Impact severity during a fall is decreased by lower extremity muscle contractions during descent

摘要

Falls are a major cause of injury in the elderly, including the vast majority of hip and wrist fractures, and a considerable portion of vertebral fractures. In the event of a fall, one's risk for such an injury depends on bone strength, and theconfiguration and kinetic energy (KE) of the body at the instant it contacts the ground. Consideration of acts such as sitting and squatting suggests that a major determinant of KE is the amount of energy "absorbed" (or negative work performed) during the descent phase of the fall by eccentrically-contracting lower extremity muscles. In the present study, we used a computational model of backwards falling to address the following questions: (1) what degree of impact energy attenuation might be achievedthrough muscle contraction during the descent phase of falling? and (2) what is the relative importance of muscle contractions at the hip, knee, and ankle in attenuating impact energy?