If you're after a full body workout, the only piece of exercise equipment you need is an elliptical training machine. Elliptical trainers are low-impact machines that don't strain your muscles or any part of your body beyond its limits. And the one muscle that the elliptical machine works out the most is the heart. Its performance is actually comparable to the treadmill, which is also a cardiovascular exercise device, although proponents of the trainer claim that the additional upper-body workout provided by the trainer makes for a more well-rounded exercise session.

The one thing a treadmill may have as an advantage over elliptical devices is, it provides a more intensive lower-body workout. This is especially true of non-automatic treadmills, or treadmills that are pretty much just… rubber treads wrapped around steel cylinders, and go round as you walk on them. Non-automatic treadmills provide greater resistance, so leg and thigh muscles are bulked up faster. If you're a serious marathon runner or walker, and part of your regimen is working out indoors, keeping a non-automatic treadmill might be more to your advantage.

For the rest of us normal folk, however, an automatic treadmill is more highly recommended. For one thing, it won't give you legs of steel like a marathon runner, the way a non-automatic treadmill would. Certainly not if you want to look good in that short-hemmed cocktail dress! For another, it'll be easier on your joints and heart. Less tension on the legs makes for more leisurely exercise, giving your body more time to adjust to the subtle changes in exertion routine.

It's argued that an automatic treadmill and an elliptical trainer may have similar benefits, since elliptical trainers are almost always automatic, as well. Automatic treadmills can also come with all the other nifty functions of top-grade trainers, such as heart rate monitors, adjustable speeds, etc. And if you're just worried about the full body workout, you can exercise on a treadmill even without something to hold onto. It just won't be as easy, or as natural for your body.

When you're looking to buy just one exercise machine for your personal use, and you want to weigh the advantages between treadmills and elliptical training machines, keep your specific needs in mind; these will shape the criteria that will help you choose.