A young man in Ji’ning, Shandong Province has taken on a rather weighty task recently – becoming the fastest person to walk the longest distance in the heaviest shoes.

Cao Donghui, 21, has, according to reports, been able to traverse 10 meters in 18.4 seconds wearing a pair of 131-kilogram iron shoes. Though Cao only weighs 55 kilograms, he’s also claimed to take a few steps in shoes wearing a whopping 256 kilograms.

After Cao graduated from a martial arts school where he studied martial arts for six years since age 10, he helped his father run a farm. Cao continued his intensive strength training, attempting in particular to turn his legs into muscle machines, attaching sandbags to his ankles day in and day out for years until he felt strong enough to sport a pair of 50-kilogram stone shoes.

To add weight to his shoes, Cao found a local blacksmith who had an interesting bet – walk a step in a pair of iron shoes and Cao could have them for free. Taking up the man’s offer, Cao left him astonished as he sauntered out of the store wearing the leaden loafers.

“We eventually tried to pay him, but he refused,” Cao’s father said. “Even when Cao asked him to add weight, [the blacksmith] did it for free.”

Cao said his next step is to apply for the world record in heavy-shoe walking, currently held by Zhang Zhenghui of Hunan Province, who walked 10 meters in 26 seconds wearing 123-kilogram iron shoes in March last year.

“I’ve beat both his weight and his time,” Cao said. “Now I just have to figure out how to contact the Guinness people!”