Electrical stimulation devices are safely and effectively used all the time in rehab and physical therapy settings, under the supervision of trained professionals. But I have never read a study about the safety and efficacy of these devices when used by consumers, so I can't say for sure how you would do with it at home. The more important question is if the device is worth the money. Here's what you need to consider.

Electrical stimulation does work to increase strength, tone, and even girth in some cases. In addition, there may be positive muscle enzyme changes that occur as a result of its use. But as I said, electrical stimulation is used primarily in rehab situations, when the pain of dynamic exercise makes traditional exercise difficult, and it's almost always used simultaneously with, or followed up with, dynamic strengthening. As tempting as it may be to buy one of these devices, there are many reasons why you'd be better off saving your money, or spending it on exercise equipment or a gym membership.

1. To get a training effect from electric stimulation, you'll need at least 30 minutes of stimulation, plus the time it takes to apply the electrodes. You can get a better workout in less time with traditional exercise.

2. The benefits of electric stimulation tend to be muscle positional. In other words, you get a response, but primarily at the angle that the joint is positioned when you use the machine. So if you put electrodes on your biceps with your arm extended, you will be stronger at that position, but you wouldn't necessarily end up stronger for dynamic activities like lifting objects. In some studies of electric stimulation, the subjects exercise dynamically or isometrically while using the electrodes to counter this effect.

3. There is no cardiovascular benefit from using electric stimulation. That means no reduction in your risk of heart disease, diabetes, or other health benefits of aerobic activity, plus electric stimulation does nothing for management of weight if that's an issue for you. It also won't give you the feeling of well being, reduced stress, or energy that comes with regular physical activity.

4. Neurological patterning has a large effect on strength development and it is missing with electric stimulation. When you exercise, the brain sends signals to the muscles to contract. As your brain learns, or relearns (depending on your conditioning level), how to send signals to the muscles, you get stronger. That's why people who start weightlifting always get stronger in the first few weeks without necessarily getting bigger. There's a very important neurological component to strength development that is absent with electric stimulation because the stimulation is localized.

The only benefit I could possibly see to the stimulators, and it's a real stretch, is if the device cued people to do some abdominal exercises ("Fast Abs" includes instructions sheets for six different workout programs). There are better cues for exercise, but if buying the device worked to get people to exercise, then it might be of some value.

In the final analysis, people need to know that simply putting the belt on and running a current through their muscles is not going to tone them and burn excess fat the way they would like, the way the manufacturer promises, or the way the models in the advertisements make it look.

Reviewed by Michael W. Smith, MD , March 4, 2002.