The effect of vibration exercise on aspects of muscle physiology and muscular performance : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, Massey University, Palmerston North, New Zealand

Abstract

It has been proposed that the increases in muscle force and power following acute vibration exercise are similar to that of several weeks of conventional resistance or explosive power training. Further, it has been purported that vibration exercise operates via a stretch-reflex response which elicits a small change in muscle length. However, despite its wide use there remain gaps of knowledge on aspects such as physiological effects, mechanism of action, clinical effects, and even details of regimens for particular therapeutic use. Therefore, the aim of this thesis was to investigate the acute effects of vibration exercise on muscle performance and to examine the physiological aspects of its use in the young and older people, and competitive athletes. This thesis reported that acute upper-body vibration enhanced concentric peak power, but it was not significantly greater than concentric (arm-cranking) exercise. When matched for metabolic rate, vibration exercise elevated muscle temperature more quickly than traditional forms of warm-up by cycling or passive heating, but there were no significant differences in the increase in muscle power between the interventions, which suggested that the interventions were temperature dependent. There was no apparent benefit in performing a shallow, fast tempo dynamic squat with vibration because muscle temperature, cardiovascular indices, and metabolic rate were increased by the same amount and rate without vibration. Further, the Jendrassik manoeuvre did not potentiate the metabolic rate in young or older adults when superimposed with vibration exercise and the patellar reflex was not enhanced after vibration exercise, but muscle twitch potentiation was evident. However, low frequency vibration exercise induced a small change in muscle length and increased muscle activation, suggesting that spinal reflexes were involved. In conclusion, vibration exercise with a static squat could be used as a warm-up modality after interval breaks, as it would incur a low metabolic cost and be time efficient. It appears that the increases in muscle performance from vibration exercise are not caused by a neurogenic potentiation because patellar tendon reflex showed no significant augmentation and muscle twitch properties were enhanced. Vibration exercise elicited a small increase in metabolic rate and cardiovascular indices. Given that a main objective of a balanced exercise programme is to increase aerobic capcity it would be unwise to completely substitute conventional aerobic exercise with vibration. However, when conventional aerobic exercise is not possible, for example, in aged, cardiovascular compromised persons, vibration exercise could be implemented at an early stage because it could provide a safe induction of a low level of cardiovascular strain. Vibration exercise has the potential to benefit sport, exercise, and health however, it should be used to compliment other modalities but it should never be used in preference or in isolation to other programmes.