As the American waistline continues its spread, fitness is shaping up as one of the hottest careers of this tepid economic recovery.

Employment of fitness trainers and instructors is expected to grow by a brisk 24 percent in the decade to 2020, according to the U.S. Bureau of Labor Statistics, as businesses, health professionals and insurance companies take sharper aim at the sedentary lifestyle.

"The obesity epidemic has produced a lot of noise and talk and chatter," said Cedric Bryant, chief science officer of the American Council on Exercise (ACE), which has certified more than 50,000 fitness professionals.

"Helping individuals be more active is important and fitness professionals can be at the center of that," he said.

Obesity rates have sky-rocketed in the last 20 years. More than one third of adults in the United States are obese, according to the U.S. Centers for Disease Control and Prevention.

Bryant said the health crisis is strongly linked to the lifestyle choices that fitness professionals, such as personal trainers and group fitness instructors, address.

Despite the shaky economy, health club membership is up more than 10 percent over the past three years, according to IHRSA, the International Health, Racquet & Sportsclub Association.

Exercise physiologist and ACE spokesperson Jessica Matthews said workplace wellness campaigns also increase demand for fitness professionals.

Bryan said the average salary for a certified personal trainer is about $53,000 and rising. A high school diploma is sufficient to begin a career in fitness, he added, although more than two-thirds of professionals have college degrees.

Matthews said the industry attracts career changers driven by the downturn to reinvent their working selves.

"In the last few years people have been coming from all different industries," said Matthews, who has worked in fitness for 12 years.

While you don't need college to enter the field, she said, continuing education is a must to remain in it.

"It's accessible, but it involves a great commitment," she explained. "There's the preparation and study for the exam, and then the requirement of continuing education to stay current."

Bryant said the individual must re-certify every two years.

Matthews, who is qualified in group fitness, personal training and yoga, said the most successful trainers are the constant learners.

The obesity epidemic is the United States is also a contributing factor.

"There's a huge push from the weight standpoint," she said. "Most people come to fitness professionals with weight goals."

Bryant said the profession is about more than aesthetics: it's about making a connection with the client.

"It's called personal training for a reason," Matthews explained. "You're an educator, a motivator, someone who holds them (clients) accountable. You coach individuals. At the end of the day it's customer service."

Husband-and-wife team Phil and Michelle Dozoirs opened their mom-and-pop gym, BreakthruFitness, in Pasadena, California, just as the economy was tipping into free fall.

"We opened in 2009, pretty much when the economy fell apart, said Phil Dozoirs. "We had both been working in gyms for 15 years, me as trainer, my wife as group exercise instructor."

The Dozoirs envisioned and created a club where people buy only what they need.

Dozoirs said his programs range from eight-week weight loss to total conditioning.

"People will pay more money for it if there's a start-finish," he said. "For us it's been really successful financially."

When he hires a new fitness professional, Dozoirs said he looks for a person with a pleasing personality who is open to learning.

"They don't have to be fit, as long as they're on the path to fitness. I believe they should walk the walk," he said.