Immediate effects of 2 different whole-body vibration frequencies on muscle peak torque and stiffness

Parco M. Siu, Bjorn T. Tam, Daniel H. Chow, Jing Yi Guo, Yan Ping Huang, Yongping Zheng, Stephen H. Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

19 Citations (Scopus)

Abstract

Objective To examine the immediate effects of 2 vibration protocols with different vibration frequencies that yielded the same maximum acceleration (106.75ms-2) on muscle peak torque and stiffness of knee extensor and flexor. Design Randomized crossover study with repeated measures. Setting Laboratory setting. Participants Recreationally active male adults (N=10). Intervention Participants performed 10 bouts of 60-second static half squats intermitted with a 60-second rest period between bouts on a platform with no vibration (control) and a vibration frequency of 26Hz or 40Hz. Main Outcome Measures Concentric and eccentric peak torques of knee extensor and flexor were examined within 5 minutes before and after vibration by isokinetic test. Young's modulus as an index of tissue stiffness was determined at quadriceps and hamstring pre- and postvibration by using an ultrasound indentation method. Results The 2-way repeated-measures analysis of variance indicated a significant interaction effect between vibration and vibration frequency for knee extensor concentric peak torque (P=.003). The vibration-induced changes of knee extensor concentric peak torque in vibration frequency of 26Hz (14.5Nm) and 40Hz (12.0Nm) were found to be significantly greater than that in controls (-29.4Nm) (P<.05). The change in eccentric peak torque of knee flexor after vibration tended to be greater in 26Hz of vibration frequency when compared with controls (26Hz of vibration frequency vs controls: 13.9±7.1 vs -11.4±5.3Nm, P=.08). No statistically significant differences were obtained in tissue stiffness in the quadriceps and hamstring with any of the conditions. Conclusions Our data suggest that whole-body vibration at a frequency of 26Hz and 40Hz preclude the decline in concentric peak torque of knee extensor observed after 10 bouts of 60 seconds of static half squats. A change in muscle mechanical stiffness property as induced by whole-body vibration is not supported by our data.
Original languageEnglish
Pages (from-to)1608-1615
Number of pages8
JournalArchives of Physical Medicine and Rehabilitation
Volume91
Issue number10
DOIs
Publication statusPublished - 1 Jan 2010

Keywords

  • Muscle strength
  • Muscle, skeletal
  • Rehabilitation

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation

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