After giving birth to her first child, new mom Stephanie Morrison was eager to get back into her old clothes.
Inspired by actress Jennifer Garner's strong athletic build, Morrison went in search of the workout program that turned the actress into an action hero for the movie "Electra."
"Looking like a celebrity is a little unattainable for a new mother," she told ABCNews.com. "Fitting into my clothes was my incentive. But it's always good to have something to aspire toward. And Jennifer Garner looked fantastic in 'Electra.'"
When Morrison learned that Garner's longtime trainer Valerie Waters was offering an online exercise program based on similar moves she puts Garner and her other celebrity clients through, she signed up right away.
Morrison is not alone. Since Jane Fonda donned a leotard and leg warmers in the '70s and launched the home exercise video craze, the public has been trying to emulate the fitness of its favorite celebrities.
"They are so visible and it does seem like their life is so glamorous," Waters said about celebrities. "But they are not the experts on fitness. They just tend to have a little bit more motivation because they are so visible and people talk about them."
Capitalizing on the public's fascination with celebrity fitness, Waters created Red Carpet Ready, a six-day-a-week, six-week eating and exercise plan that alternates between strength training and cardio workouts.
Using techniques she employs with Garner and other celebrity clients like model Cindy Crawford and actress Rachel Nichols, Waters offers folks at home an e-book; a weekly Web chat, in which she answers questions; and her e-mail for concerns that arise.
"I can't afford a personal trainer," said Morrison, who completed the Red Carpet Ready program. "To have Valerie Waters basically coaching me, I was able to tap into a whole new knowledge base."
Morrison said the program's sensible approach to exercise, which didn't require a gym membership, made the program doable. The exercises, which alternated between high and low intensity, were challenging but not overtaxing, she said.
And when she overextended her already weak back and had to sit out for half a week, she said Waters program gave her other exercises options, as well as encouragement to keep moving.
After six weeks, Morrison lost 10 pounds and is back in her pre-pregnancy clothes.
London-based freelance writer Ashley Pearson had a different experience, however, when she followed Madonna's grueling workout routine for five weeks and she later wrote about it in an article for Britain's Daily Mail Web site.
"It just about killed me," Pearson told ABCNews.com. "Many days I would have to fight back tears. I'd wake up and feel like I'd been in a car accident the night before."
In December, Pearson set out to learn if an "average" size-10 woman like herself could emulate Madonna's punishing workout.
The pop queen and her pal actress Gwyneth Paltrow have made headlines for their super-toned physiques, a look they honed during the last year reportedly doing two-, sometimes three-hour workouts a day with exercise guru Tracy Anderson.
To replicate the stars' routine, Pearson exercised six days a week for two hours a day with London-based trainer Jonathan Goodair, a master of Anderson's method, which includes 40 minutes of cardio coupled with 90 minutes of Pilates-based toning exercises.
For the first four weeks, Pearson, 35, literally crawled up the stairs to her apartment because walking caused her to break out into a sweat from the muscle fatigue. Every night she soaked her sore muscles in a medicinal bath before falling into bed by 10, which not surprisingly put a crimp in her dating life. In the morning she slathered herself with a smelly muscle balm and didn't care when commuters on the subway moved away from her.
But Pearson, who undertook her five-week experiment almost as a journalistic dare after Anderson claimed that her method would work for any woman of any size, discovered "it is doable," she said.
She argued that Anderson's regimen is much harder than any other, but it's also more effective. Pearson went down two dress sizes and lost 16 inches around her body in five weeks.
It's a wonder Pearson didn't get injured, Dr. Andrew Feldman told ABCNews.com.
"It doesn't take a rocket scientist to understand there's sore and then there's sore," said Feldman, the chief of sports medicine at St. Vincent's Hospital in New York. "Somebody who feels like they were run over by a train -- they are overtraining. That's not only bad for injury. It's bad for the muscles. They need recovery time. The off days are as important as the on days."
In his 15 years of practicing, Feldman has seen many people injured after trying to mimic something they see on television, video or the Internet.
"Either their bodies are not flexible or ready for it," he said. Or he'll get the "weekend warrior" types who go from working out two days a week to five and end up tearing a tendon or breaking a bone.
He said people often make the mistake of looking at celebrities and thinking, "That's something anybody could be doing, because they're just like you and me."
In reality, "someone like Madonna is not unlike a pro athlete," said Feldman, who is also the head team physician for the New York Rangers.
Celebrity trainer Kathy Kaehler agrees. "Madonna has been putting in years and years of this kind of training," she told ABCNews.com. "A friend of mine trained her in Los Angeles and those were two- and three-hour workouts. She used to run miles and miles. Someone who pops into that type of regimen is putting themselves at increased risk for injury. Their system not prepared for that."
That hasn't stopped people in the last 20 years from asking Kaehler to help them look like Jennifer Aniston, whom she has trained. When Aniston was on "Friends," she got so many requests from people who wanted arms like hers that Kaehler's mantra became "would you like me to cut her arms off and replace them with yours?" she said. "It got to be almost so silly."
Rachel Nichols, one of the stars of the ABC series "Alias," said celebrities have both an easier and a harder time staying in shape.
"A lot of times people look at someone with this amazing body and say 'I want that' and I understand. It does look easy from someone's perspective that an actor has a trainer and lots of free times that a regular person doesn't have," she said. "But the regular person doesn't have [the] scrutiny of everyone in the world judging them if go up a few pounds or have cellulite. So it's both easy and a lot of work."
Before getting the job on "Alias," Nichols, a former model, said her idea of staying in shape was "living on cigarettes and Diet Coke." Though the actress was thin, her body was soft when she began working out with Waters.
Nichols said Waters gradually changed her body, making her stronger and more toned -- "Valerie doesn't believe in working out for two hours; misery is not the way" -- and teaching her how to eat and enjoy fitness, so that she now plays tennis and does Pilates on her own.
"Regular people can do her program and change their body," said Nichols, who added nearly 15 pounds of muscle for her role in "GI Joe," before returning to her long and lean look. "It will work for everyone, without putting them through hell, without making them dread it. It's very accessible and user friendly."
New York Times cultural writer Robin Pogrebin, who got a "sampling" of a workout with Anderson, said she can see how having to do multiple repetitions of arms, leg and abdominal exercises every day could be tough. Anderson's DVDs on the other hand "a regular person can do," once the person can follow the sometimes intricate dance combos.
She gets the appeal of celebrities and their trainers. "We are a culture just craving a recipe for success," Pogrebin said. "That's why diet books sell and workout DVDs are always going to have an audience."