What is cardio-kickboxing?
How many calories does cardio-kickboxing burn?
Advantages
Disadvantages
Who should participate?
What to look for in a cardio-kickboxing class
Exercise guidelines
Cardio-kickboxing gear
Glossary of terms

Bored with your aerobics class? Looking for a high-intensity workout that will increase your strength and flexibility while burning fat? Are you reasonably fit already? Then cardio-kickboxing may be for you.

Cardio-kickboxing invaded the nation's health clubs with startling speed. According to a 1998 member survey by the International Health, Racquet and Sportsclub Association (IHRSA), a nonprofit trade group, 78 percent of 2,913 health and fitness clubs in the United States offered cardio-kickboxing classes. A few years earlier, cardio-kickboxing barely existed. "Many trends in the fitness industry gradually take hold, whereas kickboxing really came in and just blew everyone away," says IHRSA spokesperson Maeve McCaffrey. "I'd say you'd be pretty hard-pressed to go into any urban club and not see a couple of classes on the schedule."

What is cardio-kickboxing?

Popularized by Billy Blanks' 1998 Tae-Bo video workout and infomercials, cardio-kickboxing (a.k.a. aerobic boxing, Aerobox, Boxercise, Boxaerobics and others) is a high-impact cardiovascular workout that blends elements of boxing, martial arts and traditional aerobics into a 30- to 60-minute exercise routine.

Classes vary but generally feature a variety of punches, kicks, knee strikes and other self-defense moves interspersed with a bouncing "base" move.

Some cardio-kickboxing classes spend at least part of the time kicking and punching weighted, padded targets or engaging in actual sparring. The class may also incorporate traditional exercises, such as jumping jacks, abdominal crunches, leg lifts and push-ups to create a total body workout.

How many calories does cardio-kickboxing burn?

According to a study by the American Council on Exercise (ACE), cardio-kickboxing burns an average of 350 to 450 calories per hour. The caloric expenditure during a typical cardio-kickboxing class is roughly equivalent to an hour of brisk walking or light jogging for the average person.

Advantages

In addition to improving and maintaining cardiovascular fitness, cardio-kickboxing increases strength and flexibility, improves coordination and balance, and sharpens reflexes, according to ACE. Cardio-kickboxing also relieves stress (imagining your boss' face on the target), and it can be done at home in a relatively small space.

Disadvantages

Even if you are physically fit, cardio-kickboxing poses considerable risk of joint injury, particularly for beginners and those who use incorrect form.

According to ACE, the most common, potentially injurious cardio-kickboxing mistakes are:

• Overextending kicks
• Locking your joints when throwing punches or kicking
• Exercising beyond fatigue
• Wearing weights or holding dumbbells when throwing punches

In addition to using correct form, it is important to work out at your own pace; don't feel pressured to punch as fast or kick as high as the rest of the class. Only advanced students should be kicking above waist level. Your speed, endurance and flexibility will increase with practice.

Who should participate?

Cardio-kickboxing is ideal for physically fit people who exercise aerobically at least three times a week. The activity can be adapted for people who are less physically fit. Cardio-kickboxing should be approached with caution if you have balance problems or certain other medical conditions, especially joint disease affecting the knee, hip, ankle or back, says Richard Cotton, chief exercise physiologist at ACE. Before enrolling in a cardio-kickboxing class or any new exercise program for that matter, discuss your plan with your doctor and obtain medical clearance.

What to look for in a cardio-kickboxing class

If possible, observe or participate in a class on a tryout basis before committing any money. Look for an instructor who keeps a close eye on the class and modifies routines for varying fitness levels, says Richard Cotton, chief exercise physiologist at ACE. Every class should include warm-up and cool-down phases as well as time to stretch warmed muscles. The class should not be overcrowded.

The instructor should have a group exercise certification by a nationally recognized organization, such as ACE or the American College Of Sports Medicine. While these certifications are not kickboxing-specific, they do indicate that the instructor receives continuing education and has passed an exam demonstrating, among other things, knowledge of body mechanics, exercise physiology and group leadership. Ask where the instructors were trained to teach cardio-kickboxing and how much experience they have. Solicit opinions from other participants whose fitness level appears similar to your own.

Exercise guidelines

In most aerobics classes, you watch yourself in the mirror most of the time. While cardio-kickboxing, you generally train your eyes on the target you are punching or kicking, be it real or imagined. This means, for example, turning your head and watching your foot when you are making a sidekick.

IDEA, an international organization for health and fitness professionals, offers the following suggestions for exercisers seeking a safe and effective cardio-kickboxing program:

• Look for a simple program that isn't heavily choreographed, has limited repetition and isn't too fast.
• Start working out once a week and gradually build up to no more than three sessions weekly unless you are also doing some other form of martial arts or sport-specific training.
• Progress slowly, and keep kicks low. Do not over extend kicks or lock your joints. Avoid throwing full kicks and punches in the first class.
• Find a program that alternates high-intensity bouts with recovery periods that offer slower moves. This reduces your chances of getting fatigued and sacrificing good form.
• Your warm-up should be specific to the class and should include static and dynamic stretching, with some kicks and light punches.
• Consider complementing your cardio-kickboxing program with non-impact, more linear forms of exercise such as indoor stationary cycling, walking or hiking.
• Try traditional martial arts training, which will allow you to learn at a slower pace and help you practice proper technique. This is especially important if you are new to exercise.

Cardio-kickboxing gear

Wear comfortable exercise shorts and a non-restricting t-shirt or tank top. Women should wear a sports bra. Bring a towel and water to class. (Drink plenty of water before, during and after your workout.) You may also want to bring a mat for floor exercises and wear a sweatband around your forehead.

Wear aerobic shoes or other lightweight athletic shoes designed for pivots and lateral movements. You could risk a sprained ankle if you wear running or walking shoes on carpet, IDEA warns.

If you'll be hitting a bag or sparring, you'll also need wraps and gloves to protect your hands and wrists. Some cardio-kickboxing facilities sell these items, as do most sporting good stores. The wraps are long strips of absorbent cloth that are wrapped around your hands and wrists and secured with Velcro. Boxing gloves come in a variety of sizes and degrees of thickness.

Glossary of terms

Base move: Quickly shifting your weight from the ball of one foot to the other

Bob and weave: Shifting your weight back and forth while raising and lowering your torso from near-standing to near-squatting positions. With elbows bent, fisted hands are held in front of your face

Combination: A series of punches thrown in quick succession

Front Kick: A type kick where the foot is lifted straight out in front of you with your toe up

Hook: A punch in which you swing your fist around from the side in toward the center

Jab: A quick punch at face level in which the thumb is at a 45-degree angle.

Roundhouse Kick: A kick in which your foot and leg are swung up in such a way that your shoelaces hit the side of the target in front of you

Side Kick: A kick in which your lower torso is turned inward so that your heel lands on the target while your foot is parallel to the floor.

Uppercut: A biceps-powered punch that begins with your fist low and ends with your fist almost straight up