Falls from standing height are a major source of morbidity and death among the elderly. However, little is known about the movement strategies used to prevent falls and fall-related injuries. The aims of this dissertation were (1) to determine whether specific protective responses are used to avoid injury in the event of a fall, and (2) to determine whether one's ability to recover balance by stepping associates with the kinematics and kinetics of the step. To address Aim 1. perturbation platform experiments were conducted with young subjects, who stood on a gymnasium mat and attempted to avoid falling after the mat was abruptly translated. Subjects were more than twice as likely to fall after forward translations of the feet, when compared to backward or sideways translations. Even after sideways translations, subjects tended to avoid direct impact to the hip. Among the mechanisms responsible for this were axial rotation of the trunk during descent and braking the fall with the outstretched hands. In falls that resulted in impact to the pelvis, a complex sequence of upper extremity movements allowed subjects to impact their wrists at nearly the same instant as the pelvis (average time between contacts = 38 ms), suggesting a sharing of contact energy between the two body parts. To address Aim 2, young and elderly subjects participated in experiments where they were suddenly released from a forward or backward inclination, and instructed to recover balance by taking one or more steps. Data from these experiments and complementary mathematical models suggest that recovery ability associates with the size of the first step, time to execute the step, and torque-generating capacity of the lower extremity joints. For example, an increase of 1 0 in step length caused the maximum recoverable inclination angle to increase by up to 36%. These studies suggest that fall-related injury’ prevention programs for elderly adults should train individuals to (a) recover balance by taking one or more large, quick steps, and (b) in the event of a fall, avoid direct impact to the hip by rotating their trunk during descent and impacting the ground with their outstretched hands.