Fitness equipment suppliers have been manufacturing cross trainers for years; designed to offer users a non-impact cardiovascular workout that, thanks to its movement pattern, reduces the pressure and stress placed on joints.
However, over time, research has shown that not all may be as it seems with the popular cardio machine and uncomfortable and high levels of load – or, in other words, stress - to the user’s joints may be generated by the running motion recreated by the cross trainer’s ellipse movement.
So while products have evolved and new technologies have been introduced to try and combat this, the patented design of the Arc Trainer has always offered an entirely unique cardio training option for the fitness industry, ever since the fi rst model was rolled out of Cybex’s US factory in 2002.
Arc Trainer vs. Elliptical
So is the Arc Trainer simply Cybex’s take on a traditional cross trainer? The answer is, ‘far from it’ – both are cardiovascular devices designed to eliminate the impact or shock caused by running, but that is where the similarities end.
The fundamental difference – and where the product’s name is derived from – is the patented Arc movement that makes the equipment so distinctive.
“Unlike other cross trainers, the Arc pattern of motion allows the hip and knee to move synchronously while the foot stays under the knee - so when the user pushes down and back, the opposite footplate is already up and in position, severely reducing the load and stress levels placed on key joints,” explains Dr Paul Juris, executive director of the Cybex Research Institute.
“The body’s position when using traditional cross trainers doesn’t allow for backwards force to propel movement so this instantly places the onus on the lead leg, which must push the footplate forward in order to continue the movement cycle,” continues Dr Juris.
“This force comes primarily from extension of the knee, resulting in high loading on the knee and virtually none on the hip.”
The Cybex approach
With its heritage in sports medicine and rehabilitation, Cybex’s approach is recognisable in every piece of its equipment; to design and manufacture products that are biomechanically
correct to produce optimum results but place minimum stress on the body.
“At Cybex we analyse and deconstruct motions, not just reproduce them, so when designing the Arc we focused on the load bearing phase of gait,” explains Dr Juris.
“This phase is also known as the ‘stance phase’ of running motion where force output is required, occurring when the foot moves from heel to toe and backwards. Because we are managing force not motion, there is balanced torque loading at the knee and hip, which activates the key muscles without impacting on joints.”
More calorie burn
In a study conducted by the University of North Carolina, it was demonstrated that the level of perceived exertion and the heart rate response of subjects exercising on the Arc Trainer was significantly lower than those exercising at the same percentage of energy expenditure on a rival cross trainer.
Dr. Juris explains the science behind this: “Users of the Arc Trainer experience higher cardiorespiratory and muscular responses with less perceived effort as a direct consequence of the biomechanical efficiency of the Arc.
“In other words, the Arc is better at activating the large muscles in the lower body – quads, glutes and hamstrings - so users can work at a higher intensity, thus resulting in a higher level of calorie burn.”
The unique Reverse Arc Motion, a patented advanced stride technology, moves legs in a biomechanically correct pathway and at no stage places the user’s toe behind the knee. This significantly reduces stress at the knee, whilst offering a complete range of motion for both the knee and hip.
The Arc also benefits from its Same Side Forward technology, which sees the arm and leg on the same side move together. This allows users to always maintain optimum posture during exercise, virtually eliminating stress on the back. In comparison, other cross trainers where the arms and legs move in opposite directions, lack the ability to maintain correct body positioning throughout the incline range.
Three machines in one
The Arc doesn’t just train for cardio and weight loss; its broad resistance and incline ranges allows users to focus on strength, power and endurance, targeting specific muscle groups.
“The Arc’s three exercise zones, Glide, Stride and Climb, refer to its incline levels, so you can go higher using a stepping motion to work the quads or switch to a lower level of incline with increased resistance to focus on the glutes,” explains Chris Rock, Cybex UK master trainer.
In addition, Cybex’s 770 series Arc Trainers include Muscle MapTM, which displays the intensity of the exercise for individual muscle groups based on the user’s selection of stride rate, resistance and incline.
What the clients say “We install Arc Trainers in many of our gyms, be it corporate sites or education facilities, and the feedback from each one is always very positive,” confirms Chris Koffman, business development director for Nuffield Health.
“The Arc is a unique, innovative piece of equipment that members love and its proven benefits versus a traditional elliptical or cross trainer makes it a staple piece for our gyms.”
London’s Reebok Club, one of Cybex’s largest sites in the capital, has 12 Arc Trainers installed and members and staff alike are big fans: “Instructors and trainers instantly recognise the benefits of its Arc motion and we are seeing users achieve better results thanks to its wide range of training intensities and comfort when in use, which encourages members to train harder for longer,” explains general manager Ben Lewis.
Rob Thurston, Cybex UK commercial director, concludes: “The Arc Trainer offers gyms something that no other fitness equipment manufacturer can; the science and research behind it proves its effectiveness as a tool for not only training for cardio and weight loss, but strength, power and endurance, too.”
Find out more about the science behind the Arc Trainer by visiting www.cybexintl.com to access an archive of research papers.
 Turner, M.J.,Williams,A.B.,Williford,A.L. & Cordova, M.L. (2010) A comparison of physiologic and physical discomfort responses between exercise modalities. Exercise Physiology Research Laboratory,The University of North Carolina at Charlotte, USA.