Winter Footwear Research Articles

A novel method to predict slip resistance of winter footwear using a convolutional neural network

Slips and falls on ice are common causes of injury in the winter and can result in economic loss. Using slip resistant winter footwear is a key factor in reducing the risk of slips and eventually falls. In this study, we develop a model that classifies footwear outsoles based on how slip resistant they are on icy surfaces. Our dataset consisted of outsole images of 89 winter footwear samples that were previously tested and rated with a human-centred protocol called the Maximum Achievable Angle (MAA). We applied a transfer learning technique where the best classification model used the DenseNet169 pre-trained model and obtained an accuracy and F1-score of 0.93 ± 0.01 and 0.73 ± 0.03, respectively. Our results suggest that the proposed model was able to properly identify high and low slip resistance quality tread patterns. Our findings confirmed that a footwear’s tread pattern has a direct impact on its slip resistance. The proposed model will help footwear manufacturers to improve their workflow and increase product quality which can ultimately decrease the events of slips and falls.

Development and Evaluation of a Slip Detection Algorithm for Walking on Level and Inclined Ice Surfaces.

Slip-resistant footwear can prevent fall-related injuries on icy surfaces. Winter footwear slip resistance can be measured by the Maximum Achievable Angle (MAA) test, which measures the steepest ice-covered incline that participants can walk up and down without experiencing a slip. However, the MAA test requires the use of a human observer to detect slips, which increases the variability of the test. The objective of this study was to develop and evaluate an automated slip detection algorithm for walking on level and inclined ice surfaces to be used with the MAA test to replace the need for human observers. Kinematic data were collected from nine healthy young adults walking up and down on ice surfaces in a range from 0° to 12° using an optical motion capture system. Our algorithm segmented these data into steps and extracted features as inputs to two linear support vector machine classifiers. The two classifiers were trained, optimized, and validated to classify toe slips and heel slips, respectively. A total of approximately 11,000 steps from 9 healthy participants were collected, which included approximately 4700 slips. Our algorithm was able to detect slips with an overall F1 score of 90.1%. In addition, the algorithm was able to accurately classify backward toe slips, forward toe slips, backward heel slips, and forward heel slips with F1 scores of 97.3%, 54.5%, 80.9%, and 86.5%, respectively.

The effect of wear on slip-resistance of winter footwear with composite outsoles: A pilot study

Falls on icy surfaces are among the top causes of injuries for workers exposed to the outdoor environment. Our recent field study showed that a new generation of winter footwear incorporating composite outsoles was able to reduce slips and falls on icy surfaces by 68% and 78%, respectively. The widespread adoption of this type of footwear may lead to substantial reductions in pain, suffering and costs of fall-related injuries. However, these composite materials are sensitive to wear and abrasion, which makes it likely that their slip-resistance performance may degrade with use. The goal of this pilot study was to determine the extent to which the slip-resistance of two types of winter footwear with composite outsoles changed as they wore down with real-world use. Seven participants were recruited for this study and were asked to walk 100K steps with their assigned footwear. Tread depth and slip–resistance performance (using the Maximum Achievable Angle test) were measured at baseline and again after each 25K-step interval up to 100K. Our results showed that the slip-resistance performance of the test footwear dropped significantly after the 75K and 100K step intervals compared to baseline. In addition, significant changes in tread depth were found after only 25K steps. These findings indicate that the performance of this type of footwear degrades relatively quickly with real-world use. Therefore, larger scale study of the slip-resistance of winter footwear with composite outsoles is needed and members of the public should be made aware of the potential loss of slip-resistance of these products.

A novel approach for slip resistance evaluation of winter footwear based on probability of slipping and cost analysis

This paper proposes a slip-prediction model to estimate the probability of footwear slipping on ice. The mode is based on slips that are induced when human subjects are challenged by walking in a test chamber with full control over environmental conditions. This technique will help to evaluate the slip resistance quality of winter footwear in an ecologically valid manner. Four styles of winter footwear were tested by 8 participants on wet and dry ice surfaces with different slopes. The tests were repeated three times on different days. The probability of slipping was estimated for each incline angle using logistic regression analysis with three predictors: angle, ice condition and walking direction. In order to rank the quality of the winter footwear, a comprehensive cost analysis was performed to estimate the misclassification cost from the logistic regression. This method makes no assumption regarding the distribution of the data. The probability cutoff for each footwear style is obtained by minimizing the misclassification cost. The results show that increasing the incline angle significantly increases odds of slipping for all four styles (p<0.01). In addition, as indicated by the results, different styles of footwear perform differently on the various winter surfaces. Therefore, this method is able to rank the slip-resistance property of the footwear based on the probability of slipping.

Evaluation of Winter Footwear: Comparison of Test Methods to Determine Footwear Slip Resistance on Ice Surfaces.

The use of slip-resistant winter footwear is crucial for the prevention of slips and falls on ice and snow. The main objective of this paper is to evaluate a mechanical testing method to determine footwear slip resistance on wet and dry ice surfaces and to compare it with the human-centred test method introduced by researchers at KITE (Knowledge, Innovation, Talent, Everywhere)-Toronto Rehabilitation Institute-University Health Network. Phase 1 of this study assessed the repeatability and reproducibility of the mechanical method by evaluating ten different occupational winter boots using two SATRA Slip resistance testers (STM 603, SATRA Technology Centre, Kettering, UK). One tester is located in Toronto and one in Montreal. These boots were chosen based on the needs of the IRSST (Institut de Recherche Robert-Sauvé en Santé et en Sécurité du Travail, Montréal, Quebec, Canada), who were primarily interested in providing safe winter footwear for police, firefighters and municipal workers. In Phase 2, the results of the human-centred test approach were compared with the mechanical results. In Phase 3, two of these boots with conflicting results from the previous phases were tested using a second human-centred method. In Phase 1, the mechanical testing results obtained in the two labs showed a high linear correlation (>0.94) and good agreement on both ice surfaces; however, they revealed a bias (~0.06) between the two labs on the dry ice condition. The mechanical and human-centred tests (phase 2) were found to be better correlated in the wet ice condition (R = 0.95) compared to the dry ice condition (R = 0.34). Finally, the rating of the footwear slip resistance based on the number of slips counted in phase 3 was consistent with the rating by the human-centred test method (phase 2), but not the mechanical method (phase 1). The findings of this study provide a better understanding of the limitations of the SATRA ice tray for measuring footwear slip resistance and demonstrate that the mechanical method must be further refined to make it more comparable to the human-centred methods to achieve better agreement with real-world performance.

Reducing fall risk for home care workers with slip resistant winter footwear

Falls on icy surfaces are the leading cause of occupational injuries for workers exposed to outdoor winter conditions. Slip resistant footwear has been shown to reduce the risk of falls for indoor workers but until recently, there was no accepted standard for evaluating the slip resistance of winter footwear on icy surfaces. Our team recently developed a lab-based testing protocol for measuring footwear slip resistance. This protocol, called the Maximum Achievable Angle (MAA) test, measures the steepest ice-covered slope that participants can walk up and down without experiencing a slip in a simulated winter environment. This lab-based protocol has found there is wide variability in the performance of commercially available winter footwear. In particular, we have found that a new generation of footwear that incorporates composite materials in the outsole, performs much better than most other footwear.The objective of this project was to investigate whether the footwear that performed well in our lab-based testing would reduce the risk of slips and/or falls in real-world winter conditions. One hundred and ten home healthcare workers from SE Health were recruited for this study and were asked to report their exposure to icy surfaces along with the numbers of slips and numbers of falls they experienced each week using online surveys over eight weeks in the winter. Fifty participants (the intervention group) were provided winter footwear that were among the best performing in the MAA test. The remaining sixty participants (the control group) wore their own footwear for the duration of the study.A total of 563 slips and 36 falls were reported over the eight-week data collection period. The intervention group consistently reported fewer slips (127 vs 436) and fewer falls (6 vs 30) compared to the control group. We found the slip rate in the intervention group was between 68.0% and 68.7% lower than the control group. Similarly, the fall rate was between 78.5% and 81.5% lower in the intervention group compared to the control group. These findings demonstrate that footwear that performs well in the MAA test can reduce the risk of both slips and falls in real-world winter conditions.

Selecting slip resistant winter footwear for personal support workers.

BACKGROUND:Falls are among the leading causes of occupational injuries for workers exposed to outdoor winter conditions such as Personal Support Workers (PSWs). Slip resistant footwear is known to reduce the risk of falls, however, it is difficult to predict how well a particular boot will perform prior to purchasing them. Our recently developed Maximum Achievable Angle (MAA) test can be used to rate footwear objectively to address this gap.OBJECTIVE:To rate the slip resistance of a selection of winter footwear that meets the needs and preferences of PSWs.METHODS:We selected 40 representative types of footwear based on survey results from 677 PSWs and applied our MAA test to rate slip resistance.RESULTS:Comfort and slip resistance were rated the most important features for selecting winter footwear. Of the 40 types of footwear tested, six were found to have a good slip resistance on ice.CONCLUSION:The vast majority of winter footwear that meet the needs and preferences of PSWs, perform poorly on ice. Therefore, PSWs should consult our website (ratemytreads.com) for selecting appropriate footwear that will keep them safe in the winter.

Slip resistance and wearability of safety footwear used on icy surfaces for outdoor municipal workers.

BACKGROUND:Outdoor workers experience high injury rates in the winter due to slipping on ice and snow. Our testing program has demonstrated that most safety footwear does not provide adequate slip-resistance and/or comfort in icy conditions.OBJECTIVE:Our objective was to determine which of the most commonly worn safety footwear available to outdoor municipal workers in Toronto, Ontario, Canada would best prevent slips on icy surfaces and which models had good wearability.METHODS:We selected 45 of the most popular types of winter footwear worn by these workers and applied our Maximum Achievable Angle (MAA) test method to rate the slip-resistance of the footwear. A ten-point rating scale was used for recording participants’ perceptions of wearability. The MAA test measured the steepest ice-covered incline that participants can walk up and down without experiencing a slip.RESULTS:Of the 45 types of footwear tested, only one model achieved an MAA score of 8 degrees that exceeded our cut-off for acceptable performance set at 7 degrees. Secondary measures of performance including thermal insulation; wearability and heaviness of footwear tested were also ranked.CONCLUSION:Our results demonstrate that footwear manufactures have the opportunity to differentiate their footwear by investing in slip-resistant outsole materials.

Effects of multi-functional surface-texturing on the ice friction and abrasion characteristics of hybrid composite materials for footwear

There is growing demand for composite materials for use with slip-resistant footwear. This paper reports on the optimization of a surface-textured hybrid composite material with good slip-resistance on ice. Our material has a unique design consisting of a soft rubber compound reinforced with a combination of soft and hard microscopic fibers embedded within it that protrude out from its surface. These fibers can penetrate icy surfaces, while the soft rubber component deforms to mold against hard substrates resulting in mechanical interlocking.Our previous work has shown our initial formulations of this composite has superior slip-resistance and abrasion resistance compared to other materials on the market. The objective of this work was to systematically vary manufacturing (fiber content and molding temperature) and testing parameters (normal load and sliding velocity) to evaluate the effects on slip-resistance before and after abrasion.Our hybrid thermoplastic polyurethane (TPU) composites composed of carbon fiber (CF) and poly (p-phenylene-2,6-benzobisoxazole) (PBO) fibers were fabricated by means of compounding followed by ablation. The coefficient of friction on ice was measured before and after simulated wear using SATRA STM 603 slip-resistance testing machine (SATRA). The surface morphology of each composite was also characterized visually using scanning electron microscopy (SEM). The set of experiments used was derived by applying the Taguchi method for robust design.The optimal combination of parameters maximizing the coefficient of friction on ice after abrasion was determined. Before abrasion, the only control factor that affected the ice friction properties of the composite was fiber content (p = 0.024). After abrasion, ice friction was independent of all control factors with no interaction effects and no sensitivity to the testing parameters, indicating the capability of the material to retain its slip-resistance even after extensive wear (COF = 0.61 ± 0.05). The SEM images indicated that there was significant fiber protrusion from the textured surfaces after abrasion. These findings suggest that our hybrid composite material has good potential for use in applications such as winter footwear for providing traction on icy surfaces even after extended use.

Elastomer Composites with Enhanced Ice Grip Based on Renewable Resources

Slips and falls on icy surfaces can cause serious injuries of people. The primary risk factor for slipping incidents is undoubtedly the decreased friction coefficient between the shoe sole and the ice or snow surface. Nowadays environmental protection has been gaining significance and becoming highly important for the various innovation strategies. In rubber industry the concept of environmental protection is more often associated with the maximum use of elastomers and ingredients from renewable sources in the manufacture of rubber products. The aim of this work is to investigate the possibilities of using elastomers and ingredients from renewable sources—epoxidized natural rubber, silica obtained by rice husks incineration and microcrystalline cellulose—as fillers and rapeseed oil as a process additive in compositions, intended for the manufacture of soles for winter footwear having an increased coefficient of friction to icy surfaces. The tribological tests based on the coefficient of friction evaluated the adhesion of the composites to the icy surfaces at different temperatures. The complex evaluation of developed composites revealed those containing microcrystalline cellulose and biogenic amorphous silica at a 1:1 ratio as the most suitable for making footwear soles because of the best combination of physicо-mechanical properties and coefficient of friction.

Slip resistance of winter footwear on snow and ice measured using maximum achievable incline

Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear–surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance.Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established.

Assessing the performance of winter footwear using a new maximum achievable incline method

More informative tests of winter footwear performance are required in order to identify footwear that will prevent injurious slips and falls on icy conditions. In this study, eight participants tested four styles of winter boots on smooth wet ice. The surface was progressively tilted to create increasing longitudinal and cross-slopes until participants could no longer continue standing or walking. Maximum achievable incline angles provided consistent measures of footwear slip resistance and demonstrated better resolution than mechanical tests. One footwear outsole material and tread combination outperformed the others on wet ice allowing participants to successfully walk on steep longitudinal slopes of 17.5° ± 1.9° (mean ± SD). By further exploiting the methodology to include additional surfaces and contaminants, such tests could be used to optimize tread designs and materials that are ideal for reducing the risk of slips and falls.

Ridiculous/Hilarious/Terrible/Cool: A Year in an American High School (review)

Reviewed by: Twelve Rounds to Glory: The Story of Muhammad Ali, and: Muhammad Ali: Champion of the World Elizabeth Bush Smith, Charles R., Jr. Twelve Rounds to Glory: The Story of Muhammad Ali; illus. by Bryan Collier. Candlewick, 200780p ISBN 978-0-7636-1692-2$19.99 Ad Gr. 5-9 Winter, Jonah Muhammad Ali: Champion of the World; illus. by François Roca. Schwartz & Wade, 200734 p Library ed. ISBN 978-0-375-93787-3$19.99 Trade ed. ISBN 978-0-375-83622-0$16.99 M 6-9 yrs Cooper went back to school for a year, tagging around after a handful of students at Walter Payton College Preparatory High School in Chicago and coaxing revelations about their interests, activities, and aspirations. Rather than an interview-style report, however, he spins his discoveries into a monthly survey of how everybody's getting by, with cuts from scene to scene as swift as a prime-time hospital or cop drama. Readers meet Daniel, an African-American student with his sights set on Harvard and a career in politics; soccer star Emily, whose year-end makeover does nothing to soften her fierceness on the field; Diana, the first in her Latino family to have a shot at college; Anais, perplexed about whether to pursue her passion for dance in a college program or with a troupe; and Aisha, a Muslim girl who seldom forms friendships since her family is constantly on the move. Not all are high achievers—there's Zef, whose dysfunctional sleep habits get him booted from Payton and relegated to an alternative program through a community college; and Anthony, whose complicated love life and petty drug dealing leave him no room for study, only a post in the cafeteria from which he seldom moves. Cooper maintains a reportorial distance from his subjects and an unfailingly nonjudgmental perspective, and he displays a keen eye for what really matters at the moment, from college acceptance letters to the sartorial challenges of winter footwear in Chicago. Teeny gray-tone vignettes punctuate the text and extend Cooper's impressionistic take on high-school life. No dates are mentioned, but references to the White Sox World Series, Christmas season at Marshall Field's (now, oh-so-sadly, Macy's), and Dick Cheney's hunting accident place this unmistakably in the 2005-6 academic year, a freshness date that's certain to expire pretty soon. All the more reason to get this title into circulation quickly. Copyright © 2008 The Board of Trustees of the University of Illinois

A Simple Gait‐Stabilizing Device Reduces Outdoor Falls and Nonserious Injurious Falls in Fall‐Prone Older People During the Winter

To determine whether Yaktrax Walker (YW), a nonmedical gait-stabilizing device, prevents outdoor falls and injurious falls in fall-prone older people during the winter. Prospective, randomized, interventional trial. Community-based, northern United States, winter, outdoors. Ambulatory, community-dwelling, fall-prone people aged 65 and older. Participants were randomized to wear YW or their usual winter footwear (UWF) outdoors during the winter of 2003/2004. The number of indoor and outdoor slips, falls, and injurious falls was recorded daily in a fall diary. Winter footwear satisfaction survey was completed after study completion. One hundred nine subjects completed 10,724 diary days. Mean age was 74.2. There were 93 indoor slips, 13 indoor falls, 714 outdoor slips, and 62 outdoor falls. The tendency for both groups to slip/fall indoors was comparable. The relative risk (RR) of outdoor slip for YW was 0.50 (P<.04) for all diary days and 0.61 (P=.14) when only days walked on snow and ice was the exposure variable. The RR of outdoor fall for YW was 0.42 (P<.03) when only days walked on snow and ice was the exposure variable. RR of injurious falls per day walked on snow and ice for YW was 0.13 (P<.02). Twelve of 19 outdoor falls occurred when YW subjects were not wearing their assigned device. No serious injury or fracture occurred in either group. The number needed to treat for the YW to prevent one nonserious injurious fall in one winter was six. YW may reduce the risk of outdoor winter falls, and of nonserious injurious falls, in older community-dwelling people with a history of previous falls.

Slips and falls on ice and snow in relation to experience in winter climate and winter sport

The objective of this paper was to investigate whether living experience in winter climate and winter sport helps to prevent slips and falls on ice and snow. A questionnaire survey was conducted among foreigners at Luleå University of Technology of Sweden, where winter season lasts for six months in a year. Seventy respondents replied. The results of ordinal regression showed that the slip frequency according to a 5-point rating scale decreased as the living experience in cold environments increased ( B=−0.0113, p=0.019). A logistic regression was applied to model the probability of fall events occurrence based on the experience of living in cold climate. The results showed that the fall events reduced as living experience increased ( B=−0.030, p=0.001). Chi-square test showed that fall events in those who took part in winter sport were significantly less than in those who did not participate in winter sport ( χ 2=10.745, p=0.001). The findings imply that experience of living in cold environments and training in gait balance on ice and snow can have positive effects in preventing slips and falls for inexperienced workers and pedestrians. This study also revealed that the majority of fall events happened on hard ice covered with snow while wearing ordinary winter footwear, indicating the need to improve slip resistance.

Slipperiness of footwear and mechanisms of walking friction on icy surfaces

The coefficient of kinetic friction of 49 types of footwear was determined using a prototype apparatus simulating actual foot slippage on dry and wet smooth ice at surface temperatures of − 10° C and 0° C, respectively. The effects of soling material type, hardness, and tread design on the frictional properties were assessed in particular. In addition the effect of strewing sand on ice was studied. The fundamental mechanisms of the friction of polymers on ice are discussed briefly in the paper. The properties of ice had the greatest influence on the coefficient of kinetic friction, and hence, slip resistance. Of the assessed footwear, over 90% was classified as very slippery on wet ice, and 60% as slippery on dry ice. Five footwear types were slip-resistant on dry ice but only one on wet ice. None were slip-resistant on both wet and dry ice. Soft heel and sole materials (Shore A < 60) of thermoplastic rubber with a cleated area as large as possible are recommended for winter footwear on dry ice. For wet ice, however, new developments are needed, e.g. very hard (Shore A > 85) soling materials with sharp cleats in combination with a softer base material. Strewing sand on ice improved the slip resistance to a safer level, particularly on wet ice.

Evaluation of Synthetic Upper Materials for the Production of Winter Footwear

Evaluation of Synthetic Upper Materials for the Production of Winter Footwear