels, who have been able to challenge their own personal best times and set more ambitious goals than they ever thought possible. With Nike’s continued push for athletic excellence driving innovation and athletes like Eliud Kipchoge inspiring runners to go beyond their limits, the next Alphafly could yet surpass the achievements of its forebears and make even more sporting history.