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

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.