Modifiable performance domain risk-factors associated with slip-related falls.

Falls are a major source of injury in older adults. Many falls occur after slipping. This study determined performance-related factors that both contribute to slip-related falls and that may be effectively and efficiently modified through targeted intervention. Thirty-five young adults and 21 healthy older adults (age: 70.9+/-5.1 years) were slipped in a laboratory using a slippery surface. The biomechanics of the 18 older adults who fell and the 30 younger adults who recovered following slips were analyzed. A set of potentially modifiable variables, initially based on significant between-groups differences, was further analyzed using stepwise discriminant analysis and logistic regression. The discriminant analysis correctly categorized 93.8% of the falls and recoveries based on two variables; the velocity of the slipping foot relative to the velocity of the whole body center of mass (COM), and the lateral placement of the recovery foot relative to the COM. The logistic regression determined the expected change in the odds of a recovery following a slip given a hypothesized intervention-induced improvement of these variables. Decreased velocity of the slipping foot relative to the COM, or decreased lateral placement of the recovery foot relative to the COM to zero, increased the odds of recovery by 17% and 27%, respectively. This suggests that intervention targeted at improving these specific lower extremity control variables following the onset of a slip has the potential to significantly decrease slip-related fall risk.