A stair stepper consists of a pair of foot pedals on a frame with handlebars or handrails. These are attached to an alternator with a chain drive. The alternator creates resistance, which supports your body weight as you step. At higher intensity workout levels, the foot pedals give you less support, so you’re forced step faster and higher as you strive to keep from bottoming out the pedals and ascend the imaginary “stair.”

The most familiar brand name of stairstepper machine is Stairmaster.

It’s a familiar sight at most gyms to see people propping themselves on the handrails while they use the Stairmaster. By using their arms to take the load off their legs, they’re reducing the intensity of their workout while the control console shows them burning calories at a high rate. Some models of stairstepper have addressed this problem by replacing the full set of handrails with a wishbone-shaped handlebar in front of the user that’s only useful for balance. However, bigger people may not feel as secure on these machines because they look less stable. It’s tempting to cheat when your workout isn’t going well, but supporting your body with your arms on a stair stepper defeats its purpose.

A stair climber looks like a three-step escalator with a railing on each side. Stairclimbers have a revolving staircase that cycle endlessly toward the bottom of the machine as you climb toward the top. The stairs revolve from 30 to 156 steps per minute, which ranges from a very slow walk to a dead run. You intensify the workout by pushing a button on the console and speeding them up.

A stairclimber could very well be the most intense workout you can get on a piece of exercise equipment. Each step is a full 8 inches high, and when the machine is humming along at high speed, you’ll be sweating and gasping for breath in a hurry. Cheating by leaning on the handrails won’t decrease the intensity of your workout much on a stairclimber. A popular item in most gyms, they nonetheless are getting hard to find as many manufacturers have stopped making them. Maybe the commercial gyms have stopped buying stair climbers because they’re trickier to maintain under constant use than less complex pieces of equipment. Or maybe the workout they give you is too much for all but the most dedicated gym rat.

Stairmaster is the best known manufacturer of stair climber machines. The earliest model was named the Stairmaster 4000 PT Gauntlet, which is an appropriate name for the intense workout this machine provided. Later designs included the Stairmaster Stepmill 7000PT. Although hard to find new, refurbished models are available at reasonable prices with short-term warranties. A used Stairmaster can be a terrific investment and a great fitness machine to add to your home gym.

Because your feet never leave the footbeds, elliptical fitness equipment is zero impact. Many runners with knee problems have switched over to ellipticals so they can continue the intense aerobic workouts they love. At the same time, elliptical exercise is considered weight-bearing exercise despite its lack of impact. Any time your body is pulling against gravity, it’s bearing weight—good news for women (and many men) who are concerned about osteoporosis.

The majority of elliptical exercise equipment has a pair of moving handlebars in addition to the footbeds. These handlebars are designed to coordinate the motion of your arms and legs so that you’re pulling toward yourself on the side you’re striding with. This simulates the motion of walking or running and gives your upper body a moderate workout along with your lower body. For this reason, they have been dubbed elliptical cross-trainers.

Most elliptical machines have an electric alternator that controls the unit’s resistance. Unlike a treadmills, where the motor makes the belt go faster, the alternator on an elliptical trainer tries to slow you down, increasing your exertion by making your legs work harder. Some cheap ellipticals use a simple friction system to increase the resistance.

One important feature to look for in elliptical equipment is synchronized handlebars with a mechanical ratio that allows your arms to move more slowly than your legs so they can do more work. Machines with a 1-to-1 arm-leg speed ratio simply take your arms along for the ride because the handles move so quickly.

Some of the most popular brands of elliptical exercise machines are Life Fitness, Schwinn, Nordictrack, Octane, Proform, and Ironman.

Ellipticals are popular in smaller living quarters because they’re not as heavy as other workout machines, and they’re more compact. They’re also not as noisy because there’s no impact and therefore no pounding noises of footsteps for your neighbor to put up with while you’re working out. With fewer moving parts, they’re less expensive to maintain, too. Unlike treadmills, there are no expensive belts to replace every few years. If you’re on a budget, take a look at the mini elliptical trainer. These are sold under many brands and are very small and less expensive than the full size models.

You can read and watch TV on your elliptical machine even at full speed, because only your arms and legs are moving. However, if you’re in physical therapy or have problems walking, you need to be very careful which machine you buy. With some models, you have to climb up a little bit to get your feet into the footbeds, and once you’re striding, you have to stay coordinated and keep your legs moving. Some people in PT love their ellipticals, but others aren’t able to use them. Choosing the right model is very important.

Shop online for elliptical trainer reviews so you can pick the right features and prices when you’re ready to buy.