The long term goal of this proposed research is to reduce occupational related injuries caused by slips and falls. Accurate assessment of the slip resistance of the shoe/floor interface is critical to determine slip and fall potentials. There are numerous devices that measure slip resistance of a shoe/floor interface; however, these devices do not agree with one another, and there are no valid criteria to evaluate the devices. This proposal focuses on the development of a biomechanical basis for the evaluation of slipperiness. More specifically, a logical regression model relating the required coefficient of friction (RCOF) and measured coefficient of friction (COF) to slips/falls probability will be developed. The slip resistance will be evaluated using four different measurement devices. This study will vary the COF (i.e., slip resistance) through changing the environmental conditions (shoe/floor/contaminant combinations) and the RCOF through varying ramp angles. In experiment #1, subjects will be asked to walk up and down ramps of different inclinations. In experiment #2, the effects of carrying a load on the parameters of the logistic regression model will be investigated. Foot forces and heel dynamics will be measured during the trials. The logistic models will be used not to only predict slips and falls potential but also to compare the ability of different slip resistance measurement devices to predict slips and falls. Parameters from the models will characterize the utility of the four devices. Thus, the efficacy of slip resistance testing in the prevention of slips and falls can be evaluated by comparing slip and/or fall events with slip resistance measures and the biomechanical requirements. Kinematic gait parameters will be monitored. The effect of heel velocity at heelstrike is believed to affect slips and falls probability. Thus, this proposed research will compare the statistical parameters of the model among three categories of heelstrike velocities: low, intermediate and high heelstrike velocities. The stride length and heel velocities will be monitored to detect any change in the gait pattern when subjects are exposed to slippery surfaces. This information will provide an insight on the human reaction to slip potential and possible techniques adopted to recover and/or maintain postural balance. Finally, the relationship between the measured COF and subjective rating of slip resistance will be studied. They will also investigate whether the subjective rating of slipperiness is affected by the task performed or whether a slip/fall has occurred.
| Cham, R; Redfern, M S (2001) Lower extremity corrective reactions to slip events. J Biomech 34:1439-45 |
