title: Effect of four-month vertical whole body vibration on performance and balance.
abstract: OBJECTIVE
  This randomized controlled study was designed to investigate the effects of a 4-month whole body vibration-intervention on muscle performance and body balance in young, healthy, nonathletic adults.
  
  
  METHODS
  Fifty-six volunteers (21 men and 35 women, aged 19-38 yr) were randomized to either the vibration group or control group. The vibration-intervention consisted of a 4-month whole body vibration training (4 min.d(-1), 3-5 times a week) employed by standing on a vertically vibrating platform. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway on a stability platform) were performed initially and at 2 and 4 months.
  
  
  RESULTS
  Four-month vibration intervention induced an 8.5% (95% CI, 3.7-13.5%, P=0.001) net improvement in the jump height. Lower-limb extension strength increased after the 2-month vibration-intervention resulting in a 3.7% (95% CI, 0.3-7.2%, P=0.034) net benefit for the vibration. This benefit, however, diminished by the end of the 4-month intervention. In the grip strength, shuttle run, or balance tests, the vibration-intervention showed no effect.
  
  
  CONCLUSIONS
  The 4-month whole body vibration-intervention enhanced jumping power in young adults, suggesting neuromuscular adaptation to the vibration stimulus. On the other hand, the vibration-intervention showed no effect on dynamic or static balance of the subjects. Future studies should focus on comparing the performance-enhancing effects of a whole body vibration to those of conventional resistance training and, as a broader objective, on investigating the possible effects of vibration on structure and strength of bones, and perhaps, incidence of falls of elderly people.
authors.affiliation: Bone Research Group, UKK Institute, Kaupinpuistonkatu 1, FIN-33500 Tampere, Finland. losato@uta.fi
authors.forename: Saila
authors.initials: S
authors.lastname: Torvinen
authors.forename: Pekka
authors.initials: P
authors.lastname: Kannus
authors.forename: Harri
authors.initials: H
authors.lastname: Sievänen
authors.forename: Tero A H
authors.initials: TA
authors.lastname: Järvinen
authors.forename: Matti
authors.initials: M
authors.lastname: Pasanen
authors.forename: Saija
authors.initials: S
authors.lastname: Kontulainen
authors.forename: Teppo L N
authors.initials: TL
authors.lastname: Järvinen
authors.forename: Markku
authors.initials: M
authors.lastname: Järvinen
authors.forename: Pekka
authors.initials: P
authors.lastname: Oja
authors.forename: Ilkka
authors.initials: I
authors.lastname: Vuori
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D014732:Vibration