Leather and Footwear Journal

Volume 22, no 1

Contents
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COMPARISON AND ASSESSMENT OF SELECTED PARAMETERS OF CHROME-FREE AND CHROME-TANNED LEATHER
- Pages 3-16
  Elżbieta BIELAK*, Gabriela ZIELIŃSKA
  - Department of Non-Food Product Quality and Safety, Institute of Quality and Product Management Sciences, Cracow University of Economics, 27 Rakowicka St., Cracow 31-510, Poland, bielake@uek.krakow.pl, zielinsg@uek.krakow.pl
  ABSTRACT. In the leather tanning industry, decision-makers act resolutely to eliminate chrome as a tanning agent due to its negative effect on human health and the natural environment. Considering this, it makes sense to research opportunities to use chrome-free leather as a substitute for chrome-tanned leather. This paper demonstrates research on the mechanical and hygienic properties of leather tanned with glutaraldehyde as well as chrome-tanned leather, intended for shoe uppers. The results of the tensile strength and percentage extension measurements made by the Instron tensile machine, and the results of water vapour permeability measurements made by a moisture analyser, have been analysed using Statistica. The statistical data analysis has been performed using the following tests: Kolmogorov-Smirnov with Lilliefors correction, Shapiro-Wilk, T, Levene, Brown and Forsythe, Fisher-Snedecor, and Cochran-Cox. Regarding mechanical parameters, no statistically significant difference has been observed between chrome-free and chrome-tanned leather in dry conditions. However, such differences have been observed in wet samples. The tests showed higher stability of mechanical parameters of leather tanned with modified glutaraldehyde compared to chrome-tanned leather. Leather tanned with a chrome tanning agent, tested in both dry and wet conditions, showed significant differences between them, considering their tensile strength and percentage extension. The hygienic properties of both types of leather being researched are more or less similar – the research has not found any statistically significant differences for water vapour permeability.
  
  KEY WORDS: chrome-free leather, chrome-tanned leather, glutaraldehyde, leather quality
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DOES INSOLE HARDNESS AFFECT THE DYNAMIC POSTURAL STABILITY OF BASKETBALL ATHLETES DURING JUMP LANDING?
- Pages 17-24
  Yunqi TANG¹, Xinyu GUO², Xiuxing WANG², Lei QIN², Lingqiu ZOU¹, Lingjun LI¹, Yong WANG³, Hua LU⁴, Cui ZHANG^{5, 6}
  - ¹College of Art & Design, Shaanxi University of Science & Technology, Xi’an 710021, China, tangunqi@sust.edu.cn, 201012015@sust.edu.cn, 1910026@sust.edu.cn, 201012003@sust.edu.cn
  - ²Institute of Quartermaster Engineering & Technology, Systems Engineering Institute, Academy of Military Sciences (AMS), Beijing 100010, China, wangxx818@qq.com, qinlei33@126.com
  - ³Department of Physical Education, Liaocheng University, Liaocheng 252059, China, bihai_zhixin@163.com
  - ⁴China Leather Industry Association, Beijing 100044, China, lhlh0628@163.com
  - ⁵Sports Biomechanics Lab, Shandong Institute of Sports Science, Jinan 250102, China
  - ⁶Graduate School, Shandong Sport University, Jinan 250102, China, zhangcui@sdpei.edu.cn
  ABSTRACT. This study aimed to examine the effects of shoe insole hardness on the dynamic postural stability of basketball athletes during jump landing manoeuvres. Twenty college basketball athletes were recruited to complete a single-leg jump landing task on a force plate in three insole conditions (soft-, rigid- and no-insole). Kistler force plate and Pedar-X insole system were used to collect the ground reaction force (GRF) and plantar pressure data. Dynamic Postural Stability Index (DPSI), Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Vertical Stability Index (VSI) were then calculated from GRF data. DPSI, APSI, MLSI, and VSI were statistically conducted among the three insole conditions by a one-way ANOVA with repeated measures. MLSI were decreased when wearing soft- and rigid insoles compared with no-insole condition (p < 0.05). However, there were no significant differences in APSI and VSI among the three insole conditions. In the midfoot region, contact areas were increased in the soft- and rigid insole than the no-insole condition (p < 0.0001). Dynamic balance of basketball athletes in the medial-lateral direction could be enhanced by wearing insoles during jump landings tasks. However, the postural stability of basketball athletes did not increase with insole hardness increasing.
  
  KEY WORDS: dynamic postural stability; jump landing; insole hardness; ankle injury
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PLANTAR FOOTPRINTS AND 3D FOOT SHAPE DIGITAL ANALYSIS FOR OVERWEIGHT TEENAGER – ONE CASE STUDY
- Pages 25-32
  Mariana COSTEA, Arina SEUL, Aura MIHAI*
  - “Gheorghe Asachi” Technical University of Iasi, Faculty of Industrial Design and Business Management, 28 Mangeron, 700050, Iasi, Romania, mariana.costea@academic.tuiasi.ro, arina.seul@academic.tuiasi.ro, aura.mihai@academic.tuiasi.ro
  ABSTRACT. Nowadays, one of the most critical health problems among young people is obesity. Because teenagers are still in the growing process, the foot shape and plantar footprints are very important to be analysed and potential problems to be identified. Young adulthood is a risky period for the development of obesity. This study aims to analyse the plantar footprints, the biomechanical parameters obtained through plantar pressure measurements, and the 3D shape of the foot and anthropometrical parameters obtained from scanning. By comparing the results, both feet have been demonstrated to be high arched, as well as high pressures were identified and differences from left to the right foot. With these results, prophylactic footwear and components can be designed, adapted to the subject’s feet.
  
  KEY WORDS: plantar pressure, Body Mass Index, anthropometrical measurements
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RESEARCH ON FOOT ANTHROPOMETRY OF MEN WITH DIABETES IN VIETNAM
- Pages 33-44
  Van-Huan BUI^{1, *},Thi-Kien-Chung CAO², Hai-Thanh NGUYEN¹, Duy-Nam PHAN¹, Thanh-Xuan LE¹
  - ¹School of Textile – Leather and Fashion, Hanoi University of Science and Technology, No. 1, Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam
  - ²Faculty of Garment Technology and Fashion Design, Hung Yen University of Technology and Education, Dan Tien, Khoai Chau, Hung Yen, Vietnam
  ABSTRACT. Diabetes often causes foot complications, inducing diabetic patients to use therapy shoes or custom-made shoes designed on the basis of anthropometric characteristics of their feet to ensure a good fitting. Wearing poorly fitted shoes contributes to the development of foot ulcer sites. This paper presents the results of foot anthropometric research, developing a foot size system for men with diabetes in Vietnam in order to develop pressure-offloading footwear. The foot data of 212 men with type-2 diabetes aged 44 to 75 years were collected during this study. Foot photography and patient interviews about foot complications were also conducted by research assistants. The results show that the average disease duration of the surveyed patients was statistically calculated as 6.8 ± 4.3 years. The patients from 50 to 70 years old accounted for up to 86.8% of all interviewees. In all participants, the patients with foot pain and swelling of metatarsal joints accounted for 19.8%, foot ulcers accounted for 6.4%, dry feet, cracked skin, and calluses almost equally accounted for 12%. Most of the feet are slightly deformed mainly in the metatarsal joint area and no patient had a leg amputation. The patients suffering from two types of foot injuries account for more than 43.1%. Interestingly, the ball width and circumference of the patient’s foot are 4.5 mm and 6.5 mm larger than that of a healthy man’s foot, respectively; whereas, the mid-foot height is 3.7 mm lower. From the collected data and statistic figures, the patient foot sizing system has been developed including 5 sizes by length (231.5, 238.0, 244.5, 251.0, 257.5 mm), and each size by length is divided into 3 sizes by width. Our categorizing system meets more than 81.5% of the shoe size needed by men with diabetes in Vietnam.
  
  KEY WORDS: diabetic foot, foot anthropometry, foot ulcers
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POLYMER COMPOSITE BASED ON NBR RUBBER COMPOUNDED WITH RUBBER WASTE FUNCTIONALIZED WITH POTASSIUM OLEATE
- Pages 45-52
  Mihaela NIŢUICĂ (VÎLSAN), Maria Daniela STELESCU, Maria SÖNMEZ, Laurenția ALEXANDRESCU, Mihai GEORGESCU, Dana GURĂU, Mirela PANTAZI-BĂJENARU
  - INCDTP - Division Leather and Footwear Research Institute, 93 Ion Minulescu St., sector 3, Bucharest, mihaela.nituica@icpi.ro, mihaelavilsan@yahoo.com
  ABSTRACT. Waste is a material that occurs as a result of a biological or technological process that can no longer be used as such. Recycling and reusing waste make it possible to contribute to environmental protection and, of course, to the protection of human health by eliminating toxins during waste incineration. The purpose of this paper is to process and characterize polymer composites based on NBR rubber (butadiene-co-acrylonitrile rubber) and rubber waste functionalized with potassium oleate in terms of rheological characteristics (to determine the optimal vulcanization time), Brabender diagrams and physico-mechanical properties in normal state and after accelerated ageing at 70°C, for 168 h (using elastomer-specific equipment). Functionalized rubber waste (with potassium oleate up to 20% at 60°C) is introduced into the mixture in proportions of 10; 20; 30; 50%. The polymeric composites based on butadiene-co-acrylonitrile elastomer and rubber waste (ground with a cryogenic mill at 10,000 rpm, at the size of 0.35 mm) were compounded on a mixer with a capacity of 350 cm3 according to the working recipes. The mixtures were supplemented with vulcanization activators and accelerators on an electric roller, resulting in formulations in the form of 4 mm thick sheets, which are then subjected to the relevant characterizations according to the standards in force for the footwear industry.
  
  KEY WORDS: NBR rubber, rubber waste, compounding, vulcanization, polymer composite
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