Now that Hellen Obiri and Sisay Lemma have etched their names in the Boston Marathon history books, there’s one outstanding question everyone wants answered: What were the fastest shoes in the 2024 Boston Marathon?

Obiri won her second consecutive Boston title wearing a pair of On prototype shoes called the Cloudboom Strike LS Dev 1.2. It’s a shoe that’s been vetted and approved by World Athletics, but On isn’t saying much about it except that it’s keeping it top secret for now. It seems to be a maximally cushioned shoe which presumably has some sort of supercritical midsole foam and a carbon fiber propulsion plate. But the most striking feature is what appears to be a stretchy knit laceless upper.

Obiri won both the Boston Marathon and the New York City Marathon in 2023 wearing a pair of prototype shoes On has called the CloudTri 1. But that shoe, which was also approved by World Athletics, hasn’t yet become commercially available.

While that was certainly the most intriguing shoe of the race, the most prolific was the Adidas Adizero Adios Pro Evo 1. The ultra-light carbon-plated white and black racing shoe was worn by men’s champion Sisay Lemma (2:06:17), as well as fifth-place finisher Albert Korir (2:07:47) and women’s fourth-place finisher Buze Diriba (2:24:04).

In all, three of the top nine men wore that shoe, as well as six of the top 20 women. Somewhat surprisingly, two-time defending Boston Marathon champion Evans Chebet didn’t wear the shoe, instead opting for a pair of Adidas Adizero Adios Pro 3 that helped him win the race in 2022 and 2023, as well as the 2022 New York City Marathon.