Lighter than a bar of soap: The shoes Sawe wore to shatter marathon record

Assefa bettered her own world record by nine seconds on Sunday [Getty Images]

What makes the Pro Evo 3 different?

At 99 grams, the trainer is the first 'super shoe' to weigh under 100g.

That's lighter than a medium-sized apple, a banana or a bar of soap.

In recent years, major improvements in marathon times have been made thanks to the introduction of carbon-plated midsoles. The latest version also integrates carbon more fully into the design.

And in the search for marginal gains, the redesign and reduction in weight have led to an increase in running economy according to the manufacturer.

"At that level, every detail really matters – we were measuring things down to the nearest nanogram," Adidas' VP of running, Patrick Nava, said of the design process.

"It was a long process, but it's led to something we believe genuinely changes what a race-day shoe can feel like."

For the casual runner taking advantage of the technology comes at a financial cost though. A wider release is expected later in the year following on from the initial limited launch, but the shoes are currently priced at £450.

Has Adidas dethroned Nike?

When Kipchoge broke the sub-two hour mark wearing the Nike Alphaflys in 2019, the American sportswear brand was undoubtedly the market leader.

Its reputation was enhanced further in 2023, when Kiptum set the previous world record in Chicago wearing the Nike Alphafly 3s.

But just like in racing, boundaries are there to be pushed.

With Sunday's results, Adidas can now boast that the fastest man and woman to ever run a marathon both wore their shoes.

But the battle never stops between the biggest sportswear brands, particularly given the increased popularity in running in recent years.

[BBC]

What are the rules behind 'super shoes'?

Governing bodies have been trying to keep pace with advances in footwear technology over recent years and World Athletics updated its regulations in January 2022.

It released an 18-page document, which stated shoes could not be used unless they were available to "any athletes participating in applicable competitions".

The rules also stated that the maximum 'stack height' must not exceed 40mm and that the shoes must have no more than one carbon plate.

While runners can race in shoes that exceed a stack height of 40mm, athletes will not have their times recorded as the trainers are considered 'illegal'.

So, is it just the shoes?

Rapid developments in sport science in the last 20 years have run alongside the technological improvements in racing shoes.

Simply put, we know more than ever how to 'beat the wall' and to keep glycogen levels topped up throughout 26.2miles.

In Sawe's case, a research team from sports nutrition brand Maurten spent 32 days with the Kenyan across six trips in the last 12 months.

Their team, which specialise in hydrogels, worked alongside Sawe to train him to absorb the 90-120 grams of carbohydrates included in the gels within an hour period without feeling distress.

By keeping glycogen levels topped up, the body can rely on carbohydrates as its preferred form of energy, rather than fat reserves.

Almost inevitably, when landmark times are set, there are those who raise suspicions.

Ruth Chepngetich, winner of the 2024 Chicago Marathon in a world-record 2:09:56, was hit with a three-year ban for doping in 2025.

In light of his countrywoman's suspension, Sawe and Adidas asked the Athletics Integrity Unit to ramp up his anti-doping testing.

In 2025, Adidas paid $50,000 (£36,800) to increase the drug testing of Sawe in the build-up to the Berlin marathon.