ABSTRACT
Slips, trips, and falls (STF) can cause serious harm or death. The biomechanics of slip have been extensively studied in the literature. Understanding the biomechanics of slip is the beginning of developing prevention strategies for STF and allows one to develop slip-resistant footwear and other technologies as well as understanding the difference between slips that lead to recovery and those that result in falls. It is generally understood that there are certain key factors that can contribute to slips. Ground reaction forces at the shoe-floor interface have been determined to be a critical biomechanical factor in slips (Redfern et al., 2001). Other biomechanical factors known to influence slip include: the kinematics of the foot at heel contact, human responses to slipping perturbations, the mental state of the individual, the individual's perception of the environment, the individual's age, walking speed, compensatory stepping, trained exposure to slips, and gait stability. One property of the shoe/floor interface that is closely associated with slip is the coefficient of friction (COF). Often, the COF is compared to the ratio of shear to normal foot forces generated during gait, which is known as the required coefficient of friction (RCOF). In early simplistic STF studies, it was held that the condition for slip was when the RCOF was less than the COF. However, it was proven that this is not always the case. Now there are more complicated expressions that predict the probability of slip under certain conditions. In addition to biomechanical factors that influence slip, there are environmental factors that influence slip probability. 24Environmental factors include: temperature; presence of rain, ice, and snow; presence of obstacles or ramps; and surface characteristics of the floor/surface such as roughness and waviness. In addition to studies on the biomechanics of slip, biomechanical factors of slip, and environmental factors of slip there are numerous studies on STF as it relates to occupational hazards. Survey-based studies have been conducted for occupations with a high risk of STF including: hospital and healthcare workers, postal workers, construction workers, and fast-food/restaurant workers. Other non-occupational survey-based studies on STF include: STFs from ladders, STFs and nursing homes, and STFs during bathtub/shower ingress and egress. While there is a great deal of literature on the biomechanics of slip and STF detection and prevention, most of the knowledge on STF has been obtained from conducting surveys and experiments that test various conditions and environments where STF is common. In contrast to the amount of experimental work done on STF there are limited studies available that propose probabilistic or simulationbased methods of STF detection and prevention. This paper aims to present a comprehensive literature review about probabilistic or simulation-based methods for STF. Based on the literature review, we would like to develop a more efficient simulation-based STF method.
