Katie Compton always loved playing in the mud.

As a little girl, she’d come home from an afternoon of playing with her friends, and her mother would be standing in the doorway shaking her head. Compton would be covered in filth, from the top of her head to the tips of her toes, with a smile always on her face.

“I think that’s part of why I love cyclocross,” Compton said. “It’s like you’re a kid when you’re playing in the mud, and you come home and your mom is like, ‘What the hell is wrong with you?’ And you’re like, ‘It’s fun! You should try it!”’

These days, thousands of cyclists are heeding her advice.

Popular for decades in northern European countries such as Belgium and Denmark, cyclocross has finally caught fire in the United States. The combination of road racing and mountain biking is drawing record numbers of riders to events all over the country, from elite competitors such as Compton to those just learning to pedal a bike.

“I don’t know how many riders there were when I started,” said Compton, who picked up the sport in 1999 and recently won her 10th consecutive national championship.

“I know it’s quadrupled, minimum,” she said. “Everything has gotten so big.”

If anybody could appreciate cyclocross’s explosive growth, Compton might be it. A tree-time world silver medalist, Compton will once more try to dethrone six-time champion Marianne Vos — the reigning Olympic road race champ — this weekend in Hoogerheide, Netherlands.

The discipline was born in the early 1900s as a way for European road cyclists to stay in shape during the harsh winter months, but it started to grow in popularity during the 1950s as its own sport. In the last couple of decades, high-profile European races often draw more than 20,000 fans, and television ratings rival that of the NFL in the U.S.

It hasn’t been nearly as quick to catch on in America.