Double Your Fun

During partner yoga, said Farmer, "there probably would be a big mess if people didn't talk. There is just no way you can't say, 'I'm going to put my foot on your sacrum.' "

Getting It Together

Despite the obvious benefits of joined-at-the-hip fitness, there are downsides.

The cost can be formidable. While tandem bikes and boats can be had for under $1,000, the norm is generally twice that amount -- and often more than twice what comparable equipment for two singles would cost.

There are also associated expenses like special car racks to transport the craft, in addition to the usual safety equipment like helmets and life jackets.

Storing the oversized gear can present additional challenges.

The Buehlers, who like to do some tandem cycling in addition to their two-seater paddling, found the only convenient place big enough to store one of their bikes -- a 10-foot-long triple-seater -- is their living room.

"It hangs above the couch," Rick said. "It's art." •

Rita Zeidner, who used to ride a tandem bike with a friend who is blind, writes regularly for the Health section.