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585

REVIEW

Whole body vibration exercise: are vibrations good for you?
M Cardinale, J Wakeling
............................................................................................................................... Br J Sports Med 2005;39:585–589. doi: 10.1136/bjsm.2005.016857

Whole body vibration has been recently proposed as an exercise intervention because of its potentialfor increasing force generating capacity in the lower limbs. Its recent popularity is due to the combined effects on the neuromuscular and neuroendocrine systems. Preliminary results seem to recommend vibration exercise as a therapeutic approach for sarcopenia and possibly osteoporosis. This review analyses state of the art whole body vibration exercise techniques, suggesting reasons why vibrationmay be an effective stimulus for human muscles and providing the rationale for future studies.
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fitness and rehabilitation centres are using vibration in their exercise programmes, but current knowledge on appropriate safe and effective exercise protocols is very limited, and claims made by companies and pseudo-expertscan be misleading. The purpose of this review is to analyse the potential mechanisms by which muscles respond to vibration and to summarise current knowledge of the effects of vibration on human strength and power performance.

IS VIBRATION A NATURAL STIMULUS?
During all sporting activities our bodies interact with the external environment and experience externally applied forces. These forcesinduce vibrations and oscillations within the tissues of the body. Tissue vibrations can be induced from impact related events where either a part of the body or sporting equipment in contact with the body collides with an object. Examples of this are the impact shocks that are experienced through the leg when the heel strikes the ground during each running stride or the impact shock that occurswhen a racquet is used to hit a ball. The initial impact causes vibrations within the soft tissues, after which the tissues continue to oscillate as a free vibration—that is, vibrating at their natural frequency, with the amplitude of these vibrations decaying because of damping within the tissues. Tissue vibrations can also be induced when the body experiences more continuous forms of vibration,such as may occur through the legs during skiing across a groomed slope or through the arms during bike riding. A continuously oscillating input force drives the soft tissue vibrations to be at the same frequency as the input force, but the amplitude of the vibrations will be greatest if the natural frequency of the tissues is close to that of the input force (resonance); however, the amplitude ofthese larger amplitude vibrations can be reduced by damping from the tissues. Therefore we can expect to experience soft tissue vibrations in all sporting activities, and the amplitude and frequency of these vibrations is partly determined by the natural frequency and damping characteristics of the tissues. The body relies on a range of structures and mechanisms to regulate the transmission ofimpact shocks and vibrations through the body including: bone, cartilage, synovial fluids, soft tissues, joint kinematics, and muscular activity. Changes in joint kinematics and muscle activity
Abbreviations: WBV, whole body vibration; WBVT, whole body vibration training

See end of article for authors’ affiliations ....................... Correspondence to: Dr Cardinale, College of Life Sciencesand Medicine, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK; m.cardinale@abdn.ac.uk Accepted 25 April 2005 .......................

ibration is a mechanical stimulus characterised by an oscillatory motion. The biomechanical variables that determine its intensity are the frequency and amplitude. The extent of the oscillatory motion determines the amplitude (peak to peak displacement,...
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