In recent years, elliptical trainers have taken the fitness industry by storm. What was once a fad relegated to late-night infomercials is now perhaps the most dominant piece of equipment in most gyms and personal training centers.

Let’s start the guide by taking a look at the differences between a treadmill and an elliptical trainer. The most immediate thing she will notice is that the elliptical is almost completely shock-free. This means you will no longer be subject to the lower joint pain most associated with running. Even a treadmill with great shock absorption and a brace belt, while better than running on pavement, will still put a strain on your knees and ankles.

On the other hand, a treadmill is much better for the specific training of runners and joggers. You can’t really train properly for a marathon on an elliptical. Although the feeling of an elliptical is walking or running, it is not as good as running.

Now, let’s take a look at the “pain” of running. Recent studies have shown that people exercise harder and longer on ellipticals because the perceived amount of exertion appears to be much less. The more “comfortable” an exercise is, the longer and harder someone will go. This is one of the main reasons why many seniors and older athletes have gotten used to the elliptical so easily.

Another obvious difference is the cross-training arms that most ellipticals have (with a few exceptions, like most Precor ellipticals). With the addition of the cross-training bars, the elliptical allows for an additional aspect of your training: strength training. Almost all fitness experts agree that all proper workouts need a strength training aspect and the elliptical melds this very well with cardio training.

Let’s talk about what to look for in an elliptical trainer. First, which is better, a front wheel or a rear wheel elliptical? Truth be told, they both work exactly the same. Anyone who tells you otherwise is just trying to see you list assets. They give you exactly the same training. The only real difference is if you’re a bigger person or if you’re on a lighter (or less sturdy) machine. In this case, the front units will definitely feel a bit sturdier. This is because when you exercise on an elliptical, you are throwing all of your weight forward. Having the transmission and steering wheel heavy in the front will help you balance. Larger flywheels are better as they tend to last longer and give the machine more robustness.

Most elliptical trainers have magnetic brakes and you don’t want to mess with anything else. The old friction-based brakes tended to wear out too quickly, so steer clear of the dinosaur machines that still use them.

Stride is one of the most important features of an elliptical because it has more to do with comfort. Longer strides are better on ellipticals, unless of course you’re a shorter person, but for most people, 18″ or longer strides are best. Personally, I think 20 to 21 inches are best for anyone up to about 6’4″. Anything shorter than 18″ will be uncomfortable for most people.

Pads: Make sure the unit you are looking at has articulating pads. The reason for this is that elliptical trainers with static foot pads (such as Tunturi units) can cause your feet to start to go numb over longer workouts. This is due to the lack of circulation caused by the static pedals. Look for pads that flex with your feet. You’ll thank sensei.

Things like programs, heart rate monitoring, and personal fans are nice, but the points above are the main things to consider. Also, get a taste of the feel of the way it rides on an elliptical. There are two varieties of mount: side mount machines (such as Precor 546 or Star Trac Rear Drive) and rear mount machines (such as Matrix E5x or Horizon EX44). Some people have a little difficulty riding from the side and should consider rear-wheel drive options. As with the position of the flywheel, rear-mounted versus side-mounted ellipticals work exactly the same way.

The best way to choose an elliptical is to go to a local gym or sports store and try them out. Be careful though, once you work out on a commercial-grade elliptical, it’s hard to transition to a residential-grade one. Top-of-the-line commercial ellipticals are from Star Trac, Matrix, Precor, and Life Fitness. The best home ellipticals include Horizon, New Balance, and Endurance. Fitnex and Spirit/Sole are great mid-range brands that do an excellent job of providing business-quality workouts for not much more than a residential price.