Cardiovascular equipment has long been a staple in fitness facilities of all shapes and sizes. Cardio machines are inviting to all levels of exercisers for one main reason: ease of use. Because most cardio machines simulate everyday activities, such as walking, climbing stairs or riding a bicycle, even the most novice exercisers can feel comfortable using them.

Technology has greatly enhanced the cardio equipment offerings. Most machines incorporate computers and software that enable users to gather feedback about their exercise session (calories burned, distance traveled, time exercised, etc.) and to select various workout options, such as interval-type programs (e.g., Hill and Random) that range in difficulty throughout an exercise session. Some cardio machines include interactive heart rate programs that change resistance automatically to keep exercisers within their target heart rate zones for safe, effective training.

Despite the multitude of programs available, boredom is still a common complaint among exercisers. Accordingly, variety is a key factor in equipment selection. Even the most basic on-site fitness facility should take a "one of each" approach including at least one piece of equipment from each of the major cardio equipment categories; moderate traffic facilities should have at least two treadmills.

The major categories of cardiovascular equipment include treadmills, stationary bikes, stair climbers and elliptical or cross-training machines. Additional equipment to consider, if space and budget permit, include rowers, cross-country ski machines and rock climbing walls. A brief description of each category, as well as buying guidelines and other considerations, follow.

3-4 pieces of equipment $9,000 to $18,000

• 1-2 treadmills
• 1 exercise bike
• 1 stairclimber OR
• 1 elliptical machine

5-9 pieces of equipment $18,000 to $35,000

• 2-3 treadmills
• 1-2 exercise bikes
• 1-2 stair climbers
• 1-2 elliptical machines

10-20 pieces of equipment $35,000 plus

• 4-6 treadmills
• 2-6 exercise bikes
• 2-4 stairclimbers
• 1-2 elliptical machines
• 1-2 specialty machines
  (rowers, cross-country ski machines, rock climbing wall)

The treadmill is the most popular of the cardiovascular equipment categories - usage has increased by 720 percent over the past ten years. This probably should not come as a surprise, since walking, jogging and running are among the most prevalent forms of exercise worldwide.

Facility operators should invest most of their time and budget into finding a quality treadmill that will meet the needs of their clientele. When deciding upon a treadmill, providing your sales representative with as much information as possible is important. For example, what is the potential number of users? What is the average weight of the exercisers? What is the age range of your user population? What is the anticipated average total daily use (hours per day)? This information enables the sales representative to identify the most appropriate equipment for your facility.

The second most popular cardiovascular machine is the stationary bike. Exercise bikes are the least expensive type of cardio equipment, and with a small footprint, are also space-efficient. Also,many stationary bikes are self-powered, allowing maximum flexibility in laying out a fitness facility.

Two general types of stationary bikes are available: upright and recumbent bikes. The frames of upright models resemble ordinary outdoor bicycles, while recumbent bikes allow exercisers to sit in a semi-reclined position behind the pedals. Recumbents typically feature wider seats with seat backs, which provide additional comfort. Recumbents are particularly good for rehab or older users. If budget or space constraints only allow one or two exercise bikes, a recumbent may be the logical choice.

Stair climbers are also available in two styles, classified by their stepping motions. Independent stair climbers have pedals that are "free floating." When an exerciser stands on the pedals, they both sink to the ground until the exerciser initiates the climbing motion. Conversely, dependent stair climbers feature pedals that are linked together. When the exerciser steps down on one pedal, the other goes up.

There is no clear-cut indication which style is better - it is largely a matter of exercisers' personal preferences. Independent action, which requires more skill and coordination, tends to appeal to serious exercisers. Beginning exercisers, however, may feel intimidated if they have trouble learning the coordination and may prefer the simpler, dependent stepping action.

The newest category in commercial cardio equipment is the elliptical machine or cross-traininer, so named for the egg-shaped or elliptical pattern the pedals follow. All elliptical machines work the muscles of the lower body, with forward and backward pedal motions that minimize impact to ankles, knees, hips and lower back.

With some models, users can adjust the incline during the workout for added variety and effectiveness. Other cross-trainers offer upper body exercise through arms that move in synchronization with the foot pedals-providing a total-body workout.

Elliptical or cross-training machines are incredibly popular with exercisers and should be included in even a small-scale fitness center.

Specialty cardio equipment outside of the major categories can round out your offerings and add variety for exercisers. Rowers, cross-country ski machines and rock climbing walls are just a few examples of other popular cardio equipment. In order ro choose the right machines, think about the goals for your facility. To accommodate a wide variety of users, install a variety of cardio equipment. High-traffic facilities may require more duplicate machines. To set your facility apart from the others, consider adding one or more specialty pieces.

Knowing the benefits and dynamics of each type of cardio equipment will help you make the right purchases for your users-and keep them using your facility. And, the more they use it, the more valuable an amenity it becomes.