Effects of Arm Restriction on Slips and fall in Young and Older Individuals

Abstract When the human body moves from single support to double support, during the heel contact phase, there is a possibility of a slip-induced fall as the weight acceptance task is being transferred from one foot to another. Exploring the biomechanics of gait in the elderly and young with one or two arms restricted under not only the unknown slippery condition but also the dry floor and known slippery conditions could provide a better understanding of slip and fall mechanics. Twenty-eight individuals (14 young and 14 elderly) with equal number of males and females participated in the study. Individuals were required to walk along a circular track and they were required to walk over dry floor and also exposed to a ‘known’ and ‘unknown’ slippery floor condition. For dry walking conditions, a reduced step length and foot-floor angle, and decreased walking velocities were noted when one or two arms of individuals were restricted. For the known slippery condition, reduced step length and foot-floor angle, and smaller walking and heel contact velocities were used by both younger and older individuals. Average sliding heel velocity, peak sliding heel deceleration and separation between whole body center of mass and sliding heel showed differences for age. For differences between fallers and non-fallers, the variables including average sliding heel velocity, maximum separation between the whole body center of mass (WBCOM), and the maximum difference in velocities between the upper body center of mass (UBCOM) and the lower body center of mass (LBCOM) showed significant differences. For arm restriction, both young and older individuals showed significant differences in maximum wrist velocities for the different arm restriction conditions. The most significant finding was that when the arms of individuals were not restricted, they could have higher differences in velocities between the UBCOM and LBCOM, and still not fall.