SANTA MONICA  (AP) — Physical fitness is a way of life on the beautiful beachfront oasis of Santa Monica. From sunrise to sunset, there's huffing and puffing in the city's parks as trainers put their students through the paces of every form of exercise imaginable.

All along the 420 acres of greenery paralleling the Pacific Ocean are groups of a dozen or more people furiously pumping iron, doing sit-ups, stepping on and off little benches and stretching on mats. Some flex their muscles with weight machines tied by big rubber bands to pretty much anything that's anchored to the ground.

"It's starting to look like a 24-Hour Fitness gym out there," complained Johnny Gray, an assistant track coach at UCLA and former Olympic runner who says he's often forced to navigate around weight machines, barbells and other exercise impediments as he runs.

In recent years, fitness classes have become as ubiquitous in Santa Monica's signature Palisades Park as dog walkers and senior citizens playing shuffleboard.

Karen Ginsberg, the city's director of community and cultural services, said other park users are complaining about fitness enthusiasts not only blocking pedestrian walkways but also making too much noise, killing the park's grass with their weights and damaging its trees and benches with all the exercise gadgets they connect to them.

"Some people have also expressed concerns about people operating a business on city land and putting the city at risk of liability because they aren't carrying insurance," she said.

So now the City Council is considering requiring that fitness trainers who conduct workouts in Santa Monica's parks and on its beaches pay an annual $100 fee and turn over 15 percent of their gross revenues to the city.

The council was to take up the issue of regulating fitness trainers this month, but that's now been pushed back to at least March. Meantime, Ginsberg said city officials are looking at what restrictions they might put on the use of weights, bands and other equipment.

Although classes offering everything from fitness training to yoga to meditation can be found at several city parks and all over Santa Monica's beaches, Palisades Park, with its stunning ocean views, is by far the most popular place.

As a result, city officials are considering limiting exercise class sizes there to no more than two students per trainer. Under the proposal being considered, other venues could still accommodate the larger groups as long as trainers pay the fees and provide proof of insurance.

The trainers respond that, like any responsible business operators, many already are insured and also know CPR. They also point out that they currently pay the city for business licenses and police-issued permits to hold their classes in the park. Although they don't have to pay rent to anyone, they believe that's enough overhead.

"I could easily go back indoors but that's what I wanted to get away from," said Ruben Lawrence, who has been offering boxing and fitness training classes at Palisades and other parks for six years. "I wanted to provide these programs to the masses at affordable rates to the community in a place people enjoy."

Since the city began discussing the additional regulations, Lawrence said, he's moved most of his classes to other parks in Santa Monica. If he has to pay the additional fees, however, he said he'll likely just relocate to a gym.

Raisa Lilling, who offers vigorous exercise classes to the mothers of newborns, said she and other trainers have been working to keep their students quiet and out of the way of dog walkers, camera-toting tourists and others.

"I can absolutely see where they're coming from, but a complete ban, I think, is a little extreme," said Lilling, adding that the sides can always find a middle ground.

Lilling offers Stroller Strides classes in which mothers push kids in strollers across the park. As part of their workout, they'll stop from time to time for vigorous bursts of cardio activity, including running up and down the park's steep stairways to the beach while Lilling watch the kids.

"It's not just a stroll in the park," laughed the trainer, who is certified in CPR, carries insurance and also teaches yoga classes.

Ginsberg, emphasizing that planners are still fine-tuning the proposed regulations, agreed there should be a middle ground.

"I think we have to strike a balance between wanting an active community, which I think we do want, with the need to have some sort of ability for all users to enjoy our parks, particularly Palisades Park," she said.