Unintentional falls are the number one cause of accident-related death in older and frail adults. One out of five falls causes a serious injury, such as broken bones or a head injury. Each year, 2.5 million older people are treated in emergency departments for fall injuries, and over 700,000 patients a year are hospitalized because of a fall injury, most often because of a head injury or hip fracture. More than 95% of hip fractures are caused by falling, usually by falling sideways, and falls are the most common cause of traumatic brain injuries (TBI). Adjusted for inflation, the direct medical costs for fall injuries are $34 billion annually, and hospital costs account for two-thirds of the total.