Silhouetted against a stark brick wall, a speed bag bobbing inches from her face, a young woman says, "I promise I will work so hard."

"And you are not going to come crying to me when you get hurt," an older man responds.

It's Hilary Swank and Clint Eastwood, playing a scene in "Million Dollar Baby," filmed this summer in Los Angeles. Eastwood directed the drama and plays a disillusioned trainer who finds new heart teaching a woman to become a professional boxer.

But the dialogue could just as easily reflect an off-screen conversation between actor and director. Savvy from watching myriad close-ups and slow-mo replays during televised sports events, today's audiences expect more authenticity from actors who portray athletes. And as several new and upcoming movies demonstrate, actors are going the extra mile to attain the physique and form of professional sportsfolk.

Eastwood's credentials are certainly in order. The 74-year-old filmmaker, who says he "boxed a bit when I was a little kid," later trained with Al Silvani, who worked with pro fighters including Rocky Graziano. Silvani, now deceased, also provided technical help on Eastwood's 1978 film "Every Which Way but Loose" as well as "Raging Bull," which won Robert De Niro an Oscar in 1981.

Eastwood says he doesn't believe moviegoers will accept body doubles, trick edits or computer-generated special effects in a realistic emotional drama. For "Million Dollar Baby," which will reach theaters later this year or early next, it was important for his leading lady to have the right stuff.

"I liked Hilary as an actress, and after I met with her I felt she had the work ethic," says Eastwood. People who work on Eastwood sets aren't given to hyperbole, so no one is suggesting that Swank could turn pro tomorrow. But technical adviser Don Familton of the La Brea Boxing Gym praises "her energy, attitude, enthusiasm and aptitude."

Swank was the ultra-slender winner of the Best Actress Academy Award in 2000 for "Boys Don't Cry." Dressed in a gray T-shirt and jogging pants, her hands wrapped in punching bandages, her hair an untidy braid, her only makeup sweat, the actress says: "One of my big passions as an actor is embodying the character . . . so I just knew in order for this to really work, I really had to pass as a boxer."

Swank adds, "I knew I needed to gain weight, but it had to be muscle." So she trained for three months before filming -- 2 1/2 hours a day in boxing classes with an additional 90 minutes lifting heavy weights. She upped her protein intake, drank egg whites and flax oil, ate raw fish and woke up in the middle of the night for a protein shake. Her left rotator cuff gave her some trouble for a while, and she developed infected blisters from being on the balls of her feet when she sparred.

But she ended up with the muscle and the moves, able to land a punch and take one in the gut. No doubling needed.

It's doubtful that Katharine Hepburn did anything so rigorous when she played top athlete Pat Pemberton in "Pat and Mike."

In 1952, professional sports on television weren't ubiquitous -- nor was television itself -- so, except for snippets in movie newsreels, it's unlikely that many in the audience for that romantic comedy co-starring Spencer Tracy had ever seen a tennis or golf tournament. Jack Kramer, the 1947 Wimbledon and U.S Open tennis champion, arranged for Hepburn to appear opposite stars of his pro tour circuit including "Gorgeous" Gussie Moran and Frankie Parker. He says he "enjoyed the picture," but he's too honest not to respond with anything but no when asked if Hepburn looked convincing as a top-ranked tennis and golf star.

"Luckily for Miss Hepburn, she had a court at her house and she played a lot," he recalls. "She didn't play well. She could get the ball in, but her strokes would have never let her play in any ladies' events. It was the same with her golf swing. I imagine the director had to do a lot of editing to make it look good even for the fans out there who mightn't really know the difference."

Actors who follow the most grueling training regimens to portray athletes can still end up feeling a bit sheepish when they realize what they're up against. "It was a real arrogant, stupid decision, I think, born out of complete ignorance," jokes Paul Bettany, who, despite never having played tennis, took the role of Peter Colt, who falls in love with fellow player Lizzie Bradbury (Kirsten Dunst) in the just-released "Wimbledon."

Helped by, among others, 1987 Wimbledon champion Pat Cash, Bettany trained for six months. The British star thought it would be "lovely" to do a romantic comedy and spend some time in London with his family, but "six months of tennis training and weightlifting hove into view."

He adds: "I was feeling quite good about myself. Then I see people like Roger Federer play. It was slightly upsetting, I can assure you, because all the scales fell from my eyes, and I realized basically what I had said I could do was tantamount to saying, 'I'd love to play Rudolph Nureyev. How long do I have to learn ballet?' "

Some filming took place last year at the title location, the All England Lawn Tennis and Croquet Club, but many action scenes on Center Court were re-created on a soundstage, where grass was laid over concrete. Diving for the ball was "bone-shaking," says Bettany, who fractured a rib and tore up a leg. Nevertheless, with the velocity and accuracy of Colt's game aided by computer graphics, Bettany says he is "pleasantly surprised with the result." Whatever the role, he says, an actor can go only so far toward authenticity. "No one expected me to become a psychopath when I tried to represent one on-screen," he says.

Down the years, numerous stars have tried to portray jocks, with mixed results. Kevin Costner seemed to pass muster as a minor-league catcher in "Bull Durham" and a golf pro in "Tin Cup." Burt Reynolds, a former college player, clearly knew what he was doing on the football field in "The Longest Yard." Robert Ryan's "The Set-Up" is considered a fine boxing film. But there were also Anthony Perkins, curiously cast as the emotionally troubled baseball player Jimmy Piersall in "Fear Strikes Out," and William Bendix, who -- despite having been a Yankee batboy -- wasn't able to convince anyone he was his hero in "The Babe Ruth Story."

The comedian Bernie Mac doesn't have to look as impressive as Ruth in "Mr. 3000." He plays a clearly over-the-hill major leaguer determined to set a batting record. As the Buena Vista comedy's promo line suggests, he's "Back in the game. Out of his league." Technical adviser Rob Miller, from a company called Reel Sports, says Mac did well after help developing the "stance, hand position, swing and the presence a major-league player would have at the plate, so he would be comfortable facing live pitching."

"Actors will say they can do pretty much anything if they want to get a part," laughs Peter Berg, director of "Friday Night Lights," which opens Oct. 8 and is based on H.G. Bissinger's book about high school football in Texas. Some of the young actors Berg hired "said they knew more about football than they really did, and I caught them reading 'Football for Dummies' in the hotel lobby."

Aware that television coverage has "provided audiences with a certain level of expectation about how they want their sports to look," Berg hired NFL cameramen and didn't use computerized special effects except to fill in crowd scenes in the stands. But he did use doubles, something easier to do because of the camouflage of football gear. "It's a rough sport," he explains. "You don't want to hurt your actors, so we brought in a bunch of college players to do the heavy hitting."

Penny Marshall, executive producer of the basketball documentary "Crossover," couldn't use doubles in 1992 when she directed "A League of Their Own," about the women's professional baseball circuit of the 1940s. The skimpy outfits would have made it hard to disguise impostors.

"I wouldn't read [audition] an actress unless she passed the baseball test," says Marshall, "hitting, catching, fielding, running and throwing -- that's the hardest." Actresses deemed adequate included Geena Davis, Rosie O'Donnell, Tea Leoni and Madonna. They literally had to throw themselves into their roles. There were broken fingers and twisted ankles. "They played hurt, like the real ladies of the league had played hurt," Marshall says.

"The first thing you are looking for when you are teaching actors or actresses sports is what kind of athleticism they have," says Dane Selznick, coach of the Olympic gold-medal-winning beach volleyball duo Misty May and Kerri Walsh. He had a very different assignment earlier this year. He was technical adviser on "Cloud Nine," a comedy slated for release next year about a bunch of strippers corralled into forming a volleyball team. Although pro volleyballer Gabrielle Reece is in the cast, most of the actors had no prior knowledge of the sport.

"It was a pretty big task to try to teach some basic skills within a week and a half," says Selznick, who points out that the ball can travel at 70 mph.

A baseball is harder and travels even faster. The pilot episode of the new CBS drama "Clubhouse" was shot at Dodger Stadium and directed by Gavin O'Connor, who made "Miracle," a re-creation of the U.S. Olympic hockey team's famous 1980 win over the Soviets. But subsequent episodes use a small local park, a home plate constructed on a soundstage with "green screen" backdrop to allow special effects, and directors not necessarily knowledgeable about sports.

Technical advisers Rick Smith and Steve Savage are happy that at least the lead actor, Dean Cain, playing a multimillionaire major-leaguer in the drama about the life of a batboy, is an athlete who trained with ReelSports and knows what he's doing at the plate. Cain, a football star at Princeton before he became Superman in the 1990s series "Lois & Clark," says, "The producers took me on faith that I could swing a bat."

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