The latest in popular ellipticals For all the hoopla over "natural" and "functional" fitness movements, one of the most popular workouts for all body types and athletic levels continues to be the wholly unnatural egg-shaped stride of the elliptical machine, invented by Precor less than 20 years ago. As smooth and joint-friendly as cycling and almost as calorie-burning as running, the elliptical offers an unmatched all-body aerobic workout in a number of creative variations, from front-drive to rear-drive, electronic or mechanical, and standing or seated. All of them have the famously addictive oval gait pattern that now seems as natural as the circular pedal stroke of a bike, which, come to think of it, was a completely unnatural act until it was invented 150 years ago. Steering-wheel feel Yowza Captiva: Adjustable-stride dual-action machine with side-to-side arm motion. Available only on the Web from a Florida company that has built fitness gear for 30 years and introduced the Yowza brand in 2008. Likes: A smooth, solid feel (rated for a 400-pounder) with a very enjoyable motion. Combining a rear-flywheel layout (similar to that of Life Fitness and other companies) with the side-to-side handlebar movement feels surprisingly pleasant and natural. The motion, which is vaguely like turning the steering wheel of a car, seems to do a good job of hitting the shoulders and the core. I felt like I could go for an hour. In fact, the man whose home I tested it in, Upland engineer Jasen Shorter, said he's done an hour a day on it since last July and has lost 80 pounds. The stride length adjusts from 18 to 28 inches with the push of a button. Loaded with features, it includes an iPod port, speakers, a fan, nine programs, a 0%-to-50% adjustable incline and a Polar heart-rate monitor. Maximum recommended user weight is 400 pounds. Dislikes: No showrooms. You have to test it at someone's home, buy it online and assemble it yourself. Shorter said that it took him five hours to put it together. Price: $1,999. http://www.yowzafitness.com Best seat in the house Inspire CS1 Cardio Strider: Seated elliptical machine. Likes: Although the step-through recumbent design is ideal for elderly and plus-sized exercisers who may have difficulty standing, the CS1 is a good workout for anyone. It's a good, low-cost alternative to more expensive seated ellipticals from market pioneer Octane, Nustep and Inspire's own CS2, which is $500 more (reviewed here positively a couple of years ago). Quiet and smooth, the enjoyable back-and-forth, slightly curved foot motion encourages pushing through the hips to lessen knee strain. The simple but effective console has 16 levels of resistance and counts calories, distance and time. Maximum recommended user weight is 300 pounds. Dislikes: None. Price: $1,295. http://www.inspirefitness.net Runaway train Spirit Fitness e•Glide XG400 Spinner: A rare mechanical elliptical with a dual-action front-drive system that is patterned after a spin bike with an exposed 30-pound flywheel. Likes: The inertia of the heavy flywheel gives it an exhilarating runaway-train momentum that made me not want to stop. A hand brake is used to slow the wheel. The smooth, solid feel applies while moving your legs in the reverse direction too. The remarkably smooth motion eliminates bumpy, up-down bobbing typical of some other brands. A natural stride is aided by the 2-degree cant of foot pedals, designed to add comfort. Includes an easy-to-read, adjustable-tilt console with a heart-rate profile chart (a strap is included), iPod jack and speakers, a fan, 10 programs and 20 levels of resistance. Dislikes: No adjustable stride length or adjustable step motion (but I didn't miss it). Price: $1,999. http://www.spiritfitness.com Budget blaster Vision X10: Economy, feature-laden, dual-action front-drive model from a venerable fitness brand. Likes: One of the smoothest, most stable, most feature-packed ellipticals for less than $1,000. A key to the comfort is the 20-inch stride length, more natural than that of its shorter peers. The X10 features a 21-pound flywheel, contact heart-rate grips on the handles and a easy-to-read console with seven programs, 16 levels of resistance and a full range of feedback metrics. Price: $999. http://www.visionfitness.com Wallack is coauthor of "Barefoot Running Step by Step" and "Bike for Life: How to Ride to 100."