Falls are a significant cause of death and disability and have a a serious impact to the psychological and physical health of the elderly.
Falls is a major cause of severe nonfatal injuries and common cause of hospital admissions (40%) for traumatic injuries among older adults. (Evans, 1996) Falls are also the second leading cause of spinal cord and brain injury among older adults . Approximately 30 ~ 50 % of falls result in minor soft tissue injuries (Nevitt et al., 1989). Overall, 20~30% of those who fall suffer from moderate to severe injuries that limit mobility and independence, even the risk of death (Alexander et al., 1992). The total direct cost of all fall injuries for people age 65 and older in 1994 was 20.2 billion, and it is projected to increase to 32.4 billion by 2020.