title: Deviations of frequency and the mode of vibration of commercially available whole-body vibration training devices.
abstract: OBJECTIVE
  Research in the field of whole body vibration (WBV) training and the use of it in practice might be hindered by the fact that WBV training devices generate and transmit frequencies and/or modes of vibration which are different to preset adjustments. This research project shall clarify how exact WBV devices apply the by manufacturer information promised preset frequency and mode of vibration.
  
  
  METHODS
  Nine professional devices for WBV training were tested by means of a tri-axial accelerometer. The accelerations of each device were recorded under different settings with a tri-axial accelerometer. Beneath the measurement of different combinations of preset frequency and amplitude the repeatability across 3 successive measurements with the same preset conditions and one measurement under loaded condition were carried out.
  
  
  RESULTS
  With 3 exceptions (both Board 3000 & srt medical PRO) we did not find noteworthy divergences between preset and actual applied frequencies. In these 3 devices we found divergences near -25%. Loading the devices did not affect the applied frequency or mode of vibration. There were no important divergences measurable for the applied frequency and mode of vibration regarding repeatability.
  
  
  CONCLUSIONS
  The results of our measurements cannot be generalized as we only measured one respectively at most two devices of one model in terms of a random sample. Based on these results we strongly recommend that user in practice and research should analyse their WBV training devices regarding applied frequency and mode of vibration.
authors.affiliation: Institute of Sports Medicine, Hannover Medical School, Hannover, Germany - kaeding.tobias@mh-hannover.de.
authors.forename: T S
authors.initials: TS
authors.lastname: Kaeding
mesh_terms: D061725:Accelerometry; D006801:Humans; D013178:Sports Medicine / Q000295:instrumentation*; D014732:Vibration