A total body workout during your lunch hour? With circuit training, it's possible. During circuit training, you perform a series, or "circuit," of weight-training exercises (or "stations") using low weights and high repetitions with minimal rest between sets, to keep the workout intensity—and your heart rate—up. If you organize your circuit effectively and move quickly from station to station—no waiting for equipment or resting between push-ups—you'll reap an excellent combination of strength, aerobic, and anaerobic benefits in less than a 30 minutes.
1. Select your stations. Circuits can be designed around as little or as much equipment as you have available, from a basic 45-lb. barbell to a complete gym. Some exercises, like squats and crunches, are useful no matter what your fitness goal, but if you're training for a specific purpose, you should also try to include a few exercises that are sport-specific. If you're a runner or biker, do lunges. Swimmers can do overhead military presses, biceps curls, or dumbbell flies. You can also include one-minute intervals of cardio exercises, like jumping rope, jumping jacks, or squat thrusts, in between the weightlifting sets to further boost your heart rate.
2. Set your targets. Organize your circuit workout, either by setting a target number of reps for each exercise or a specific length of time to spend at each station (for example, doing push-ups for a minute). I don't recommend doing timed circuits, because people tend to cheat by working slowly, doing fewer reps than they should. Working quickly (though always with controlled movements) and doing high numbers of reps are essential to circuit training—that combination is what makes circuit training an effective cardiovascular workout. Start with 25 to 30 reps for each upper body weight exercise. For the lower body, 15 to 20 reps for each exercise should be enough, because these exercises tend to be slower and to use your weight as added resistance.
3. Choose your weights. Use enough weight for each exercise so that you're able to achieve fatigue during every station, but not so much that you can't complete your target number of circuits. To minimize transition time between stations, I generally advise beginners to use one weight for all exercises in the circuit. A starting weight of about 25 percent of your body weight is generally plenty. The last few reps should be difficult but not painful. Working at this level should keep your heart rate at about 75 percent of maximum heart rate. When the workout ceases to be a challenge, add more reps and time at each station. Once you can add 5 to 10 reps per exercise, you're ready to increase the weight by five pounds and return to your original number of reps.
A few guidelines to keep in mind when setting up a circuit:
Alternate between upper- and lower-body exercises. This allows the muscles more time to recover between exercises, resulting in greater productivity without slowing down the circuit. A circuit should work the entire body.
Include large muscle exercises. Exercises like squats and step-ups add intensity to your workout and keep your heart rate elevated.
Keep the pace. Set a minimum number of repetitions or length of time for each station.
Minimize transition time between stations. You should have only five to 10 seconds between exercises. (No sneaking in a little extra recovery time!) Don't try to circuit train during peak hours at the gym or you'll end up waiting for stations, adding time to your workout and reducing the cardiovascular benefits of the training. To save time, limit the equipment you use in your circuit. There are plenty of exercises you can do with just a barbell or a pair of dumbbells.
Here's a sample circuit requiring only a barbell. If you're moderately fit, try using a barbell weighing 20 percent of your body weight to start. You should be able to get through this circuit two or three times in 18 to 26 minutes.
40 crunches
15 squats
30 bent-over rows
15 step-ups (per leg) on a 12- or 16-inch bench
30 push-ups
15 squats
30 arm curls
40 bicycle crunches, each leg
30 upright rows
30 bench presses