Over and over, cyclists cascaded down the drop, their skinny bodies shaking violently as they slowed for a 90-degree turn around a small tree that whacked almost every one of them in the face on the way past.

A searing blue sky belied temperatures in the 30s last weekend as the riders huffed onward through a tight coil of hairpin turns and muddy track, climbing and dropping again around a course at times too steep to pedal, and in places too log-strewn to ride.

“It’s the hardest thing I’ve done on a bike,” said Dwight Waters after competing in his first cyclocross event at the Terra X race in the Woodlands’ Terramont Park.

What he’d completed — cheered on by his bundled-up family on the sidelines — was essentially a 30-to-45-minute-long sprint. All the riders in each class start at the same time, pedaling like hell until an official announces the last lap, when each vies even harder to be at the front of the pack.

Legend has it that the sport started in Europe at the turn of the last century as a way to keep road racers in shape during the winter months. Courses led competitors through pastures and over obstacles that forced them to dismount as a way to keep their toes from freezing. These days the bikes are nicer – some riders even use all-out mountain bikes – but the races are as grueling as ever.

“It’s basically looking to get a variety of terrain,” race organizer Craig Fitzgerald tells me. A course should be challenging and diverse, but not impossible. Last weekend’s track was a 1.33-mile loop through a grassy park and section of woods, with at least one part that required riders to carry their bikes.

The races last from 30 minutes to an hour, depending on the category racing. Riders come in a diverse range of sizes, ages and genders, although they all seem to be in pretty good shape.

“Cyclocross will give you a lot more full-body workout than a road bike,” Fitzgerald says.

To give it a try, the Gulf Coast Cycling Association, Yetti Cross or the Texas Bicycle Racing Association are good resources for events in Houston. Local races usually kick off in September or October and continue into the winter with a break around Christmas. Cyclocross riders tend to be a motley bunch, with shaggy young guys riding mountain bikes beside lithe roadies who look like they ought to be making their way across France.

Waters says the cyclocross crowd tends to be friendly and even a little more easy-going than the racers at road events. The Cypress businessman took up road biking after a long hiatus from cycling and recently added the challenging bike-handling skills and endurance of cyclocross to his riding repertoire.

“It was excruciatingly painful, but I’d do it again,” he says.