You've seen football players do the "sack dance" and the "end-zone dance." Now they're doing aerobic dance.
At the U.S. Naval Academy in Annapolis, for example, the football team learned to do the standard aerobic dance cross-steps and back-steps, all to the rhythm of Top 40s music, during the winter.
Unexpected? Perhaps. But football players aren't the only team players stepping in time to the music. And, throughout the nation, from studios and weight rooms to playing fields, fitness aficionados of all sorts are developing many new twists -- and turns -- on aerobics.
"The change I've seen is that we are incorporating a wider range of movement," says Carol Friedman, aerobics director at the Downtown Athletic Club. "Even traditional aerobics has become more sophisticated. We're bringing in some movements from classical ballet and jazz."
"Any kind of new music or movement is good," says Kathie Davis, executive director of San Diego-based IDEA: The Association of Fitness Professionals. "The reason I feel that way is that people tend to get bored, and something new lends variety to the workout."
Not that learning aerobics is easy for everyone: The first time the football players tried the grapevines and glides that are old-hat to longtime aerobicizers, they flubbed the moves.
"Oh, God, they were funny!" recalls Carol Boyer, who teaches the team "sport-specific" aerobics.
Ms. Boyer modified the usual routines, too, adding new steps to emphasize the balance, coordination, agility, bounding and quick changes of direction required by football.
"Aerobics," of course, encompasses more than dance-studio workouts. A word coined in the '60s by exercise guru Kenneth Cooper, "aerobic" exercise gets your heartbeat into the "training range." For healthy people, that means pushing your pulse up to 60 to 90 percent of what you get when you subtract your age from 220. To get a heart-helping "training effect," you have to keep it there for at least 20 minutes at a time, three times a week.
You can do that by jogging, jumping rope, walking briskly, swimming, cycling or stair climbing. In aerobic dance and exercise classes, warm-ups, stretches and body-toning exercises are packaged around pulse-raising routines done with music that hits you with an insistent rhythm of 130 to 160 beats a minute.
Those routines can be high-impact, with a lot of ballistic up-and-downs, like jumping jacks and can-can kicks. Or they can be low-impact, with bigger horizontal steps that take the exerciser horizontally across and around the room; one foot is always on the floor.
Whichever you choose, you'll find that variations abound these days:
*Sport-specific aerobics can benefit wrestlers and baseball, softball, football, basketball and tennis players, according to Ms. Boyer, who is also the local representative for IDEA. Experienced players are likely
to get the hang of it quickly.
At first, she recalls, the Navy players "didn't know the calls. They stumbled and stopped -- but still they were better than most men in the same situation. It was obvious that they were athletes; if they didn't get it the first time, they kept trying and trying."
*Aqua-aerobics is done in a pool. The water provides body-cushioning buoyancy but because of its resistance, forces you to work hard just to move your arms and legs.
*Bench, box or step aerobics keeps you stepping up and down on a low platform, bench or box. Highly demanding because you are continually lifting your body weight up onto the step, this exercise qualifies as low-impact, because you do not leap with both feet off the floor. Appearing about a year ago, step workouts are "big, big, big!" Ms. Boyer says.
*Funk aerobics is looser, more like soul dance and less like exercise than some of the other forms. The music is by performers such as Paula Abdul, Janet Jackson and M. C. Hammer. Low in impact but high in intensity, it "has really caught on," says Ms. Davis, and local instructors agree. Funk aerobics ,, appeals to aerobicizers who are "bored with the military jumping jacks" of more traditional classes, says Vanessa Stewart, who teaches it at the downtown Spa Lady. "It's more choreographed, more of a sway, more movement with the hips," she adds.
"You take jazz movements and simplify them into aerobics moves," says Brenda Miller, aerobics director at the Merritt Athletic Club in Towson. "There are power moves with the shoulders, and you throw your pelvis into it more."
*Circuit aerobics combines traditional aerobic exercise with weight training. The pounding music and the exhortations of the instructor have you lifting quickly enough to keep your pulse at its exercise-induced high. At the DAC, Ms. Friedman puts her people through their paces in a circuit-training room equipped with 17 different weight machines, where they alternate between the various presses and extensions and a stationary bike or cushioned jumping board.
You can also do circuit aerobics in a dance studio without weight machines: At the Ten Factory in Pikesville, co-owner Lynn Rosen has a class that alternates dance routines with lifting free weights.
Bench-circuit aerobics, as taught by Ms. Rosen, alternates traditional high-impact choreography with low-impact step aerobics routines.
*SALSArobics, which is gyrating out from the nation's mid-section, lets you rumba and flamenco your way through exercise dances set to the hot-tempered rhythms of the Caribbean. You can do it singly, or more sensually, a deux. Created in Chicago a few years ago, it's highly choreographed and very intense, with as much activity in the hips and shoulders as in the feet. Although Latin moves and music are also being incorporated into classes around the country, SALSArobics is a trademarked program available on video tape (Call  252-6969 for information on ordering), but taught only in Chicago, Miami and, starting this month, Los Angeles.
*Moderate or beginner aerobics is for people who hesitate to join a class in which everyone else is in great shape or already knows the moves. The music is a little slower than in regular low-impact classes, the training-range segment is shorter, and the instructors teach the fundamentals. Recently introduced at Professional Performance Institute, "Entry Level Aerobics" emphasizes technique, form and safety, according to Ms. Boyer.
"Aerobics in Moderation," at the Towson Y, is designed for people past 50, but younger people can also join the class, says Nancy Friday, associate executive director. "Everyone is encouraged to move at his own pace, and the instructor shows alternative moves: She'll say, 'If you can't do that, do this.' " Ms. Friday adds.
*Children's aerobics are aimed at the younger set. At the downtown Spa Lady, there's a Saturday morning class called "Angel Aerobics" for girls under age 8. The little ones really enjoy it, according to Deborah Teel, who comes in to work out on the weight machines and stationary bike while her daughter, Syreeta, learns to warm up and stretch and follow the instructor's rhythmic routines.