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Whole body vibration (WBV) is a generic term used where any vibration of any frequency is transferred to the human body. Vibration training on the other hand is a discipline where varying frequencies/amplitudes/forces will be transferred into separate body parts using precise joint angles for any limited time (approximately 1 minute sets). This is done to create a purely eccentric muscle reaction and enable anaerobic activity (burning energy without oxygen – the opposite of cardio). It should not be confused with uncontrolled vibrations in occupational settings such as truck driving or hand tool operating. It is important to point out that the first systems were especially designed to be a form of resistance training.
WBV can be split into 2 simple categories; WBV Physiotherapy and WBV Training. WBV Physiotherapy includes stretches and massages in light contact with the machine or with minimal body weight behind the position. These positions should be zero effort (burning no energy). The most widely promoted WBV Physiotherapy position is standing upright, lock-legged on a pivotal or low energy lineal machine (this is often unethically sold as a weight-loss position).
WBV Training is always done through a series usually with a minimum of 5 compound poses including half-squat, half-push up, wide stance squat, tricep dip and the plank hold. These static positions are usually held for a maximum of 1 minute and are designed to burn the maximum amount of energy in the shortest amount of time while causing no joint damage. As this is a new science and clear scientific definitions are yet to be agreed upon, the classic perceived exertion test should be the best indication of each specific position's intended purpose. In WBV Training terms this means if a position is being held correctly, muscle fatigue in the targeted body part should be reached within 1 minute (If the position is still able to be continued without exertion, it is therapy).
Whole body vibration may refer to vibration training, also known as vibration therapy, biomechanical stimulation (BMS), and biomechanical oscillation (BMO), a training method employing low amplitude, low frequency mechanical stimulation to exercise musculoskeletal structures for the improvement of muscle strength, power, and flexibility. Vibration training has been advocated as a therapeutic method in the treatment of osteoporosis, sarcopenia, and metabolic syndrome, and is used in the fitness industry, physical therapy, rehabilitation, professional sports, and beauty and wellness applications.
Occupational WBV exposure, especially when chronic, is suspected to cause adverse health effects such as fatigue, lower back pain, vision problems, interference with or irritation to the lungs, abdomen, or bladder, and adverse effects to the digestive, genital/urinary, and female reproductive systems. Mandatory standards for regulation and monitoring of worker exposure to WBV exist in Europe; in the U.S., there are reference standards but no specific regulations.
There are two categories of machinery – Pivotal and Lineal. The best way to describe these actions are as follows; Pivotal is like jumping side-to-side from one foot to the other; Lineal is like jumping up and down or doing push ups in one spot. Pivotal primarily works on the speed of the machine, looking at peak performance of approximately 27 Hz. Lineal works on a Mass x Acceleration x Frequency principle that could be best explained by the difference of catching a light ball to that of a heavy ball, and every ratio in between.
A pivotal machine running on a low frequency (12 Hz and under) would be mainly used for physiotherapy applications and some strength and conditioning. Above this frequency it enters the area of exercise discipline and comes with some associated risks. For example, high speed with incorrect positioning could cause tissue damage.
Whereas with Lineal machines the frequency is not so important, e.g. a lighter frame plastic or fiberglass machine running at 50 Hz would be mainly considered physiotherapy with some strength and conditioning applications. Some flexibility in positions on these lighter machines is allowed and should not cause any associated tissue damage.
Vibration training as a discipline is known as “High Energy Lineal” and this signifies the use of a heavy vibration unit with limited amplitude (0.7mm-6mm) performed most effectively and safely by static positions. Static positions are commonly mistaken for isometric poses.
In the 1880s and 1890s, John Harvey Kellogg was utilizing vibrating chairs, platforms and bars at his Battle Creek, Michigan sanitarium. These methods were part of his "wellness" strategies for inpatient and outpatient populations.
The immediate predecessor of modern vibration training is Rhythmic Neuromuscular Stimulation (RNS). In former East Germany Biermann was experimenting with the use of cyclic massage and its effects on trunk flexion back in the sixties (Biermann, 1960).
In that same era the Russian scientist Nazarov translated these findings into practical uses for athletes. He observed a substantial increase in flexibility and strength after the application of vibrations in the athletes he studied (Kunnemeyer & Smidtbleicher, 1997). The Russians also carried out experiments with "Biomechanical Stimulation" for the benefit of their athletes as well as in their space program. Unlike WBV devices on which the user stands, Biomechanical Stimulation uses vibration stimulation directly on muscles or tendons.
Due to the lack of gravity in space, astronauts and cosmonauts exhibited muscle atrophy (muscle impairment) and bone loss, which forces them to return to earth rather quickly. To prevent muscle and bone loss on long term mission the European Space Agency as well as the DLR are experimenting with various types of vibration systems as a supplement to other fitness training.
Vibration training has often been referred to as used by astronauts and cosmonauts but this is not strictly true. To date, space agencies have only looked at vibration therapy. A machine capable of being classed as a vibration training machine has never been installed on the international space station due to its shear weight and most likely will never be feasible. The first test for vibration therapy for astronauts was in fact done on turkeys. The engineering issues came into play when they tried to upgrade the machine to take the weight of a human being. Once the vibration intensity grew strong enough to lift over 40 kg, fractures appeared in the steel. Unfortunately a number of marketers hijacked the turkey studies and applied them in advertising directly to humans.
NASA, since 1961, has been doing tests at adding light vibrations to pre-existing exercise equipment’s such as the Treadmill Vibration Isolation System (TVIS) and the Cycle Ergometer Vibration Isolation System (CEVIS). Any company referencing NASA directly in its marketing campaigns is highly misleading and has no relevance to the discipline of vibration training, but aligns instead with vibration therapy.
Vibrating platforms fall into different, distinct categories. The type of platform used is a moderator of the effect and result of the training or therapy performed (Marin PJ, Rhea MR, 2010). Main categories of machine types are: 1. High Energy Lineal, found mostly in commercial vibration training studios and gyms. The vibration direction is lineal/upward eliciting a strong stretch-reflex contraction in muscle fibres targeted by the positions of training program. 2. Premium Speed Pivotal, (teeter-totter movement) used for physiotherapy work at lower speeds and exercise workouts at “premium” speed, up to 30 Hz. Both commercial and home units are available. 3. Medium Energy Lineal, the majority of lineal platforms produced. These are usually made of plastic; some have 3-D vibration which is low quality. They give slower and less consistent results. 4. Low Speed Pivotal units. These can give “therapy” benefits. Other machine types are low Energy/Low amplitude lineal and Low energy/High amplitude lineal with varying uses from osteoporosis prevention, therapy for improved blood circulation and flexibility and limited fitness training.
In order to elicit a stretch reflex in the muscles, the major contributing factor to the training results that can be achieved with vibrating platforms, the up-down movement is the most important. The platform is vibrated upwards to work directly against gravity and therefore is called "hyper-gravity". High Energy Lineal Machines can overload the muscles up to 6 times(6G)in the upward phase; meaning the person on the platform is weight training using their own body mass.
The training frequency (Hz) is another of the important factors involved. The human body is designed to absorb vertical vibrations better due to the effects of gravity; however, many machines vibrate in more than one direction: sideways (x), front and back (y) and up and down (z). The z-axis has the largest amplitude and is the most defining component in generating and inducing muscle contractions.
Systems with side alternation usually offer a larger amplitude of oscillation and a frequency range of about 5 Hz to 35 Hz. Linear/upright systems offer lower amplitudes but higher frequencies in the range of 20 Hz to 50 Hz. Despite the larger amplitudes of side-alternating systems, the vibration (acceleration) transmitted to the head is significantly smaller than in non side-alternating systems (Abercromby et al. 2007). This difference can be a determining factor when choosing a platform for therapy versus training effects.
Mechanical stimulation generates acceleration forces acting on the body. These forces cause the muscles to lengthen, and this signal is received by the muscle spindle, a small organ in the muscle. This spindle transmits the signal through the central nervous system to the muscles involved (Abercromby et al. 2007, Burkhardt 2006).
Due to this subconscious contraction of the muscles, many more muscle fibers are used than in a conscious, voluntary movement (Issurin & Tenenbaum 1999). This is also obvious from the heightened EMG activity (Bosco et al. 1999, Delecluse et al. 2003).
If a platform has sufficient mass and amplitude running under 50 Hz, the response elicits a pure eccentric contraction. This is the catching/landing/lowering phase of an action as opposed to the throwing/jumping/pushing phase (concentric).
Vibration training is purely eccentric and anaerobic in traction which can take the targeted muscles to complete fatigue over a short period of time (approximately 60 seconds). The reason for the short during of the sets is that the muscle can respond in an eccentric fashion down to approximately 40 m/s (40 contractions per second), as opposed to concentric contractions that are much slower and less powerful. The reason the eccentric phase is sought after for physiotherapy or training purposes is heavy eccentric loading taking the muscle to complete fatigue does not induce the same amount of tissue damage or inflammation markers as concentric phases do, but exert the same amount of force and energy from the body.
So to recap; vibration training is neither concentric nor aerobic.
More motor units (and the correlating muscle fibers) are activated under the influence of vibration than in normal, conscious muscle contractions. Due to this, muscles are incited more efficiently (Paradisis & Zacharogiannis 2007; Lamont et al. 2006; Cormie et al. 2006; Bosco et al. 1999, 2000; Rittweger 2001, 2002; Abercromby et al. 2005; Amonette et al. 2005). The immediate effect of WBV is therefore that the muscles can be used quickly and efficiently, rendering them capable of producing more force. However, this process will only be effective if the stimulus is not too intense and does not last too long, because otherwise performance will diminish due to fatigue.
Another immediate effect of WBV is an improvement of circulation. The rapid contraction and relaxation of the muscles at 20 to 50 times per second basically works as a pump on the blood vessels and lymphatic vessels, increasing the speed of the blood flow through the body (Kerschan-Schindl et al. 2001; Lohman et al. 2007). Subjects often experience this as a tingling, prickling, warm sensation in the skin. Both Stewart (2005) and Oliveri (1989) describe the appearance of vasodilatation (widening of the blood vessels) as a result of vibration.
In order to have any effect on the body in the long term it is vital that the body systems experience fatigue or some sort of light stress. As in other kinds of training, when the body is overloaded repeatedly and regularly, the principle of supercompensation applies. This principle is the cause of the body adapting to loading. In other words: performance will increase.
This effect has been proven several times in scientific research for both young and elderly subjects (Roelants et al. 2004, Delecluse et al. 2003, Verschueren et al. 2004, Paradisis et al. 2007). The only placebo-controlled study to date (Delecluse et al. 2003) concluded "specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes". Therefore there is no clear indication that the vibrations actually do have added value when performing static exercises.
From research into the structural effects of vibration training it can be deduced that the increased strength resulting from WBV training can definitely be compared to the results that can be attained with conventional methods of training. But there are indications that better results may be achieved with WBV in the area of explosive power (Delecluse et al. 2003).
Another important difference between conventional training methods and WBV is that there is only a minimum of loading. No additional weights are necessary, which ensures that there is very little loading to passive structures such as bones, ligaments and joints. That is why WBV is highly suited to people that are difficult to train due to old age, illness, disorders, weight or injury. On the other hand, it is also highly suitable for professional athletes who want to stimulate and strengthen their muscles without overloading joints and the rest of the physical system (Cochrane et al. 2005; Mahieu et al. 2006).
Other than its influence on the muscles, WBV can also have a positive effect on bone mineral density. Vibrations cause compression and remodeling of the bone tissue Mechanostat, activating the osteoblasts (bone building cells), while reducing the activity of the osteoclasts (cells that break bone down). Repeated stimulation of this system, combined with the increased pull on the bones by the muscles, will increase bone mineral density over time. It is also likely that improved circulation and the related bone perfusion due to a better supply of nutrients, which are also more able to penetrate the bone tissue, are contributing factors (Verschueren 2004, Jordan 2005, Olof Johnell & John Eisman, 2004, Rubin et al. 2004).
Furthermore the Berlin Bedrest Study (BBR) proved that 10 minutes of vibration training 6 times a week prevented muscle and bone loss in total bedrest over 55 days (Rittweger et al. 2004, Felsenberg et al. 2004, Bleeker et al. 2005, Blottner et al. 2006).
In preventing falls and the bone fractures that often result from them, enhancing bone mineral density is not the only important issue. Increased muscle power, postural control and balance are also factors worthy of consideration. Studies involving elderly subjects have shown that all of these issues can be improved using whole body vibration (Roelants et al. 2004, Bautmans et al. 2005, Bogaerts et al. 2007, Kawanabe et al. 2007).
Although much research has covered these areas (bone mineral density, circulation etc.), research currently only suggests an effect on weight loss when also reducing caloric intake. It is also not clear that the effects of whole body vibration can give similar results as that of regular exercise. In reality, vibration machines are not a replacement for weight loss and healthy living, and those under this impression are at a risk of neglecting their health. A study by Roelants et al. (2004) found that 24 weeks of whole body vibration did “not reduce weight, total body fat or subcutaneous fat in previously untrained females.”
A study on previous research findings completed in July 2012 found that no causality can be shown between whole-body vibration and abnormal spinal imaging findings.
The discipline of vibration training has been popularly crossed with other disciplines ranging from yoga, Pilates, boxing to plyometrics. Even though this goes against the idea of pure vibration training it seems to limit its effectiveness. It seems to catch the imagination of personal trainers and consumers, which unfortunately has led to either confusion or the outright unethical practice of promoting vibration training as similar to cardiovascular exercise. Indeed a lot of the positions and practices advertised are not recommended by the engineers that built the machines. As with all exercise disciplines, marketing has unfortunately diluted the science.