Tham khảo tài liệu 'mechatronics for safety, security and dependability in a new era - arai and arai part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 14 Although falling is a result of complex and multi-factorial problem lack of postural control is one of the major contributing factors. Aging effects on the sensory feedback have been hypothesized to be a key factor in adjusting posture to maintain their balance against unpredictable external or internal variations of gait. In addition recent randomized controlled trials that have tested the effectiveness of the intervention for elderly have indicated that exercise training significantly increase their aerobic capacity and muscle strength which might result in improvement of the postural stability. Conventionally clinicians have been assessed personnel walking ability based on performance of static balance tests and measure of simple gait factors walking speed cadence step length etc. mostly focusing on quantifying regional amount of body sway variability of gait factors or joint angles. Those methods provide a practical evaluation however the measure of static balance or gait variability itself does not mean that of dynamic stability of walking. Dynamic stability represents a resilient ability to maintain certain continuous cyclic movement by accommodating internal or external perturbations Hurmuzlu et al. 1994 . On the other hand variety of instruments have been used to quantify walking characteristics in a more precise manner by means of the video-based motion capture system goniometry or force plates. However those methods requires considerable setups then limited to laboratorial environments. Recently mechatronics progress made it possible to realize small and low power consumptive accelerometry as a testing tool applicable in the field of medical therapy Aminian eí al. 2002 Ohtaki eí al. 2001 2005 . Some advanced algorithms have been also proposed to evaluate gait performances and dynamic walking stability basing on a simple accelerometry Dingwell et al. 2000 2001 Buzzi et al. 2003 Arif et al. 2004 . Further application of those method to a physical .
