This technology originally developed to help Astronauts on keeping fit at low gravity could take over on conventional weight machines on fitness centers and this is why.
In the late 1980s, the growing interest in long-term space travel posed the problem of astronaut health. In the absence of gravity, their musculoskeletal system, no longer called upon to support the weight of the trunk, undergoes a marked muscular atrophy (loss of mass and strength) and a decrease in bone mineral density. For this reason, the American (NASA) and European (ESA) Space Agencies have begun to seek a solution to the problem of training astronauts in space.
The solution came from the studies of Per Tesch and Hans Berg, two researchers at the prestigious Karolinska Institutet in Stockholm, which annually awards the Nobel Prize in Medicine and Physiology. Using a flywheel rotated by a belt, Tesch and Berg have created a machine for resistive training that works regardless of the force of gravity. This technology, also known as isoinertial, has been patented with the name YoYo Inertial TechnologyTM for its similarity with the homonymous toy.
In scientific literature YoYoTM devices are also referred to as flywheel exercise devices.
The system works as follows:
- During the concentric phase (CON) of the exercise, the muscle is contracted with the maximum possible force by pulling a belt (or a rope) rolled up on the flywheel axis, rotating it at high speed. The belt is of such length that it can be completely unwound at the end of the movement.
- Due to its inertia, the flywheel continues to rotate by rewinding the belt in the opposite direction, pulling the limb towards itself and starting the next eccentric phase (ECC). After a mild initial resistance, the subject begins to brake by pulling the belt until the flywheel stops completely.
Disclaimer: the above images are courtesy of nhance (http://nhance.se/). These machines are powered by the original YoYo Technology
By starting to pull again, the next repetition begins, and so on for the duration of the exercise. It is possible to vary the inertia by mounting a greater or lesser number of flywheels. The effectiveness of isoinertial technology has been proven by numerous independent laboratory studies and more than 150 publications in international scientific journals.
Its application has been successfully extended to the sports sector, where it is used for training and injury prevention in athletes and elite teams. Since muscle atrophy and bone decalcification are effects that can also be observed in patients forced to immobility due to trauma, disease or age, the use of YoYoTM technology can also be extended to rehabilitation and geriatric medicine.
One of the main differences compared to conventional exercises (weight machines, barbells or dumbbells) is that, while with weights the resistance is constant and equals the set load (isotonic exercise), in YoYoTM devices the resistance is variable and is at all times proportional to the force developed: the greater the force, the greater the acceleration with which the flywheel reacts (isoinertial exercise).
With weights, the exercise ends when the maximum force that you can develop drops, due to fatigue, under the set load. It follows that all repetitions, except the last one, are by definition sub-maximal. Conversely, in a YoYoTM device, each repetition is always carried out at the maximum strength that the athlete is able to produce, even if this decreases with fatigue. It follows that the “dose” of training (work) for a given number of repetitions is higher than with weights. Furthermore, since there is no minimum load threshold, it is possible to continue the exercise until exhaustion.
Due to the constant load, the weight machines also require special cams to compensate for the changes in the lever arm of the muscle along the joint excursion. These cams, designed for “medium” anthropomorphy may not be optimal for athletes with non-standard stature or with deficits at particular joint angles, for example following injuries. Thanks to the variable resistance, YoYoTM devices instead adapt optimally to the force that the athlete is able to develop at each moment and at each joint angle.
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Furthermore, while in a traditional exercise the choice of load is critical in determining the number of repetitions per series, in a YoYoTM device it is possible to use the same inertia for a very wide range of use, both at very low and very intense forces. Unique peculiarity of iso-inertial machines, inertia rather establishes the speed at which the exercise is performed. In other words, each repetition is always maximal, and inertia only determines the speed of execution: the lower the inertia, the greater the acceleration and deceleration of the flywheel, the speed of execution and the consequent “explosiveness” of the athletic gesture .
Lastly, the iso-inertial exercise, being with variable force, is much more similar to the normal functioning of the muscle than a constant force exercise. In sports, for example, the great majority of gestures concern the acceleration and deceleration at high force of an inertial mass (for example a ball or a part of the body itself). A YoYoTM machine recreates the same operating mode, transforming the acceleration of a rotating inertial mass (the flywheel) into a mono- or multi-articular gesture.
Huge Sci Fi Movie Watcher, love and passion for anything digital, Daniele is intrigued by how technology is shaping human being’s everyday life….including our overall fitness and health standards by introducing new aliments to our daily nutrition list namely “nutropics”.