(FORTUNE Small Business) – At a meeting of the South Florida chapter of the Entrepreneurs Organization, more than 100 small-business owners are gathered in the aisles of an auditorium at Nova Southeastern University. The place is silent. Half of the entrepreneurs stand with their eyes closed and their arms stretched out from their sides, each facing a partner.

The man onstage tells the folks with their eyes shut to think "bad thoughts" as their arms are pressed down by their partners. The arms go down easily. Then the man tells them to repeat the process, this time thinking positive thoughts. No arms go down, even though some of the people pushing down have gotten on their toes to get more leverage. "Thoughts radiate physically," the man says. "Change your thoughts and you change your actions, your results, your destiny. I'm here to help you think about what you think about and to help you manage your thoughts. I'm Jim Fannin. I coach champions."

Fannin, 55, calls himself a performance coach. Since the late 1970s he has worked with more than 100 professional athletes, including rising PGA tour player Charles Howell III, Olympic gold-medal-winning decathlete Dan O'Brien, and Yankee third-baseman Alex Rodriguez. Fannin says he helps them find the optimal mental state for performance, a condition commonly known as "the zone," first popularized in the 1970s by sports psychologists. Now, adapting the proprietary system he uses with athletes, Fannin is teaching the same mindset to entrepreneurs who want to better motivate employees and build their companies.

While most of his practice still consists of athletes, Fannin is starting to do more work with businesses. He runs about 75 daylong seminars a year for trade groups, schools, and corporations such as Apple and IBM. Fannin also has signed deals with the owners of five small companies, who each pay a $30,000 annual retainer to keep him on speed-dial as a consultant. "As chairman, there's no one around to kick my ass," says Peter Haleas, chairman of Bridgeview Bank Group, which has 17 local banks in and around Chicago. Under Fannin's guidance, Haleas says, he led his bank from $250 million in assets seven years ago to $1.2 billion in 2004. "Jim and his method provide a good check-and-balance system that helps me not lose focus on what I'm supposed to be doing in the day-to-day grind," Haleas says.

Fannin isn't the only one hawking the jock-Zen mindset to bosses. W. Timothy Gallwey, whose books, The Inner Game of Tennis and The Inner Game of Golf, helped explain the importance of mental visualization and relaxation to weekend athletes, published a business version in 1999 called The Inner Game of Work. It has appeared on reading lists at business schools such as San Francisco State University's. By contrast Fannin still spends most of his time working one-on-one with clients. (He claims to go through more than 6,000 cellphone minutes a month.) He has a book and infomercial due out early next year to introduce his techniques to small-business owners who can't work with him individually. All of which raises the question: Does this stuff work?

Fannin's consulting career can be traced to a day in 1971 when he was a country-club tennis pro in Columbus and lost a match he had been winning. He started analyzing why. "It was one of my first recollections of 'the zone' and how you can lose it instantly," he recalls. "By the time I got up off the locker room bench, I made up my mind to find out what exactly that mindset was and how to make it stick."

Over the next few years Fannin developed Tennis Tots, his noncombative, six-week program for teaching the sport to toddlers. Based on research he commissioned from three motor-skills-development professors at Ohio State University, Fannin hypothesized that a child's attitude and mental state--not athletic ability--were a better indicator of how he would do on the court. Fannin's curriculum used repetitive drills to teach kids attitude traits that he gathered after interviewing tennis greats including Bjorn Borg, Jimmy Connors, and Chris Everett. The most important, he found, were self-discipline, concentration, optimism, relaxation, and enjoyment. Fannin packaged them all into a marketable acronym: SCORE.

The program worked with kids and, he soon found, pro tennis players as well. (Fannin has coached, among others, the 1979 Italian Davis Cup team and Peter Fleming, who partnered with John McEnroe to become the No. 1 doubles team in the world during the 1980s.) In late 1979, after three Tots graduates had become national junior champions, the Chicago Indoor Tennis Association bought the program for $5,000 and moved Fannin to Chicago to run it. There he met Dr. David Orth, parent of a Tennis Tot and a minority owner of the White Sox. "He said he had a catcher who kept choking when he got up to bat," says Fannin. "Could I somehow use SCORE to help improve his game?" Fannin visited the player, Ron Karkovice, in the Sox dugout before games, asking him to try a new preparation routine before each at-bat: Take practice swings for low-ball pitches while on deck, observe the pitcher's body language to help anticipate the pitch, and loosen his jaw. "My problem was tensing up, then this tendency to pull up and off the ball," says Karkovice, 41, who adds that his on-base percentage and number of walks spiked after sessions with Fannin. "Opening up my mouth seemed to relax my whole body." Karkovice, who retired from baseball in 1998 and owns a restaurant in Orlando, worked with Fannin for three years, becoming his first well-known client outside the tennis world.

Whether his client is an athlete, an entrepreneur, or an entire workforce, Fannin's prescriptions are fairly similar: visualization, relaxation, and positive thoughts. After meeting with a CEO to discuss the company's overall goals, Fannin sets up a group meeting with the employees considered to be the company's weakest links and explains the way that thoughts--both positive and negative--manifest themselves in actions.

George Collins, 64, general manager of a Toyota dealership based in Hialeah, Fla., asked Fannin to work with his salesmen in 1999. His company had reached a plateau in its growth, and Collins, who had heard about Fannin through another dealer, was hoping the consultant could help get sales climbing again.

Fannin described to Collins's 22 sales managers how top PGA touring pros such as Charles Howell III use visualization techniques to "illuminate the pathway from their goal--the green--back to where they are." Fannin also met with the salesmen individually, asking each to draw circles around the most important areas in his life--family, friends, work--and highlight the people and thoughts within it. Negative thoughts, such as worrying about work while at home, were crossed out with a red marker. The managers listed specific tasks they could perform daily and weekly to reach the goals in each area of their lives.

It doesn't sound like radical stuff, yet the dealership's revenues have tripled in the five years since Fannin first visited. Collins, who retired in June as the dealership's manager but serves as a consultant, specifically credits Fannin with the spike in his sales teams' commission-based pay--up $100,000 from last year alone. "If we knew a guy was down in the dumps or getting a bad attitude, we'd have Jim call him," says Collins, who speaks to Fannin twice daily. (To an outsider, their phone conversations sound almost like gossip sessions.) As with all five of his small-business clients, Fannin flies in once a month to meet with the staff individually and in groups.

Fannin's techniques work best in environments that are similar to sports, particularly when compensation is based on performance. "The psychology of stock trading is much like sports--I needed to be more consistent," says Travis Vincent, 32, a financial-futures trader in Chicago who signed on with Fannin last summer. "Once we went over what I wanted to accomplish, we'd talk every day," Vincent says. "He would help me determine why I lost money that day, boiling it down to the specific trade that went wrong--was I thinking negative thoughts at that specific moment?"

Fannin asked Vincent to visualize his workday right before falling asleep the night before, and immediately after waking. He told Vincent that he should set daily goals, and not let the previous day's failures bleed over into the current day's performance. Within two weeks Vincent noticed that he was detaching himself more quickly from bad trades. Within a month he doubled his income, and after another month he realized that he wanted to quit his employer and start his own company. Vincent launched Green Light Trading with three partners in February. The firm, which buys and sells futures on European equity indexes, has eight traders on staff, to whom Vincent is teaching Fannin's techniques.

That's an approach that Fannin says he encourages among his clients, athletes as well as entrepreneurs, who should not require constant involvement from him once they've learned his methods. "The system is more powerful than I am," he says. "I'm just the messenger."