No track. No motor. Among the dozens of rides and attractions at Disneyland, the one that asks the most of visitors - and their muscles - are Davy Crockett's Explorer Canoes.

It's meant to be a slow-paced, sightseeing ride around Tom Sawyer Island. But early in the morning, before Disneyland opens to the public, employees - or "cast members" as they're called - commandeer the canoes for what's anything but a leisurely ride.

The Cast Canoe Races are a little-known, friendly competition pitting 80 teams of paddlers from Disneyland, the Disney Studios and Disney Imagineering in a month-long series of races to winnow down the fastest teams to circle the Rivers of America in the park. The course is roughly a quarter-mile and takes less than five minutes to complete.

This is the 50th anniversary of the races. They got their start back in 1963 when two park employees noticed some athletic visitors on the canoes charging their way around the river. Ray Van De Warker was the foreman of the Indian war canoes ride and he challenged Jungle Cruise foreman Bob Penfield to a friendly Frontierland vs. Adventureland canoe race with teams made up of the rides' cast members.

"If you've never done it, it's hard work," said Penfield, who retired after 42 years at Disneyland. "These people that are out here racing, it's really hard work."

Five decades later, the canoe races are an annual event and other Disney theme parks have also taken them up. The Magic Kingdom at Walt Disney World has held races for 40 years; 30 years at Tokyo Disneyland; and more than 20 years for kayak races at Disneyland Paris. Hong Kong Disneyland has hosted a Dragon Boat Festival for the last five years.

At Disneyland, this year's winners of the women's division were the DC Anchor Ladies, who paddled to the finish line in 4:26:29. The coed team United made it in 4:12:67 and the men's Oarlords took just 3:57:45 to circle Tom Sawyer Island.

It's an early-morning workout for all the racers with a 5:30 a.m. start.

The Walt Disney Co. is the parent company of both the Disney parks and ABC News.