Sheree Parnell arrived at the Sand Dune Park in Manhattan Beach, expecting to march up the popular 100-yard dune for what friends had told her was the ultimate cardiovascular workout.
Instead, she found the dune closed Friday and bulldozers scooping up mounds of sand.
The towering sand dune has been around since 1965, but only in the last few years have people from across Southern California flocked there for the kind of workout you can't get at a gym.
Walking or running up the dune amid the shifting sand is a cardio exercise as well as a test of agility.
It's a workout that attracts not just fitness buffs and power walkers but big-name athletes. Troy Polamalu, Andrew Bynum, Kobe Bryant and Paul Pierce have all worked out at the dune.
But some believe the dune has become too popular.
The massive wall of sand is rapidly eroding due to excessive use, officials said, and neighbors are complaining about noise, trash and parking.
"The sand has eroded. . . . It's starting to dip. A fence that prevents cars from going over is leaning and bent, and the sidewalk has been compromised," said Richard Gill, director of parks and recreation for the city of Manhattan Beach, adding that crowds have been particularly large since July 1.
Gill estimated that 6,000 people used the dune in July 2008, compared with 9,000 this July.
Councilman Richard P. Montgomery attributes the increase to the economy. He said people are cutting down on their gym memberships.
"You're not paying monthly dues," Montgomery said. "All you have to do is run up and down the dune. It's a heck of a workout and it's free."
The city closed the dune to repair damage and it's unclear when the dune will reopen.
Neighbors want it closed permanently -- or at least until the city figures out how to accommodate the growing crowds.
"I get probably 60 to 80 e-mails from those that live near the dune and e-mail me about this issue," Montgomery said.
"That doesn't count the phone calls. We're addressing it now. We're trying to figure out the best course of action," Montgomery added.
One option might be to install parking meters on some streets and impose permit parking in nearby residential areas.
The idea would be for parking revenues to help pay for maintaining the dune, which costs about $120,000 a year.
The natural dune has received a lot of attention on recreation websites and through word of mouth, with fans saying that the park is a great place for exercise.
"It's you and the dune, and it's one-on-one," Montgomery said. "It's a world-class training facility that everyone uses . . . pro athletes to the everyday athlete."
City officials said the influx of people has caused tensions with locals who are not used to the crowds.
"When you have 100 to 1,000 people, you don't notice [the trash], but when you have 9,000 come into your park though, and that same percentage is littering, you're going to notice it. . . . The numbers are up," Gill said.