Over the last few years the popularity of vibration-training has increasingly grown with the development of machines such as PowerPlate (TM) and Vibrogym (TM), and with the recent introduction of personal or 'domestic user' models, the potential for greater training benefits such as strength and power is now being welcomed into our own homes.
From the current commercially available machines a basic vibration platform can cost as little as £100 while the so-called professional editions will set you back as much as £9000. Generally, much of the differences in cost are accountable to the brand name and design. The type of material used and the quality of construction are undoubtedly important factors for machine performance and durability, however aspects such as choice of colour and sleek design are factors that are unlikely to benefit neither your training results nor your bank balance.
When it comes to choosing a vibration platform it is useful to consider the following factors:
The operational parameters -
Apart from the type and duration of exercise performed, the intensity of vibration-training depends on the frequency of vibration (the number of oscillations per second, measured in Hertz, Hz) and the amplitude of the oscillatory wave (mm, cm). The higher these characteristics are the greater the mechanical vibration stimulus.
The frequency range of vibration platforms differ with each model. Collectively, the operating range of commercially available machines is around 15Hz to 60Hz. It is typical however, that machines only operate within a limited frequency range; some between 15-30Hz, others between 30-50Hz, and the majority at and around 35Hz ±10Hz, and at specific step increments. Commonly, the amplitude of vibration is a factor that can also be user-determined. Platform vibration amplitude ranges from around 0.5mm to 12mm (peak to peak displacement) depending on the specific machine. When buying a machine it is important to ensure it is capable of operating at the desired vibration intensities.
Most research has centred on 25- 40Hz, but the optimal frequencies for specific training are yet to be determined. While positive effects of WBV have been found at and around 30Hz, there has been little investigation into lower frequency vibration and whether these provide any benefit. Research activity from our department (Mileva et al., 2006) showed that a frequency as low at 10Hz for segmental vibration aided performance during resistance exercise. For whole-body vibration training however, to prevent hitting the resonant frequencies of internal body organs it is advisable that frequencies lower than 20Hz are avoided (Mester et al., 1999)
The platform dimensions -
Vibration platforms come in a range of sizes. Although machine dimensions are important from a convenience perspective, when choosing a machine it is important to check that the platform area is large enough for performing the type of exercise you require. Performing a deep two-leg squat on a 16 by 12inch platform (as for some low-cost machines) is an exercise feat in itself!
The type of vibration -
Most commercially available machines such as the PowerPlate (TM) and Vibrogym (TM) deliver vertical vibrations and as such the platform moves up and down. However, machines are available that deliver rotational vibration based on a pivot-system platform. As would be expected, there is some evidence to suggest that muscular responses to rotational vibration and vertical vibration differ (Abercromby et al., 2007) although both types of vibration have been shown to have beneficial effects for training (see for example Cochrane and Stannard, 2005 and Delecluse et al., 2003).
User operation -
Some machines come with pre-programmed training regimes with limited flexibility for the user to set their own training programme. If personalisation is required then a machine that allows the user to select parameters such as exercise and rest duration, and number of exercise sets (in addition to the intensity of vibration) should be chosen. Some machines have a limited duration of vibration exposure, so if longer bouts of continuous vibration training are required then the machine capabilities again need to be checked. The majority of vibration-training studies to date have involved less then 10-minutes of continuous vibration training, with many using protocols consisting of approximately 5 sets of 60secs with ~1min rest intervals.
Medical Device Directive certification -
There are a couple of vibration machines on the current market that have Medical CE Approval. To obtain such certification for a device a company needs to provide proof relating to:
-Safety and electrical compliance
-Risk Management and analysis
-Clear clinical Indications and claims
-Clinical proof of these indications
Although this certificate is not direct evidence for validating a machine, it is worth considering in order to know it is of sound operational function.
The Extras -
There are many extras that come along with the more costly platforms such as virtual trainer software, connections for peripheral equipment, and even platforms with inbuilt games consoles. If features such as these are not a necessity then there is very little sense in paying extra for machines that offer them.
Hopefully this short-guide to vibration platform basics has provided enough information for you to choose your machine. Whatever your needs, there is likely to be a machine out on the market that suits you. Good luck!
