title: Chronic effects of whole-body vibration on jumping performance and body balance using different frequencies and amplitudes with identical acceleration load.
abstract: Previous studies on vibration training have all been based on protocols at different combinations of frequencies and amplitudes without controlling the loading intensity.
  
  
  OBJECTIVE
  This study investigated the effect of an 8-week vibration training program, under identical acceleration loads with various frequencies and amplitudes, on jumping performance, muscle activation and body balance.
  
  
  METHODS
  Fifty young adults were randomly assigned to an high-frequency (32 Hz, 1mm, and 4 g), low-frequency (18 Hz, 3 mm, and 4 g), or a control group. The high-frequency and low-frequency groups underwent 60 s of squats exercise on the specific vibration platform three times a week, whereas the control group was trained without vibration.
  
  
  METHODS
  A force platform was used to measure the center of pressure of a static single leg stance, and the heights and impulse of two consecutive countermovement jumps before and after intervention. The activation of the rectus femoris and biceps femoris were also measured synchronously by surface electromyography.
  
  
  RESULTS
  The heights and impulse of both the first and second countermovement jumps were significantly increased and the area of center of pressure was significantly decreased after training in both the high-frequency and low-frequency groups (P<.05). Consequently, activation of the rectus femoris during the first countermovement jump was significantly lower than the pre-training value in the HF group but increased in the low-frequency group after training (P<.05).
  
  
  CONCLUSIONS
  An 8-week identical acceleration vibration training regimen with various frequencies and amplitudes can significantly improve jumping performance and body balance, but the specific neuromuscular adaptation is possibly induced by different training settings.
authors.affiliation: Department of Physical Education, National Taiwan Normal University, Taipei, Taiwan.
authors.forename: Chia-Hsiang
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Graduate Institute of Sports Equipment Technology, Taipei Physical Education College, Taipei, Taiwan.
authors.forename: Chiang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Chinese Martial Arts, Chinese Culture University, Taipei, Taiwan.
authors.forename: Long-Ren
authors.initials: LR
authors.lastname: Chuang
authors.affiliation: Graduate Institute of Sports Equipment Technology, Taipei Physical Education College, Taipei, Taiwan.
authors.forename: Pao-Hung
authors.initials: PH
authors.lastname: Chung
authors.affiliation: Graduate Institute of Sports & Exercise Science, National Taiwan Normal University, Taipei, Taiwan. Electronic address: tyshiang@gmail.com.
authors.forename: Tzyy-Yuang
authors.initials: TY
authors.lastname: Shiang
mesh_terms: D054874:Athletic Performance; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D064797:Physical Conditioning, Human; D004856:Postural Balance; D014732:Vibration; D055815:Young Adult
keywords: Countermovement jump; Static single leg stance; Whole body vibration training