Now, let's get to the weight machines. One of the selling factors of most gyms, including places such as Curves, is that they feature circuit strength machines. A circuit, as mentioned previously, is a trail or path around the strength machines. So, basically, you will go into the gym and use one machine at a time — someone at the gym will actually show you how to use each machine and explain (one hopes) which muscle each machine works.
Typically each machine isolates one muscle, so the rest of your body is technically at rest — sitting, usually — and the machine allows you to simply move one muscle or muscle group, which allows you to use a heavier weight. If you, for example, do a bicep curl with a dumbbell, you'll probably use five or eight pounds, but if you use a Nautilus machine (that's a brand name) you might be able to lift twice that.
The most important thing you should do and know about weight machines versus free weights is that the only thing that truly matters — truly — is your preference. There is no one right way to create a strength-training program, except, of course, to be safe, and we'll cover that in a minute.
Weight machines, like anything else, have pros and cons. First, they are quite effective — just as effective as free weights and bands. Second, they are actually very easy to use. Third, because the whole sequence is done in the order the machines are in, you don't have to think that much about what you have to do. Just follow the path — or circuit — and you're good to go.
The negatives to weight machines are few. First, if you aren't of average height, the machines might not be for you. They are designed to fit the “average male,” so if you're shorter than 5'8” (or much taller, for that matter) then you might feel uncomfortable or even not be able to do the exercises because your body won't line up with the machine properly.
You may find it boring to just move from one machine to the next. Some people like putting a little thought into their workout, and not everyone enjoys isolating one muscle at a time. It's much more engaging to have to use your whole body during any given exercise, even just a bicep curl, than to sit down and move only your forearms.
People who enjoy strength-training — and there are many men and women who swear by it — tend to mix up their routines, using free weights for some exercises, bands for others, and machines for others, based on how much weight they want to lift and how comfortable they are with any give exercise.