Slip and fall risk on ice and snow : identification, evaluation and prevention

Abstract: Slip and fall accidents and associated injuries on ice and snow are prevalent among outdoor workers and the general public in winter in many regions of the world. To understand and tackle this multi-factorial problem, a multidisciplinary approach was used to identify and evaluate slip and fall risks, and to propose recommendations for prevention of slips and falls on icy and snowy surfaces. Objectives were to present a systems perspective of slip and fall accidents and related risk factors; to evaluate the integration of slip resistance, thermal insulation, and usability of footwear by subjective trials. Further, to study the interaction mechanisms between footwear soling material and ice; to investigate and describe the relationship of ice and snow living experience and participation in winter sports with slips and falls; and to explain the role and mechanisms of lower extremity muscles in maintaining gait dynamic balance on inclined icy surface. The following methods were applied: 1) a systematic analysis of multiple risk factors through literature review; 2) direct observation; 3) videotaping; 4) subjective evaluations of slipperiness, thermal comfort and usability using rating scales; 5) a tribological study of the Coefficient of Friction (COF); 6) a questionnaire survey to identify and evaluate risk factors related to slips and falls; 7) a biomechanical study of human locomotion on ice. A systematic analysis of slips and falls on icy and snowy surfaces made it possible to use a multi-faceted approach to evaluation and prevention. The slip resistance, thermal insulation and usability of footwear tested were not suitably integrated, indicating the need of improving anti-slip properties and usability of footwear for use in cold environments. The artificially abrasive wear of soling materials improved slip resistance on hard ice, but not on melting ice. When comparing hard ice, melting ice and lubricated steel surfaces, the highest slip resistance was observed on hard ice, then on lubricated steel plate. Melting ice was most slippery. Curling footwear with crepe rubber soling showed significantly higher COF than other types. The footwear tested included winter footwear, professional footwear, safety footwear, and footwear considered to be slip resistant by manufacturers did not provide adequate protection against slips and falls on melting ice. Thus, additional measures should be taken to reduce slip and fall risk on melting ice. Slip and fall events declined with increased living experience in cold environments and winter sports participation. Biomechanical studies showed both increased and decreased magnitudes of gait muscle activities (EMG) at different gait phases and a generating of cautious gait strategies with an anticipated icy surface. These findings provided insights into how the proactive kinetic and kinematic adjustments of gait are achieved and the control mechanisms of stabilizing gait and posture through certain muscle activities when ascending on an icy slope. The mechanisms identified may be applied to develop intervention, rehabilitation and training techniques, which prevent slip and fall risks and associated injuries on icy surfaces and to improve performance in human locomotion, e.g., for winter sports. Measurement methods of slipperiness on ice and snow, related standards, task-related factors, slip resistant footwear, and intervention programs should be further studied and developed.