With circuit training you can work many muscle groups in a relatively short period of time and get an aerobic workout at the same time. Here's how circuit training works and how you can get started.

What Is It?

Circuit training consists of a series of exercises performed sequentially. At the end of a circuit you might repeat the circuit, or within a single circuit you might repeat each exercise two or three times before moving on to the next exercise.

Circuit training can include a combination of aerobic and strength exercises. An example of the mix might include jogging, jumping rope, push-ups, crunches, lunges, bench press, and squats. The cycle can take anywhere from 15 minutes to over an hour to complete.

The Strength Training Component

Strength training (or weight training) is often included in circuit training.

"It is important to remember that you should be able to perform 8-12 repetitions (reps) of the weight exercise if you are integrating it into your training session," says Michael Wood, CSCS, director of the Sports Performance Group in Boston, Massachusetts. "Circuit training is meant for general conditioning and is great for people who want to decrease their percentage of body fat," says Wood.

Who Can Do Circuit Training?

Anyone can do circuit training. If you have never exercised or are just getting started again, circuit training is the quickest way to increase your lean body mass. As always, consult your doctor before beginning an exercise program, and then consult a trainer about developing a circuit.

"I have worked with all levels of athletes," says Wood, "and circuit training adds a variety that everyone can appreciate. A mundane exercise program can make developed athletes prone to injury because they become bored and lose focus on technique. To the beginner, monotony in an exercise program will eliminate the desire to work out."

The Variety

"You can circuit train anywhere," says Chantel Durelli, an ACE-certified personal trainer in Hollywood, California. "I'll bring my clients to the UCLA stadium and have them run up the stairs, do a chest exercise with elastic bands, then have them run down and do crunches. They'll run back up and do curls, then down and do lunges. Two days later we'll go to the beach and jog, incorporating an exercise at each lifeguard chair."

You can do circuit training at home, at the gym, or wherever you exercise. Many towns have fitness trails with circuit training stations located at regular intervals.

Using All Your Muscles

You'll use all your major muscle groups when you circuit train.

"A good circuit includes an aerobic activity and specific exercises for each major muscle group," says Wood. "While I encourage clients to enhance their activities with circuit training, for many, it may be all they do during a busy month and it exercises their entire bodies."

Equipment Is Optional

The necessary equipment for circuit training varies from weight machines or free weights to almost nothing.

"There is a lot you can do with your own body weight, such as push ups, triceps dips, crunches, and lunges," says Shawn Thiboutot, CSCS, a trainer in Brunswick, Maine.

An Efficient Workout

The constant motion of circuit training burns a significant amount of calories.

"The biggest advantage (of circuit training) to my clients is the efficiency of the workout," says Wood. "You can burn more calories in half an hour of circuit training than most people do in an hour of weight training." Beginning exercisers should not feel pressured to move at a fast pace. It is not a race; just try to keep moving.

How Do You Circuit Train?

It's best to work with a certified trainer when designing your circuit-training program. A trainer can make sure you have a good balance of exercises that include all your major muscle groups. You won't need to work with the trainer forever just until you understand the routine and can perform it properly. For a veteran exerciser, this may mean just one or two sessions with a trainer.

"Beginners should just walk through the motions the first time so they know what to expect," says Wood. "A beginner routine should only have six to eight exercises." Most trainers recommend that beginners circuit train twice a week for 30 minutes. Three other days should contain other activities such as walking or hiking.

After a few weeks, increase the duration of the circuit by five minutes. The duration of the circuit training session should reach 45 to 60 minutes, three days per week.