Professional athletes, working mothers, and the guy playing in the Sunday softball league have all relied on one piece of cardiovascular fitness equipment to strengthen, rehabilitate, and improve their quality of life.

At 36, Ellie Snyder, a certified personal trainer in Fairmont, W. Va., is a role model for exercising the body and mind, particularly during difficult times. Diagnosed with multiple sclerosis in 1995, the working mother of two remains committed to regular exercise in an effort to manage her MS symptoms and enhance her way of life.

Chad Tracy earns his living based on his physical performance. The professional baseball player for the Arizona Diamondbacks was recently sidelined from a knee injury. Both Snyder and Tracy, though at the opposite end of the physical fitness spectrum, have relied on one piece of cardiovascular fitness equipment – the Arc Trainer from Medway, Mass.-based Cybex – to strengthen, rehabilitate and improve their quality of life.


Others – from the Olympian swimmer focused on increasing her heart rate by 100 (from 70 to 170) in less than 30 seconds, to the 70-year-old recent retiree working his way back from a knee replacement – use the Arc Trainer for an impact-free exercise that works the right muscles without overstressing the body.

“I came off a knee injury a year ago, and using the Arc Trainer allowed me to train at a higher intensity for gaining strength and fitness in a pain-free environment,” says Tracy. “I was able to prevent any swelling in my knee that would have set my training back during my off-season program.”

Building on Progress

When Cybex introduced its Arc cross-training cardiovascular machine five years ago, its mission was to build a breakthrough piece of equipment that would change the fundamental motion used in elliptical machines and provide impact-free exercise and maximum training effect on muscles, without overstressing the body.

Elliptical trainers, introduced at health clubs in the mid-1990s, had increased in popularity because they delivered a low-impact workout and allowed simultaneous upper body exercise. But Cybex engineers felt there was a better mousetrap in the cross-training category that needed to be built. However, getting there was a journey.

Cybex engineers set their sights high in creating an advanced piece of cardio equipment. By studying many popular elliptical machines and analyzing and testing their mechanics, they learned that ellipticals did not offer the varying intensities for a superior workout. So Cybex instead used the treadmill as the benchmark product and took attributes from the design, along with that of other Cybex products that used a similar upward path of motion.

Designing a product that offered high and low levels of intensity, as well as a variety of workout ranges, was within reach for Cybex International, a manufacturer of premium exercise equipment for commercial and consumer use.

“Most non-impact cardio machines can’t provide the level of intensity we were looking to achieve and also provide low impact and subsequently less stress on the joints,” says Ray Giannelli, Cybex senior vice president of research and development. “Biomechanics experts often look at a pattern of motion and try to anticipate which direction the forces are applied.”

He continues, “Through research, Cybex learned that the pattern of motion doesn’t necessarily dictate direction of force. In doing so, we focused on adding inertia to the movement and realized we had to develop our own tools to measure the force to better understand the biomechanics,” says Giannelli, who spent six months from concept to design and delivery of a prototype Arc Trainer.

Cybex succeeded in its mission with a “breakthrough” award-winning design in biomechanics. The Arc earned the prestigious Nova7 Best Product Award twice and was named Best Product of the Year by Madison, Wis.-based Fitness Management two years in a row.

A Machine Apart

But what sets this “un-elliptical” cardio machine apart from others? The Arc pattern of motion provides a greater calorie burn without discomfort. Its broad incline and resistance range, consistency in proper positioning, and correct load application means that Arc workouts burn more calories and strengthen muscles without putting strain on the joints.

“The Arc engages the muscles that demand a high amount of energy, yet provides a minimal strain on the knees, back, and hips. In doing so, the Arc yields higher oxygen consumption during workouts,” says Paul Juris, executive director of the Cybex Institute and prominent kinesiologist. “With an exceptionally broad resistance range from zero to 900 watts, the training experience can be as gentle or intense as desired for the user, making it an ideal offering for both younger individuals, in addition to those who are part of our aging population.”

The Arc Trainer has become a prominent piece of cardio equipment at fitness clubs, resorts, and rehabilitative centers around the globe, due to its user-friendly “correct arc of motion” design and superior biomechanics and ergonomics. It engages the muscles that demand a high amount of energy – yet provides minimal strain on the knees, hip, and back – and it accommodates the first-time exerciser or the professional athlete, as well as people of all varying degrees of physical fitness levels, and those with disabilities.

“Perceived effort and joint discomfort are totally different on the Arc Trainer, compared with elliptical machines,” says Jeremy Boone, a certified strength and conditioning specialist, who works with a vast array of exercising populations and is also part of the off-season program for the NFL Carolina Panthers.


“I have clients who just can’t push themselves hard enough on elliptical trainers without it becoming too uncomfortable, or even painful; but on the Arc Trainer, they can work as hard as they want without experiencing any pain or discomfort. Even athletes with previous or rehabbing knee injuries feel that the Arc Trainer gives them a great workout without any knee pain.”

Dubbed a true cross-trainer (and often incorrectly identified as an elliptical), the Arc Trainer provides the added versatility of upper body training, while keeping the variable incline of Cybex’s advanced stride technology, which naturally coordinates movement between upper and lower body through all levels of incline to maintain correct posture for a superior workout.

The Arc Trainer offers varying resistances and inclines, which provide an unmatched number of workout combinations – elements of a climber, hiker, and skier – allowing users to focus on their own specific needs, targeting the same areas in different ways to build muscle, burn calories or both.

“The Arc Trainer has tremendous breadth and is versatile enough to accommodate any and every workout need I have,” adds Snyder, who has increased her exercise frequency since her MS diagnosis in 1995.
“I have found no other piece of fitness equipment that can do that. On days when fatigue sets in, I can keep my routine moderate, like a slow stroll in the park, and on days when I feel great, I can really crank it up and increase my workout to an equivalent of climbing Mt. Everest.”

The Machine-Patient Connection

The Arc Trainer, like all Cybex products, is designed and engineered using exercise science to reflect the natural movement of the human body. The footplate of the Arc Trainer moves along an arcuate path, while remaining level to the ground throughout the motion cycle. The elliptical trainer footplate moves along an ellipse, while the footplate tilts forward at different points during the movement cycle.

A biomechanical analysis of these patterns was performed at Florida Atlantic University in Boca Raton, Fla., revealing differences in the force trajectories created during exercise on these devices. While the forces on the Arc were more vertical in direction, those on the elliptical were directed more horizontally, leading to significant differences in torque loading at the knees, hips, and back.

A follow-up study conducted by the University of North Carolina at Charlotte compared the physiological and metabolic costs, and perceived effort, between the Cybex Arc Trainer and a popular elliptical trainer.

“The Arc Trainer’s perceived effort and metabolic effects were compared against a popular elliptical trainer, and the principle difference between these two devices was the movement pattern of the footplates,” notes Juris. The purpose of this study was to determine if subjects using these devices would detect differences in perceived exertion and joint discomfort, and to see whether the mechanical loading differences between the machines would result in disparate heart rate and metabolic responses to exercise.

Maximal oxygen consumption was first established on the two devices, for 18 volunteers. Subjects then exercised at steady state levels of 55 percent, 65 percent, and 75 percent of their maximal oxygen uptake (VO2 max) on each device. At each level, heart rate data were collected, and subjects reported on overall perceived exertion, as well as indicators of perceived discomfort at the low back, hip, and knee.

At all levels of training intensity, subjects on the Arc reported significantly lower rates of perceived exertion. Additionally, there was a notable decrease in joint discomfort on the Arc when training at higher intensities. Maximum oxygen consumption for the Arc and the elliptical were not significantly different, but heart rate responses on the Arc were significantly lower at the three predetermined levels of VO2 max. When data were normalized for heart rate, subjects consumed more oxygen on the Arc than on the elliptical.

One notable conclusion that emerged from these studies is that “non-impact” does not mean stress-free. “People often think that just because a device eliminates impact, they are protected from stress,” says Juris. “In fact, there are many forms of stress that are imposed on the body, sheer being a major one, and these can be just as harmful in the long run. Devices that are designed to simulate motion often overlook the forces that are imparted on the user. When devices are created to properly manage the forces, the result is a better exercise experience with minimal stress.”

With the help of the Cybex Arc Trainer, a woman with non-diabetic neuropathy was able to push her crutches to the side and in her now surefootedness is dancing with her husband once more. Her pain has been greatly alleviated and her health and stamina are developing.
There are no two people that are exactly the same – and in the case of the Arc Trainer, there is no other cardio machine quite like it.

— Lynn Luczkowski is a CT-based freelance writer and the owner of L2 Communications in West Hartford, Conn. Questions and comments can be directed to editorial@therapytimes.com.