An elliptical trainer (also cross trainer or simply elliptical) 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 set by the user. Most elliptical trainers work the user's upper and lower body (although some models do not have moving upper body components). Using an elliptical trainer is designed to provide a cardiovascular workout rather than building muscles.
They can be self-powered by user generated motion or need to be plugged in 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.
It should be noted that there are two major types of elliptical trainers, "front-drive" and "rear-drive" with the former having the elliptical drive mechanism at the front of the machine and the latter having the elliptical drive mechanism at the rear of the machine. The photo above depicts a commercial rear-drive machine.
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, resistance and stride length over the course of a workout according to a preset program. Some trainers can be driven in a reverse as well as in a forward direction. Elliptical trainers 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 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.
Some manufacturers produce commercial models which focus on durability and are made to withstand the more frequent use of the fitness club environment. These units typically sell for well over $4,000 (US), offering greater durability and programming than the typical home user would ever need.
An elliptical cross trainer is comparable to a treadmill in its exertion of leg muscles and the heart. 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.
A recent study by the University of Idaho shows that varying the stride length on the elliptical trainer can recruit a larger variety of muscle groups. The study also showed that as the stride is lengthened, more calories are burned without any higher rate of perceived exertion by the user. This study lends credibility to the claims made about the adjustable stride length feature on some newer ellipticals.
By using the elliptical without holding onto the handgrips, the user can improve his or her motor fitness and balance. In this position, the core muscles are held in a state of constant tension. This hands-free position also promotes better posture.
While gripping the handrails in a smooth controlled motion, the user should stride either forward or reverse, working through a full natural range of movement smoothly and continuously.