Thousands of people are running through mud, hoisting themselves over walls and swinging over water this weekend at a 10-mile obstacle course at Old Bethpage Village Restoration.

Preservationists have blasted Nassau County for allowing the event to take place at the 209-acre county-run re-creation of a mid-19th century Long Island village that includes 51 historic buildings.

Although mud-soaked obstacles aren't next to the buildings, some of the running course comes within a few feet of several, including the Schenck house, which a county website says dates to about 1730 and is one of the country's oldest surviving Dutch farmhouses.

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Security personnel were at some historic buildings but not at others.

Event director Hilary May had previously said none of course would come within 10 yards of a historic building and that security would monitor all of them.

Natalie Naylor, president of the Nassau County Historical Society and a history professor emeritus at Hofstra University, said she plans to visit the village as soon as possible, "to see the damage."

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Tough Mudder paid the county $30,000 to use the site and agreed to restore it to its pre-event look, said Mary Studdert, a spokeswoman for the Nassau County parks department.

On Saturday, there was little sign of the controversy. Participants were focusing on swinging over a pool of water to ring a bell and running through live electrical wires hanging over muddy water.

Fernanda Borgogelli, 38, of Franklin Square, said she liked how Tough Mudder is a challenge rather than a competition. There is no award for finishing first, and teamwork is essential.

"You don't have to worry about competing with the person next to you," said Borgogelli, who also has run on competitive obstacle courses. "Instead you're helping other people finish with you."

People yelled "come on, you've got this!" as fellow participants crawled on their stomachs through mud and under barbed wire, and they extended their hands to help those struggling to make it over a 15-foot-high curved wall.

Chris Japutra, 28, of Farmingdale, who was on a team with nine friends, said he likes the camaraderie.

"The teamwork gets everyone in shape," he said. "And it definitely brings everyone together, facing challenges and facing adversity."