An elliptical trainer (also cross trainer) is a stationary exercise machine used to simulate walking or running without causing excessive pressure to the joints, hence decreasing the risk of impact injuries.
Elliptical trainers offer a non-impact cardiovascular workout that can vary from light to high intensity based on the resistance preference. Most elliptical trainers work the user's upper and lower body (although some models do not have moving upper body components), although using an elliptical trainer is designed to elevate the heart rate more than building muscles.
They can be powered with AC electricity for adjustment of motion and/or for supplying their electronic consoles and resistance systems. Current models incorporate adjustable resistance via friction belt (obsolete), magnetic or electromagnetic devices.
On some models, the incline of sloping roller ramps beneath the pedal-links can be adjusted to produce varying pedal motion paths. The result of such adjustment changes the burdens on various muscle groups in the legs. Some mechatronic models can vary both the incline and resistance over the course of a workout according to a preset program. Some trainers can be driven in a reverse and forwards direction.
Ellipticals are primarily driven via the legs, and most are combination designs having handle-levers attached to each pedal-link for the purpose of enabling a burden on the arms to provide a secondary source of driving power. The user grips the handles below shoulder height and pushes/pulls them while shuffling the feet back and forth within their "elliptically" (misnomer) shaped paths. Thus the oscillating handle motions are dependently coordinated with the constrained pedal motions. Poorly designed machines are too dependent on the user's leg power, producing excessive handle speeds as a result of mechanical ratios that do not provide enough advantage to the handle-levers. Consequently such machines feel to the user like their arms are simply going along for the ride, rather than sharing in the work. The better models offer a harmonious combination of arm and leg exercise in the correct ratios.
Many consumer models found in sporting good and big-box retail stores can only handle users weighing no more than 250 lbs, and cost $1000 (US) or less. Higher-end consumer elliptical machines, like the Quantum Fitness,Precor, Life Fitness, and brands found in specialty stores, can accommodate users up to 400 lbs, and range in price from $1300 to $5400 (
An elliptical cross trainer is comparable to a treadmill in its exertion of leg muscles and the heart. However, because the user's limbs remain in continuous contact with the machine, its operation limits the dynamic loading of bones and joints to generally harmless levels. This non-impact aspect appeals to those with recent injuries, chronic knee problems, and the obese, who cannot tolerate a treadmill. Ellipticals produce an intermediate range of leg motion between that of stationary bikes and treadmills.
There are claims that the dual action exercise of an elliptical trainers can actually be more efficient in burning calories. The logic is that by exercising more muscle groups simultaneously, a more intense workout can be achieved in less time. It is also suggested that the perceived rate of exertion is lower. However, other studies have shown that the rate in which calories are burned on an elliptical trainer is similar to that on a treadmill.Regardless, elliptical trainers are growing in popularity. One reason may be that because the person who is exercising is not taking his or her feet off of the pedals, an exercise can be done at a gentler rate, still getting the same amount of results as a treadmill.