System for Measurement of the Mechanical Impedance of Human Body During Vibration Training

Vibration training consists of performing dynamic or static squats on a vibrating plate. Exercises are easy to perform, and the risk of the contusion is low. Vibration training may help to preserve the independence of elderly persons, reduce the risk of falls. In consequence, vibration training can improve their quality of life. On the other hand, vibration may cause side effects such as pain and spine injuries. Vibration exposure may be quantified with 'estimated vibration dose value' (eVDV) (ISO 2631-1). During vibration training, safe level of vibrations may be exceed causing detrimental side-effects. eVDV was frequently criticized, as it is assumed that it does not reflect adequately the real load of vibration, therefore better hazard risk factor should be found. In this study, we describe the system to measure electrical power delivered to electro-magnetic vibrator, force, and acceleration acting on the vibration plate. We show changes in mechanical impedance caused by different posture on a vibration platform. Mechanical impedance relates velocity with forces acting on a mechanical system (patient +vibrating platform). Mechanical impedance of patient on the vibration plate can be used to predict vibration amplitude and eVDV.