Falls are the leading cause of injury deaths among people 65 years and older. The National Safety Council reported that in 2005, 17,700 Americans met their death by falling, and of these deaths, the majority (over 80%) were people over 65 years of age [1]. It is certainly desirable to avoid the fall accidents altogether through developing a comprehensive fall prevention program [2]. However, in case of unavoidable falls, an effective injury-prevention technology is critical to minimize/reduce fall-related physical injuries. Recently, the concept of wearable airbag [3] emerged as one viable and promising injury-prevention approach.