Does whole-body vibration training affect arterial stiffness, cognitive ability, and quality of life in chronic stroke? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sport and Exercise in Exercise Prescription and Training at Massey University, Manawatū, New Zealand

Abstract

Background: Stroke is a type of cardiovascular disease, which has the third highest mortality rate in New Zealand. Risk factors of stroke have major consequences on the structure and function of blood vessels and their interaction with circulating blood; altering vascular structure through encouraging atherosclerosis and stiffening of arteries and by inducing thickening, narrowing, and tortuosity of capillaries and arterioles. Additionally, research has reported that the most significant effect of a stroke for a survivor is a decline in health-related quality of life (HRQOL). Studies state that stroke is associated with increased arterial stiffness, and even once established, arterial stiffness can be diminished by a programme of physical activity. Whole-body vibration (WBV) is a safe, easy to use, and time effective exercise intervention that has demonstrated significant improvements in arterial stiffness in healthy men and older sedentary adults. Therefore, it is worthwhile to explore the possibility of WBV as a valuable intervention in chronic stroke. Purpose: To investigate whether 4 weeks of WBV would significantly reduce indices of arterial stiffness, and improve cognition and quality of life in chronic stroke. Methods: Six participants with chronic stroke volunteered for this study. This was a cross-over design, where participants were exposed to WBV training for 4 weeks (3 times a week) on a commercialised Galileo vibration machine with an oscillating platform. WBV parameters were progressed throughout the 4 week intervention (5-7 sets of 60 sec bouts with 60 sec rest, 22-26 Hz, 2.1-6.5 mm, static squatting), and a 2 week washout period was prescribed between WBV and control (usual day-to-day living for four weeks) interventions. Arterial stiffness measurements (carotid arterial stiffness, PWV, PWA), cognition (ACE-III), and quality of life (SF-36), were conducted prior to each intervention and after the completion of each intervention. Additionally, rate of perceived exertion (Borg 15-point scale) was also recorded following every WBV session. Results: No significant improvements were shown for central BPs, HR, or central AIx@75. Additionally, no significant improvements were seen in PWV between WBV and control. There was not significant interaction, or main effects for carotid arterial stiffness (ß), DC or CC. However, carotid arterial stiffness did display a decrease over time for WBV, where arterial stiffness increased for control over time, but these measurements and their interaction effect were not found to be significant (p=0.166). No significant interaction or main effects were found for quality of life (SF-36) or cognitive ability (ACE-III). Finally, there was no significance of RPE over the 4 weeks. Conclusions: Limited studies have investigated the effects of multiple sessions of WBV (short-term training) in stroke, with no study examining the effects of WBV on arterial stiffness, QOL or cognition. The present study found no significant improvements in indices of arterial stiffness, cognitive ability, or QOL. However, this was the first study to investigate the effects of WBV on these variables in chronic stroke; therefore further research with larger sample sizes are needed to investigate the aims of this study further.