Evaluation of the Impact of Mechanical Vibration on the Adult Skeleton

The potential for exercise to maintain or enhance bone strength during ageing is of increasing interest. Preliminary evidence suggests that whole body vibration (WBV) can enhance muscle strength and maintain bone density in postmenopausal women, and may provide low impact anabolic exercise suitable for use in patients with weakened skeletons. The main aim of this thesis is to evaluate the impact of WBV on the adult human skeleton, putting the impact of WBV in the context of other habitual locomotor activities in order to analyse which WBV settings may hold most osteogenic potential. The potential for a unilateral model of WBV using the Galileo 900 was also assessed. To investigate these aims, transmission of WBV delivered by the Galileo 900, Powerplate Pro 5 and Juvent 1000 platforms was assessed using a motion capture system. Strain at the tibia was recorded using a bone surface bonded strain gauge. The results presented here suggest that WBV is transmitted to the hip and spine on all platforms, however attenuation of the WBV stimulus is observed above the anterior superior iliac spine. The greatest attenuation is observed with the Galileo 900 which has a side alternating motion as opposed to the vertical motion of the Powerplate Pro 5 and Juvent 1000. The greatest accelerations transmitted to the hip and spine are generated by the Powerplate Pro 5, with the Galileo 900 delivering lower accelerations for similar input frequency and amplitudes and the Juvent 1000 delivering 10 fold lower accelerations. The unilateral loading model of WBV appears to be possible as, when a single leg is placed on the platform, transmission of WBV to the contralateral leg is far less than to the leg on the platform. This is also reflected in the strain and strain rates observed when the strain gauged leg is placed on the platform as opposed to off the platform during WBV. Strains and strain rates generated during WBV on the Powerplate Pro 5 and Juvent 1000 are comparable to those generated whilst walking, however on the Galileo 900, strains equivalent to those generated whilst performing high impact activities such as jumping are observed. Strain rates of much greater magnitude than those observed during habitual locomotor activities are also generated on the Galileo 900