Tigist Assefa (left) was a track runner before she took up marathons in 2022 (Credit: G.Garitan/ CC_BY-SA 3.0/ Wikimedia Commons)

On September 23, 2023, 26-year-old Tigist Assefa shattered the Women's Marathon World Record in Berlin, Germany. The Ethiopian runner completed the 26.2-mile race (42 km) in 2hrs 11min 53 seconds — 2min 11sec faster than the previous record set by Brigid Kosgei in 2019. The achievement is even more impressive when considering that Assefa began her career running short distances on track. She only started running marathons in 2022.

"I knew I wanted to go for the world record, but I never thought I would do this time. It was the result of hard work," Assefa said.

The Adizero Adios Pro Evo 1 is the lightest running shoe ever made (Credit: Adidas/ CC-BY-SA-2.0)

The remarkable achievement is primarily due to the hours of training the athlete put in to compete and race at this level. But Assefa also had some help from a cutting-edge racing shoe from Adidas that she kissed after crossing the finish line.

The Adizero Adios Pro Evo 1 is labeled as "a running shoe like no other." Weighing a mere 0.3 lbs (138 grams), it is one of the lightest racing shoes ever created. For comparison, the average lightweight racing shoe weighs about 0,75 lbs (340 grams). It is also 40 percent lighter than any other Adidas racing super shoe.

Tigist Assefa wearing the lightweight shoes at the Berlin Marathon (Credit: IgorCalzone/ CC-BY-SA-4.0/ Wikimedia Commons)

The minimal weight is achieved with the help of a lighter foam in the midsole and no sock liner. The shoe's upper part, made with a translucent mesh, also helps. However, the most significant weight saving (0.15 lbs) came from a new, revolutionary outsole.

"It's the thinnest and lightest outsole we've ever created," Adidas' senior global product manager Charlotte Heidmann told Runner's World. "It's still [made of] rubber, but it's completely flat — there are no grooves anymore. But the grip is still the same."

Adidas maintains that the shoe's low weight improves the athlete's running economy. The term refers to the amount of oxygen the body uses to keep a certain pace. It also reduces the runner's energy usage, making the athlete more efficient.

The "super shoes," released in limited quantities thus far, cost an eye-popping $500. The high cost is even more astounding given that they are single-use shoes — built to last for just one race, plus some training time!

Not surprisingly, the design flaw and high price have drawn some criticism. Environmentalists are concerned about the waste the shoes will generate. Sports experts worry that the steep cost could be a disadvantage for runners unable to afford the shoe.

"Athletes have qualified because they had access to a super shoe," said Professor Yannis Pitsiladis, who sits on the International Olympic Committee. "And many who were not running in these shoes didn't qualify."

Regardless of the controversy, Assefa is a fan. "This is the lightest racing shoe I have ever worn, and the feeling of running in them is an incredible experience," she said.

Resources: NBCnews.com, abc.met.au, theguardian.com, msn.com