Effect of vibration frequency and angle knee flexion on muscular activity and transmissibility function during static whole body vibration exercise

摘要

Whole body vibrations (WBV) created by the use of vibrating platform exercise were largely studied for their impact on muscular activity, neuromuscular and postural control (Fratini et al. 2009). Lower limb muscle response to vibration depends on static body position, muscle stiffness, amplitude and frequency of the mechanical vibration (Pollock et al. 2010). Nevertheless, the effect of body position and frequency of vibration on electromyography (EMG) signal are still discussed as several previous studies reported muscular activity increase (Fratini et al. 2009; Pollock et al. 2010; Giminiani et al. 2013), whereas recent studies indicate no significant variation in EMG activity (Avelar et al. 2013). These differences could be due to the vibrations parameters, i.e. amplitude (1-5 mm) and frequency (5-55 Hz), the degree of knee flexion (5-90°) used and the muscle studied. Moreover, most of the time, these studies used closed chain configuration since subjects hold body position on vibrating platforms with hands grasping on a front support. The aim of this study was to study the response of lower limb tissues to varied vibration frequencies and angle knee flexion during static body position by measuring thigh and leg muscles activity and the transmissibility function of input vibration across lower body joints.