May 1, 2000 (Reno, Nev.) -- Every few years, a new class takes the fitness world by storm. In the late eighties Jane Fonda and her ponytail-bobbing, leg-warmer-wearing aerobics classes were all the rage. In the early nineties, the step bench was introduced and heart-pounding step aerobics quickly became the yardstick by which all other sweat-and-spandex endeavors were measured. Now there's cardio-kickboxing, offered by nearly 80% of health clubs nationwide.
Sometimes called boxing aerobics or just plain kickboxing, cardio-kickboxing is a hybrid of boxing, martial arts, and aerobic dance that offers a high-intensity, aggression-releasing workout without the mind-numbing boredom that can come with some other gym-bound activities. But even this fad comes with a drawback: While its popularity continues to rise, so do reports of injuries. With cardio-kickboxing, it's especially wise to get some basic training info before you start throwing punches.
Why the Kickboxing Craze?
According to a recent study by the American Council on Exercise (ACE), cardio-kickboxing participants can expect to burn an average of 350 to 450 calories per hour and maintain a heart rate at 75% to 85% of maximum, well within the recommended 65% to 85% range for aerobic exercise. An hour-long session is roughly equivalent to an hour of brisk walking or light jogging. But cardio-kickboxing has a distinct advantage -- it's a truly versatile, cross-training workout. Neither of the pedestrian activities improves strength, flexibility, coordination, and reflexes the way cardio-kickboxing does.
"You burn tons of calories and get into terrific aerobic shape without having to run miles and miles," says Dan Hamner, MD, a sports medicine and rehabilitation specialist who works with competitive fighters and martial artists in New York City.
Unlike the incessant step-kick-repeat combinations you're likely to master in step aerobics class, the moves in cardio-kickboxing actually can have some real-life application. As you punch, jab, and protect your face from an (imagined) attacker, you're learning to protect yourself, only without the bruises. By practicing some simple self-defense moves in a fun atmosphere, many people -- women especially -- gain a greater sense of empowerment and self-confidence.
But you needn't have the desire to smack someone to participate. The only punches you'll throw in most cardio-kickboxing classes are into the air while you jog in place or shuffle from side to side; some classes provide punching bags, but this is the exception, not the rule.
Don't Let an Injury Put You on the Ropes
If step aerobics can be hell on your knees, careless cardio-kickboxing fans may wind up with other creaky parts. In fact, with kickboxing, there's a fairly significant risk of injury. Participants throw punches with such gusto that their elbows, shoulders, knees, and lower backs often pay the price. Extensor tendonitis (commonly called "tennis elbow"), overuse injuries of the knee, and strained groin and back muscles top the list of injuries, says Hamner, who's also a spokesperson for the American College of Sports Medicine.
So how can you protect yourself? Three words: Ease into it, says Hamner. In fact, before you even throw a punch, take a moment to introduce yourself to the instructor, so that he or she knows you're new. Many gyms don't offer beginner classes, and some instructors teach to the most advanced student in the studio. Ask the instructor to show different levels of various moves. (To ensure that you're learning from someone who's qualified to guide you, ask your instructor about his training and certification. Fitness organizations such as the American Council on Exercise (ACE), and the American College of Sports Medicine (ACSM) offer certification courses.)
Once the music kicks in, you shouldn't immediately start kicking too. Every cardio-kickboxing class should begin with a light cardiovascular warm-up and stretches that focus on the shoulders, back, legs, and groin before moving into punches, hand-strikes, and kicks. After the warm-up, you should focus on repetitions of simple moves so that you can refine your form and technique before moving into combinations that require you to use several muscle groups at once. Every workout should end with a cool-down that lasts at least five minutes.
During your first few sessions, don't go overboard. Ignore other people who seem to be killing themselves. You should work at a moderate pace, say, 65% of your maximum heart rate. Even if you're in decent aerobic condition and strength-train consistently, start slowly. The various moves in a cardio-kickboxing class are still unfamiliar to your body. Needless to say, don't hold dumbbells, wear ankle or wrist weights, or punch or kick bags until you're confident that you've learned proper form. These kinds of weights and bags, combined with incorrect form, can increase your risk of joint injury.
Finally, think like a dancer or gymnast; that is, keep a watchful, perfectionist eye on your form. Don't lock or over-extend your knees or elbows when throwing punches or kicks. In fact, beginners should do half-kicks until they know the routine and are confident that they're flexible enough to do the moves to full extension. When your form gets sloppy, the risk of injury increases, so stop when you feel tired.
Dana Sullivan is a freelance writer in Reno, Nev.