New rides go to the extreme.(Newsroom)

You've heard of extreme sports and extreme makeovers. Now say hello to extreme waterpark rides.

Loosely defined, an extreme ride nudges people's perceptions of danger, dropping them vertically in free fall or plunging them through dark holes at fast speeds. But regardless of how the ride does it, the reaction is the same: extreme.

"It's defined by how loud the riders scream!" said Kent LeMasters, president of Southland Entertainment in Los Angeles, which owns VisionLand water and amusement park in Bessemer, Ala.

Manufacturers say what's extreme varies from person to person. Some consider the 9-foot waves generated in a wave machine awesome, while others find the family river a thrill ride.

Today, as extreme water rides take their place in the world of waterparks, manufacturers are moving toward bigger and faster thrills--and developing rides that feature high-occupancy and challenge riders' skills.

"They have to get bigger because that's how you get people to come," said one manufacturer. "Throughput is key. You get as many people as humanly possible and send them down."

For example, funnel-type rides wash several riders around and around in a bowl by centrifugal force until they drop through the bottom into an 8-foot-deep pool. Others tip the funnel on its side, oscillating riders back and forth along a slick tunnel in a free-fall sensation.