If you belong to a gym and have fallen off the fitness wagon, maybe a trip to the park or beach is in order. Not to lie on your back, but to get moving again. So says Dr. Rhonda Fine, a Miami psychologist who advises health nuts and the people who train them on how to get their mojo back.

Fine's advice to people who've gotten out of the fitness routine? Find an open-aired, attractive place to exercise.

"We tend to perk up in the sun," says Fine, who is sometimes a consultant to fitness trainers. "On the scientific side, it has been proven that the sun generates endorphins in our bodies that give us energy, give a boost. And so in times of depression and worry, if we can't continue a routine, the best thing is to try that routine in a cheerier location."

Fine says the economy's also to blame. "So many people are depressed or worried about the state of the economy that they find themselves almost paralyzed with fear and unable to do all but the most necessary things for survival. Personal fitness, at times like these, is often one of those casualties. You just don't feel like working out."

Chauncey and Pauline Williams have been training clients in all sorts of locations for more than 10 years, through their Body Preference Total Fitness & Personal Training Center in North Miami Beach, Fla.

"We've had 'em running stairwells, working out in a traditional gym setting, outdoors in wooded park areas, everywhere you can think," Chauncey says.

Lately that's included more outings to the beach. "When we take 'em to the beach it's to get 'em outside and in a bright, upbeat place, because we know that could be the trick to really get them feeling positive again."

Taking Fine's advice, on a recent Saturday morning, fitness trainer Marquel Wimbley led a small group through exercises on the sands of South Beach in a class she organized for the nearby Z Ocean Hotel.

Vance Sams says the beach boot camp is the thing that got him back on the fitness wagon.

"It's tough times right now,' said Sams, 43, who juggles three jobs — personal security work, private investigating and property management for wealthy snowbirds. "Because of two out of my three jobs, I have to stay fit. But for a little while I just wasn't motivated to go to the gym. Being inside the gym is same old, same old."

Heather Murphy, who works in real estate sales, has every reason to be depressed, given the downward turn of the real estate industry. She also joined Wimbley for the beach boot camp to shake things up.

"It's sort of like one of those things you do every so often to throw off your routine and keep yourself on your toes. Except in the past I've done that as a way to simply alter my workouts. Now? I'm doing it because I don't want to work out, period."

Marquel led the group through 90 minutes of sprints, push-ups and calisthenics, with some yoga for a cool down.

"I like to think of this as a kickoff to get back into exercise," Wimbley said. "It's mental. You workout. You get endorphins. And you feel good. It covers everything … being on the beach — especially a beach in the Miami area, and having the sun above your head? That should be enough motivation for anyone."