To save time, I have been doing multiple sets -- say four different exercises in a row -- and then repeating them for three sets. Is this an okay thing to do, or should I do a set of a particular exercise, wait a minute between sets and then do the same one again?

What you describe is called super setting or giant setting, and it's a standard weight-lifting practice. Although some machine manufacturers and gym owners discourage it (extra sets mean longer waits for equipment), most seasoned weight-lifting veterans do it regularly. I think that super setting can help you pack more work into your workout.

Doing multiple sets is a good time-saver and can be an effective muscle-building technique. When you super-set opposing muscle groups -- groups on opposite sides of the same joint -- you cut down on rest time because you're resting one muscle while working another. So, for instance, you could do a set of flies for your chest immediately followed by a set of pull-downs for your upper back. You can also super-set the same muscle group to work that muscle to full exhaustion. A set of military presses followed by a set of lateral raises and then a set of front raises is a killer routine for your shoulders.

Another type of multiple-set workout with limited rest between sets is called circuit training. In this type of routine, you simply do the same exercises you would normally do within a workout, but you move quickly from exercise to exercise with little or no rest between sets. When you complete a circuit, you can run back to the beginning and start all over again. A warp-speed workout like this can condense an entire hour's worth of weights into as little as 20 minutes -- and leave you dripping with sweat too.

I recommend alternating each upper-body exercise with a lower- or middle-body exercise so you don't tire out one half of your body prematurely. It's easiest to circuit-train with weight-training machines, but there's no reason you can't do a decent circuit with free weights or exercise bands. I suggest substituting one regular workout a week with a circuit-training routine if you're feeling bored or you're trying to blow past a training plateau.

Although circuit training is ideal for time-challenged exercisers, it does have its limitations.You won't see the strength gains you'll see with traditional weight-training methods, partly because the blistering pace requires you to reduce your typical poundages by 20 percent or more. And if you're looking for some aerobic benefits from this type of workout, sorry, but research shows they're limited.

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