Vertical Whole Body Vibration (WBV) Types

This section describes the different types of vertical whole body vibration machines. Although all these machines have plates that move in the vertical direction (or “mostly” vertical), the technology used to create this motion varies significantly. Consequently, the range of settings and especially the subjective quality of the vibration varies significantly.

 
Linear Motor
Complementary Eccentric Weight
Crank

 

Elliptical Vibration

Oscillating Vibration

Elliptical Vibration

Drive System

A linear motor (or voice coil actuator), usually located directly beneath the plate. This type of motion control system is used in industry and aviation to precisely control the position of lenses, control surfaces and other mechanics that require fast and accurate positioning.

The vibration producing mechanism is a pair of complementary rotary motors. Each has an eccentric weight attached to the end of its shaft that causes it to vibrate when it spins. The motors spin in opposite directions and are synchronized so that sideways forces cancel out, resulting in a “mostly” vertical movement.

Rotary motor with crankshaft connected to the plate that drives the plate up and down as it rotates.

Construction

The vibrating plate is directly coupled to the shaft of the linear motor that slides in and out to move the plate in an oscillating motion. Springs are usually used to support the plate so that the motor only contributes the vibrating motion. Sometimes more than one linear motor is used.

The motors are attached directly to the underside of the plate. The plate rests on springs or rubber supports.

The motor and crank mechanism is usually located under the plate. Unlike other vertical types, no springs are needed to support the plate.

Best feature

Gentle, springy feel.

Reliable and compact.

Compact

Biggest problem

Intrinsically expensive to manufacture.

Inability to control force of vibration.

No “give” in crank mechanism results in harsh ride.

Frequency

2Hz to 80Hz

20Hz to 50Hz, although the frequency affects the force, so the useful range is narrower.

5Hz to 50Hz, although since the amplitude is fixed, the usable range is usually limited to 25..35Hz. (Below 20Hz is ineffectual and above 40Hz is unbearable.)

Control of vibration force

Continuously adjustable from 0 to 100% in 1% (or smaller) increments, independent of frequency.

The force cannot be adjusted. The force does however change as a result of changing the frequency (the speed of the motor). This is because the motors produce more force the faster that they spin.

The force cannot be adjusted, although force does change with frequency, as with the complementary motor design.

Primary use

Therapeutic

Exercise

Exercise

Range of exercise

User can stand erect and therefore vibration is transferred to all tissue, from head to toe. True whole body vibration. User can also sit comfortably on the vibrating plate.

With almost all machines of this type it is necessary to bend the knees in order to shield the upper body from the intense vibrations. Therefore this cannot be considered whole body vibration, but rather half-body vibration. Vibration in the upper body will only occur by adopting a floor position with hands on the plate (and elbows bent). Even with this adaptation, there is little vibration carried to the internal organs.

The user can stand upright or sit as long as the frequency is set such that the vibration is comfortable. While this could be regarded as true whole body vibration, it is only possible to stand upright (without significant discomfort) for a very narrow range of frequency (a few Hz). This narrow frequency range means a limited range of professional applications.

Quality of user experience

Smooth and gentle. A linear motor does not have the inertia of a rotary motor (used on all other types of vibration platform). The plate has a "springy" feel, and gives when offered resistance.

Feels rough and jarring. This is partly due to the inability to control the vibration force, and also due to the momentum of the spinning motor under the plate.

Vibration is smooth, but not gentle. The crank mechanism ensures that the plate will move in a prescribed motion, no matter what resistance it is offered. If you fight it, it will win. This results in a subjective experience that is comfortable at lower frequencies, but becomes harsh at higher frequency.

Motor noise

Low noise, due to the simplicity of the mechanism.

Medium noise.

Medium to high. Excessive noise can result from the linkage mechanism, especially at higher frequencies.

Mechanical reliability

Very reliable due to the simplicity of the mechanism and few moving parts. Direct coupling between the linear motor and the plate results in a mechanism that is free of rattle or other side-effects that can reduce reliability.

High reliability due to few moving parts, assuming that the motors are selected to support use in this manner.

Generally less reliable because of the number of moving parts and bearings that are exposed to alternating forces.

Example products

  • TheraVibe™
  • TurboSonic
  • Fitvibe
  • Wave
  • Pineapple
  • Bodygreen

Frequency: A wide frequency range means more therapeutic uses and a wider range of benefits. For example, improving range of motion and mobility is more effective in the 3..6Hz range. Similarly, frequencies above 70Hz show promise in weight management.

Control of vibration force: This is the vibration force experience while standing on the vibration plate. Often referred to in relation to the "gravitational force". For therapeutic devices it is essential that the vibration force is adjustable. The ideal range is from a level low enough to be barely perceptible to a maximum that results in an equivalent of gravitational force.

Range of exercise: This determines the range of extent of benefits and is therefore just as important (if not more so) than the ability to independently control frequency and amplitude.

Quality of vibration as experienced by the user: We believe that in addition to outcomes of better health the experience of whole body vibration should be enjoyable. We also believe that the body has sufficient intelligence to know what is beneficial and hence we consider the subjective quality of the vibration to be an important component of the value of a vibration machine.

Motor Noise: Low noise is desirable for most commercial settings. This is especially true in many day-spa settings where the environment is soothing, peaceful and calm.

Mechanical Reliability: This is critical for any professional environment where the machine is generating revenues and where people are booking the use of the machine. (This section describes the potential reliability, since reliability also depends on the quality of manufacture.)