Effect of Sweating on Insulation of Footwear

The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19–25% (30–37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.     

Impact of work boots and load carriage on the gait of oil rig workers

Effects of work boots and load carriage (6.4?kg and 12.8?kg) on gait pattern were investigated. The protective work boots were examined by comparison with running shoes through human performance tests with 15 male participants. The loads were carried symmetrically and asymmetrically on the shoulder and hand. Statistical data analysis showed a prolonged stance phase and decreased double support for work boots. A significantly increased ground reaction force was found in work boot conditions as the weight of loads increases. This study demonstrates that inflexible and heavy work boots restrict foot movement and require greater torque at the ankle to propel the body forward, which may increase physical strain and the risk of musculoskeletal injuries. Development of improved fixation methods for work boots, increased use of flexible protective layers and further study of anthropometry of human foot morphology for improved safety and work efficiency of industry workers are suggested.     

A Comparison of Two Methods of Determining Thermal Properties of Footwear

The present European Standard for footwear testing (Standard No. EN 344:1992; European Committee for Standardization [CEN], 1992) classifies footwear thermally by a temperature drop inside the footwear during 30 min at defined conditions. Today, other methods for footwear thermal testing are also available. The aim of this study was to compare EN 344:1992 with a thermal foot method. Six boots were tested according to both methods. Additional tests with modified standard tests were also carried out. The methods ranked the footwear in a similar way. However, the test according to standard EN 344:1992 is a pass-or-fail test, whereas data that is gained from the thermal foot method gives more information and allows further use in research and product development. A change of the present standard method is suggested.     

Performance of slippery and slip-resistant footwear in different wintry weather conditions measured in situ

In Finland about 70,000 people are annually injured in pedestrian and bicycle falling accidents occurred at the street, walkways and courtyards. Around 2/3 of these occur when the walking surface is covered by ice or snow. In general, slipping is caused by both environmental and human factors. The primary environmental factor behind slipping accidents is slip resistance characteristics of underfoot surface. Especially in winter slipping accidents are mainly due to inadequate friction between footwear and underfoot surfaces. Portable devices measuring friction, i.e. slipmeters, may be used for assessing slipperiness on different walking surfaces in situ. During winter seasons 2003 and 2004 a study was performed to evaluate the usability of portable slip simulator for measuring slipperiness of walkways on varying weather conditions and to assess slip resistance of different footwear. The Portable Slip Simulator proved to be applicable for measuring in situ the slipperiness of wintry walking surfaces and evaluating quality of winter maintenance. Significant differences in traction between footwear were found especially in normal Finnish climate winter days when friction provided by slip-resistant footwear was multifold compared to a poorer one. On very slippery icy surfaces no footwear provided enough grip and, therefore, in such conditions anti-slip devices should be used.     

A comparison of required coefficient of friction for both feet in level walking

The required coefficient of friction (RCOF) is one of the critical elements in determining whether a slip incident might occur. Most researchers, when measuring RCOF, do not differentiate between the two feet of the same participant under the same walking condition. Results from a recent study (Chang et al., 2010) indicated that the stochastic distributions of the RCOF of both feet were different in 76% of the cases. Using the previous data (Chang et al., 2010), this paper presents a comparison of the RCOF for both feet of 50 participants under four level walking conditions resulting from two footwear types and two walking speeds using a t-test, commonly used by safety professionals to compare two pools of data. The current results indicated that 78% of the RCOF data showed a statistically significant difference between the RCOF from two feet for the same participant under each walking condition. The results of the logistic regression analysis used to identify factors that contributed to the outcome of the t-test indicated that the walking speed was the only factor with a statistical significance (p = 0.044).     

保暖鞋鞋底保暖结构研究

本文结合鞋靴保暖功效学原理,重点研究了支撑式鞋垫和橡胶双密度胶底结构。通过实验确定了鞋底发泡层视密度的范围在0.75g/cm3～0.85g/cm3之间,发泡橡胶的拉伸和导热性能达到平衡,兼顾了保暖鞋的耐穿和防寒隔热性能。     

Influence of trunk muscle activity and stability in front and back holding

Purpose. A tandem carrying style is often used in the workplace, but carrying approaches are different for two people because of the holding load in the tandem posture. To understand these carrying styles, this study aimed to investigate the patterns of muscle activity and stability of the trunk influenced by front and back holding of a heavy load. Methods. Electromyography data of eight trunk and two hip muscles, as well as displacements of the trunk, were recorded for analysis while subjects stood statically holding a handle in the front and back of the body with and without load. Results. Without load, muscle activities during front holding mirrored those during back holding. With load, greater muscle activities were observed in the dorsal muscles of the trunk and lesser activities were noted in the ventral muscles in the two holding styles. More frequencies of trunk oscillations occurred in front holding with and without load. Conclusions. The results revealed that back holding of load created more stability of the upper body, whereas front holding resulted in more instability of the trunk.     

Friction measurements on ramps using the Brungraber Mark II slipmeter

It is a common belief that a person is more likely to slip when walking on an inclined surface than when walking on a level surface. Reports of friction measurements were common on horizontal surfaces but were rare on inclined surfaces. A slip measurement device reports different readings on the same surface with different inclined angles if the effect of gravity comes into play. In this study, friction measurements were conducted on the same surface with 0°, 10° and 20° inclined angles under different footwear materials, floors, and surface conditions, using a Brungraber Mark II slipmeter. Statistically significant results were obtained for the measurement results under the inclined angle, footwear material, floor, and surface conditions. A regression model was established to describe the coefficients of friction on ramp floors under footwear material/floor/surface conditions. This model is significant at p < 0.0001 with an R² of 0.87. The cosine function of ramp angle, as suggested in the regression model, was recommended to be used as a correcting factor for friction measurement results using the Brungraber Mark II on ramps to report the corrected friction coefficient of the surfaces.     

Traction performance across the life of slip-resistant footwear: Preliminary results from a longitudinal study

Introduction: Slips, trips, and falls are a major cause of injury in the workplace. Footwear is an important factor in preventing slips. Furthermore, traction performance (friction and under-shoe fluid drainage) are believed to change throughout the life of footwear. However, a paucity of data is available for how traction performance changes for naturally worn, slip-resistant footwear. Method: The presented research is a preliminary analysis from an ongoing, larger study. Participants wore slip-resistant footwear while their distance walked was monitored. Friction and under-shoe fluid pressures were measured using a robotic slip tester under a diluted glycerol contaminant condition after each month of wear for the left and right shoes. The size of the worn region was also measured. Results: Friction initially increased and then steadily decreased as the distance walked and the size of the worn region increased. Fluid pressures increased as the shoes were worn and were associated with increased walking distance and size of the worn region. Discussion: Consistent with previous research, increases in the size of the worn region are associated with increased under-shoe fluid pressures and decreased traction. These trends are presumably due to reduced fluid drainage between the shoe-floor interface when the shoe becomes worn. Conclusions: Traction performance changes with natural wear. The distance walked in the shoe and the size of the worn region may be valuable indicators for assessing loss of traction performance. Practical Applications: Current shoe replacement recommendations for slip-resistant shoes are based upon age and tread depth. This study suggests that tools measuring the size of the worn region and/or distance traveled in the shoes are appropriate alternatives for tracking traction performance loss due to shoe wear.     

BS EN ISO 20345：2011《个体防护装备安全鞋》标准的解析和建议

本文通过对最新的BS EN ISO 20345：2011《个体防护装备安全鞋》标准的列表介绍和概括性分析,找出了新标准检测项目仍存在的遗留问题和未考虑到的缺陷以及需要界定的术语,并提出了今后标准的再修订意见。此再修订意见的给出,为推动今后与安全鞋标准BS EN ISO 20345：2011属于同一体系的我国GB 21148-2007《个体防护装备安全鞋》标准修订提供参考意见。     

Investigation and identification of factors affecting migrating peasant workers’ usage of safety footwear in the Chinese construction industry

A sample of 300 migrating peasant workers from 15 Chinese building construction sites completed a demographic questionnaire to investigate the usage of safety footwear. The survey form was constructed based on the theory of planned behaviour, and a total of 12 questions focusing on the workers’ past experience, attitudes, subjective norms and perceived behavioural control were included in the survey. It was found that 92% of the participants did not wear safety footwear while working on construction sites, although more than 91% of them believed that safety footwear would protect the foot from injury; none of the participants had been provided free safety footwear by their employer. Regression analysis shows that employers’ attitude is the most important factor affecting their usage of safety footwear, ‘providing free safety footwear’ and ‘comfortability of the safety footwear’ ranking second and third respectively.     

Gender response and safe carrying load limit for sugar industry workers

This study investigates the safe carrying load limit in relation to gender of workers in the sugar industry. A total of 632 workers (male and female) were interviewed following a physiological and psycho-physiological methodology. All of these workers were in the age groups of 21–30, 31–40 and ≥41 years. In this study, for the physiological methodology, both field and laboratory data were collected, which included heart rate, heart rate variability, energy expenditure and maximum rate of oxygen consumption. Information regarding hemoglobin content, weight, age, lean body weight, etc., was recorded to know the physical health of the workers. In the psycho-physiological evaluation, load-carrying limits were determined by the psychophysical rating of the load by workers from the selected age groups. By considering the physiological stresses and psycho-physiological evaluation, the safe carrying load limit was determined in head and back mode for male and female workers as per their age groups.     

Reaction Moment at the L5/S1 Joint During Simulated Forward Slipping With a Handheld Load

The purpose of the study was to investigate the effects of load on the net moment response at the L5/S1 joint during simulated slip events. Six young individuals were instructed to take one step with a handheld load. Sudden floor movement was randomly introduced to simulate unexpected slips. Different loads conditions (0%, 10%, 20%, 30% of body weight) were introduced at random. Three-dimensional net moments at the L5/S1 joint were computed via downward inverse dynamic model. Peak joint moment generated at 30% load level was found to be significantly higher compared to no-load condition. No peak moment differences were found among no-load, 10% or 20% load levels. Additionally, the findings from this study indicated a flexiondominant net L5/S1 joint moment pattern during motion phase associated with slip-induced falls.     

The use of footwear insulation values measured on a thermal foot model.

The use of physiological data from human tests in modelling should consider background data, such as activity, environmental factors and clothing insulation on the whole body. The present paper focuses on local thermal comfort of feet with special attention on the effects of physical changes of footwear thermal properties. An alternative test method is available for footwear thermal testing besides the standard method. The possibility to use insulation values acquired on a thermal foot model in practice is shown here. The paper describes the correlation between cold and pain sensations, and foot skin temperatures of the subjects and relates these to insulation measured on a thermal foot model. Recommendations are made for footwear choice according to environmental temperature.     

特种劳动防护鞋检测有关问题探讨

通过对特种劳动防护鞋的检测,对检测质量的保证因素和在检测中发现的问题进行分析与探讨.特种劳动防护鞋的质量问题是检测合格率低的主要因素,国家标准的采用及理解是检测工作的基础,规范的检测操作是保证检测结果准确性的重要因素.     

The Surface Roughness of a Rubber Soling Material Determines the Coefficient of Friction on Water-Lubricated Surfaces

For more than a decade, evidence has been accumulating that points to the fact that the microscopic roughness of the footwear soling surface is a major determinant of slip-resistance on lubricated surfaces, but conclusive experimental proof has been lacking. This article describes an experiment in which five pairs of shoes were soled with the same rubber compound. Four of the pairs were abraded by different grades of grit to produce a range of roughness values. The coefficient of friction (CoF) of the five solings was then measured repeatedly by the walking traction method on wet surfaces including glazed wall tiles, vinyl asbestos coated with the wax floor polish, and both sides of a sheet of float glass. The Kruskal-Wallis statistical test proved beyond doubt that the soling roughness is a major factor in determining the CoF of this rubber soling material; p < 10⁻⁵. Nearly all of the grip was due to surface roughness of the soling material on these atypically smooth floors, although the surface roughness of the floors also had a significant effect on CoF; p < 0.003. Float glass is shown to be a promising reference floor material for the measurement of CoF of footwear; there was no statistical difference between results for the two sides of the glass sheet. Float glass could be used in the development of a standard CoF test method because new sheets of glass from the same manufacturer are identical and extremely smooth. The specification of CoF values for solings/floors combinations in lubricated conditions is of little value unless associated with roughness measurements and knowledge of how wear will affect the surface roughness of the sole. This article reports the first evidence that any specification of flooring by measuring CoF based on dry surfaces could lead to an increase in the number of injuries caused by slipping on the wet surfaces. Published by Elsevier Science Ltd     

Coefficient of friction,walking speed and cadence on slippery and dry surfaces: shoes with different groove depths

Objective. The present study aimed to determine the coefficient of friction (COF), walking speed (WS) and cadence while walking on slippery and dry surfaces using shoes with different sole groove depths to predict likelihood of fall. Background. Design of shoe sole groove is crucial to prevent slipping during walking. Methods. 22 healthy young men (mean age 24.5, body mass index 22.5) volunteered for this semi-experimental study. Six different conditions of the test (combination of three shoes and two surfaces) were defined and the condition was repeated three times. In total, 396 trials (22 subjects?×?3 groove depths?×?2 surfaces?×?3 times) were obtained for data analysis. COF was recorded by force platform at 1000?Hz and walking parameters recorded using 3D motion analysis with six infrared cameras at 200?Hz. Results. The highest COF was obtained from the deepest groove depth (5.0?mm) on both dry and slippery surfaces. The COF on slippery surfaces was significantly lower in comparison with dry surfaces. WS and cadence were not significantly different on dry and slippery surfaces. Conclusion. The deeper groove is better to prevent slipping because the COF increases by increasing the shoe sole groove depth. WS did not change on dry and slippery surfaces.     

Musculoskeletal Load Assessment of the Upper Limb Positions Subjectively Chosen as the Most Convenient

Work posture is determined by interdependence between work stand design, the necessity to perform given activities, and the anthropometric dimensions of the worker, but it also depends on individual preferences. The aim of the study was to compare the musculoskeletal load of the right upper extremity under conditions of imposed (standard) upper limb position and subjectively chosen ones, and to assess the influence of the changes in magnitude of the external force on the musculoskeletal load in the examined limb positions. Ten healthy male participants took part in the study. Muscular load associated with different upper extremity positions with and without external load were assessed. Musculoskeletal load for standard and subjectively chosen limb positions and two different values of external load were compared by means of theoretical and experimental methods. Results indicate that differences in musculoskeletal load between imposed and subjectively chosen limb positions were not high enough to show statistically significant differences, and the upper limb position chosen by the participant does not always cause the lowest musculoskeletal load.     

作训鞋靴用复合抗刺穿中底的开发和应用

本文参照GB／T531．1和GB／T12017-1989对自行研制的两种抗刺穿中底、底革、钢板和市场上的织物抗刺穿中底进行了抗刺穿实验检测和对比分析。实验分析发现两种自行研制的抗刺穿中底抗刺穿力都在1,100N以上,其抗刺穿性能都达到标准要求。其中多层复合织物抗刺穿中底在抗刺穿性和舒适性以及经济性方面更加适合于作训鞋靴。最后确定了在作训鞋靴生产过程中,抗刺穿中底与鞋靴帮套的结合工艺。     

Determination of Heat Loss from the Feet and Insulation of the Footwear

This study compared the methods of determining footwear insulation on human participants and a thermal foot model. Another purpose was to find the minimal number of measurement points on the human foot that is needed for insulation calculation. A bare foot was tested at 3 ambient temperatures on 6 participants. Three types of footwear were tested on 2 participants. The mean insulation for a bare foot obtained on the participant and model were similar. The insulation of warm footwear measured by the 2 methods was also similar. For thin footwear the insulation values from the participants were higher than those from the thermal model. The differences could be related to undefined physiological factors. Two points on the foot can be enough to measure the insulation of footwear on human participants (r = .98). However, due to the big individual differences of humans, and good repeatability and simplicity of thermal foot method, the latter should be preferred for testing.