Elliptical exercisers - ratings.(Cover Story)(Evaluation)

Elliptical exercisers represent the marriage of a stair climber and a cross-country-ski machine. Your feet, on pedals, move in flattened circles; your arms, grasping handlebars, move back and forth (you can choose instead to grasp fixed handles, but the handlebars will move without you). The machines resist the motion of your arms and legs with a flywheel that is braked in one of two ways. On most machines designed for home use, the resistance comes courtesy of a band around the flywheel's rim. Most health-club ellipticals have magnetic resistance, which makes pedaling feel smoother.

Elliptical exercise seems to have caught on: Ellipticals are among the most widely used machines in health clubs, and the number of participants in elliptical exercise rose from 2.4 million in 1997 to 6.2 million in 2000, according to the Sporting Goods Manufacturers Association. Elliptical exercise is a good concept.

* The oval-shaped pedaling you do on an elliptical doesn't pound joints as running on a treadmill can. People over age 55 and those with knee problems are among the most devoted users.

* Ellipticals provide a weight-bearing workout, which helps protect bones against osteoporosis, unlike pedaling an exercise bike, swimming, or using a rowing machine.

* Unlike most treadmills and exercise bikes, a typical elliptical has movable arms that add an upper-body workout. The arm action won't necessarily build big biceps, but it helps burn more calories.

* Unlike cross-country-ski machines (a dying breed), ellipticals are easy to master without much practice or balance.

* In our tests, ellipticals rival treadmills for the number of calories burned with the same perceived effort.