Fresh approach to refuelling, technological advances and more aggressive training philosophies will likely lead to even more historic feats
Uganda’s Jacob Kiplimo – seven world records in one week: the three reasons why best times keep tumbling
Uganda’s Jacob Kiplimo set a world record in the men’s half-marathon, shattering the previous best by 48 seconds Credit: Gregorio Borgia/AP
Seven world records by five athletes hailing from four different continents in the space of only eight days.
The reawakening of athletics following the Olympic summer has been spectacular, culminating on Sunday: a world record in the men’s half-marathon by Uganda’s Jacob Kiplimo of 56min 42sec that shattered the previous best by 48 seconds.
It was the biggest half-marathon world record improvement and, with Kiplimo making his debut over 26.2 miles in London on April 27, a first official sub two-hour marathon looks feasible. Elsewhere over the weekend, Japan’s Toshikazu Yamanishi lowered the 20km race walk record to 1h 16min 10sec, while the American double Olympic medallist Grant Fisher took the men’s indoor 5,000m world record down to 12min 44.09sec. Fisher had also set a 7min 22.91sec 3,000m world record at the Millrose meeting in New York the previous week when Yared Nuguse lowered the mile record to 3min 46.63sec. That mile record, however, would last only five days, with the Norwegian Jakob Ingebrigtsen taking it down to 3min 45.14sec on Thursday night while also beating his own 1500m mark en route in 3min 29.63sec.
Keely Hodgkinson was also confident that the women’s 800m world record would have fallen on Saturday had it not been for a hamstring tear just 72 hours earlier. So what are some of the factors which lie behind this glut of world records and will it continue?
A simple glance at the list of athletics world records underlines one of the biggest factors in all this. From the road mile upwards on the men’s side, and in the 1500m and above in the women’s, every single world record has been set since the emergence of what are now known as “super shoes”. The first prototypes were seen at the 2016 Olympic marathon in Rio de Janeiro, when Nike runners dominated the men’s podium.
The first mass-market version was then the Vaporfly, for which tests showed a four per cent increase in efficiency. An arms race soon ensued, both on the road and with track spikes, to produce ever lighter and more responsive shoes. Although the feeling inside athletics is that the big seismic shift has already happened, there are new models each year and every shoe company is now trying to better customise their shoes to the running style of specific athletes. The shoe’s weight is also an ongoing focus. The £450 Adidas Pro Evo 1, for example, weighs in at just 138 grams.
A close-up of Kelvin Kiptum’s shoes after he set a marathon world record in Chicago in 2023
The late Kelvin Kiptum set a world record in the 2023 Chicago Marathon in these Nike Alphafly 3 shoes
Most super shoes have some sort of curved plate or rods inserted in the foam midsole (usually made of carbon) to maintain their shape and promote an optimum rocking motion. Most super shoe models also use a midsole material called Pebax and, although people assume that the carbon element is crucial, most of the energy is actually optimised in this foam.
The heel limit on road shoes is 40mm – and the biggest improvements have been on the road – but we are also now seeing much more responsive track shoes up to the legal 20mm limit, with Nuguse, Fisher and Ingebrigtsen all wearing either the Nike Dragonfly or Victory spike. Kiplimo set his road half-marathon record in the Nike Alphafly 3 shoe that retails at £289.99 and was also worn by Ruth Chepngetich and the late Kelvin Kiptum for their marathon world records.
A less publicised but equally competitive field of research just now in endurance relates to fuelling. Issues around digestion have long since limited what athletes can ingest before and during competition, whether that is in simple carbohydrates or sodium bicarbonate, a performance enhancer for the way that it allows athletes to maintain their intensity during moments of extreme exertion.
The Swedish company Maurten designed a hydrogel some years ago that could bypass the gut while ingesting carbohydrates, meaning that athletes can potentially absorb more fuel while exercising than previously thought possible.
Maurten then used this technology to see if sodium bicarbonate could be delivered in a more effective way after a large proportion of those trying simply to ingest what is essentially baking soda found themselves requiring multiple toilet trips.
The results of their “bicarb system” have been extraordinary and, rather like Nike with the super shoes, other companies are now trying to develop their own versions. The vast majority of leading middle- and long-distance runners now use sodium bicarbonate, a product described as “gold dust” to the Telegraph by one leading coach. Trevor Painter, who coaches Hodgkinson and Olympic 1500m bronze medallist Georgia Bell, says that he “couldn’t recommend Maurten bicarb strongly enough”. Sodium bicarbonate is believed to be beneficial during strenuous exercise of more than about a minute because of the body’s production of hydrogen ions and lactate salt.
Hydrogen ions make muscles and blood more acidic – thus decreasing efficiency – but the working theory is that the sodium bicarbonate helps to “flush” those hydrogen ions out more quickly. There is also a belief that the lactate itself is moved more rapidly and can thus be used as a fuel. Sports scientists believe the significant benefits stretch from distances of 800m all the way up to the marathon and beyond.
Keely Hodgkinson and coach Trevor Painter during a strength and conditioning session during a winter training camp in South Africa in January 2024
Keely Hodgkinson with coach Trevor Painter, who advocates ingesting a form of sodium bicarbonate to improve performance Credit: Michael Steele/Getty Images
Training smarter
In understanding the impact of changes in shoe technology and fuelling, it is critical also to look beyond any individual race to the new training possibilities that might arise.
The British runner Chris Thompson, whose distinguished career straddled before and after these innovations, reckons that super shoes moved marathon times forward by an average of four minutes but says that “learning to train” with them has become an art in itself. Although some runners report calf issues with excessive use, the general consensus is that recovery from more intense sessions is quicker and thus greater volumes of training are possible.
“I’m coming back after two days and doing stuff that I think shouldn’t be possible,” said Thompson before finishing in the top 10 of the 2023 London Marathon, aged 42. Anecdotal stories of Kiptum running up to 300km a week soon spread inside athletics and a general move back towards a higher-volume ethos is evident. That is not just down to the shoes or fuelling, however, and it is clear that the extraordinary success of the entire Ingebrigtsen family – but most notably double Olympic champion Jakob – is having a big knock-on through the sport.
Similar to Tadej Pogacar in cycling, they employ a training mode that emphasises tightly controlled “threshold” training at a 7/10 sort of intensity in order to help accumulate vast quantities of kilometres without excessive fatigue. It is a general philosophy followed by Fisher and now Great Britain’s George Mills, who has just smashed Josh Kerr’s national 3,000m record, as well as the Swede Andreas Almgren, who recently set a European 10km road record. A previous emphasis in the 1990s and 2000s towards higher intensity but lower volume training still suits some – especially over 800m – but a greater proportion of athletes now seem to be staying free of injury and consistently reaching their potential.
Action shot of Scottish athlete Eilish McColgan competing
Eilish McColgan suggests shoe technology is contributing to more “aggressive” approaches in training
Eilish McColgan suggests that the shoe technology is also contributing to more “aggressive” approaches in training, racing and mentalities. “Maybe it is seeing one person break a record and thinking, ‘I can do it’,” she says. “Then another person does it and another person. It’s a bit of a mindset change.”
Any debate on human performance trends inside any sport can also hardly ignore the wider anti-doping history. In athletics, where anti-doping has been overseen by the independent Athletics Integrity Unit following the Russia scandal, there have been particular recent concerns with respect to Kenya where, since 2015, around 300 people have served or are serving anti-doping suspensions. New threats will also inevitably continue to emerge – the Telegraph reported last week of warnings inside the scientific community of a new undetectable mitochondrial transplant – but it has been encouraging to hear successful current athletes and coaches proactively speak out on the subject in recent years.
Jenny Meadows, who now coaches Hodgkinson after losing out on major medals during her own career to dopers, feared that she was leaving a sport beyond hope when she retired in 2016. She is more optimistic today. “You have to work so hard, but clean people can win and achieve things,” she says. “Seeing that has allowed me to not be as bitter as I might have become.”
Ingebrigtsen, whose stellar track record and incremental improvements can be traced all the way back to the age of eight, called for more testing last year and outlined concerns that cheats were evading detection. Ingebrigtsen has openly allowed documentary crews to film inside his life for many years and that is something Kerr has been doing increasingly in 2025.
“My goal was to show behind the scenes a bit more … knowing this sport is possible to be clean at the highest level,” said Kerr. Theirs is just one rivalry that is pushing performances forward and, with Hicham El Guerrouj’s respective 1500m and mile records still standing after more than 25 years, two of the very best in the book will surely also come under serious threat this summer.
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