Backs slam against mats and rise again.
Their faces wince as people bend and twist, trying to match the pace of the non-stop, thumping music in the background.
"Up! Down!" the instructor cries. "Come on. Gotta keep those abs tight."
Moans fill the room throughout this 15 minutes of hell.
Nine students are sweating it out at the Zoo, a Fort Lauderdale Beach health club. Their goal: phenomenal abdominals.
After the class, Mark Bishop lifts his moistened shirt and with his finger draws an imaginary washboard on his stomach.
"I want to have those cuts," he says.
For a while the thighs were the body parts of the moment, then it was the butt. Now it's the abs.
Turn on your television, and you're bound to see some trim, fit guy pitching the latest product or video that guarantees a flat and taut abdomen, and America is buying it up.
The ab business has exploded. NordicTrack reports that 2.75-million abdominal machines were sold in 1995, taking a $145-million chunk of fitness industry sales, which reached $3-billion.
NordicTrack, which created its own machine, AbWorks, expects the numbers to increase this year.
"Everyone's kind of ab crazy," says Mike Smith, NordicTrack public relations manager. "The way the ab industry is heading, it will definitely exceed last year."
When QVC, the cable shopping channel, premiered its Weslo Crunch Force on June 23, 18,000 were snatched up in an hour, a QVC spokesperson says.
Machines like the Ab Roller Plus have taken over health clubs and sporting goods stores.
Eric Hursey, operations manager for a Fort Lauderdale-area Bally's, says 80 percent to 90 percent of the people who work out at the gym focus on the abdominals.
"I wish I was exaggerating," he says. "It appears that the epitome of good health is to have a nice, lean midsection."
This craze is nothing new. (Does the vibrating belt ring a bell?)
The American Council on Exercise in San Diego reports that the abdominals consistently rank among the top three body areas most exercisers would like to reduce and tone.
Strong abdominals lead to better posture and basic body mechanics, like bending over or reaching for something in the glove compartment of your car. They help support the spine, and, if they are weak, they place undue stress on the lower back.
An important point, since more than $50-billion is spent on medical care each year for the treatment of problems associated with lower back pain, according to the council.
And let's not forget the obvious. This is summertime.
"I want to have a tight, firm stomach so I can look good in a bathing suit," says Jodi Jeffreys, a student in the "phenomenal abdominals" class.
A recent surgeon general's report on physical fitness says that 60 percent of adults do not achieve the recommended amount of physical activity and 25 percent of adults are not physically active at all so, in our microwave society, people crave fast results.
"A 300-pound guy with a big beer gut will come in here and be like, "Wow, I can use this three minutes a day, and I'll get rid of my beer gut,' " says Chez Ferriero, exercise manager at the Sports Authority on Federal Highway in Fort Lauderdale. Well, that isn't going to happen.
Contrary to popular belief, spot reduction of fat is a myth.
"You can't reduce fat in one area by focusing on one area," says Mitch Sudy, vice president of programs at the American Council on Exercise. "You'll strengthen the muscle, but the fat will remain."
In other words, to get toned abs, get rid of the fat, top to bottom. That takes time _ especially when fat clings to the midsection, says Dr. Roy Alterwein, medical wellness director of the Fit for Life Health Resort and Spa in Pompano Beach.
"Fat is lost in a certain order," says Alterwein. "The last place it's going to come off is the abdominal area."
Alterwein recommends a balance of aerobic activity for the cardiovascular system, strength training for muscle toning and a low-fat diet.
The machines aren't necessarily the best option, experts say.
"Nothing beats good old-fashioned crunches," says Kelley Barnett, instructor of the "phenomenal abdominals" class at The Zoo.
Abdominal crunches and back stretches for 15 minutes at least three days a week will strengthen that midsection, Barnett says.
Eric Scallin, manager at Play-It-Again Sports, a new and used sporting goods store in Sunrise, sees the ab machines fading into the sunset like the ThighMaster.
"Everybody's always interested in buying new equipment that makes them look like a model," Scallin says. "I expect to be seeing them (returned) some time around Christmas."
Most fitness experts see no problem with that.
"People have to make a lifestyle change," Alterwein says, "not a machine change."