Human computer models represent a useful tool for investigating the human body response to external static/dynamic loads or for human-centred design. Articulated Total Body (ATB) models are the simplest human multibody models, where body segments are represented by ellipsoids joined at skeletal articulations. Over the years, regression models on both living subjects’ and cadavers’ data have been developed to predict body segments properties. These models are affected by two main limitations: the only inputs are the subject’s weight and height, not considering that for the same combination different morphologies can exist; secondly, regression analyses were performed over a specific population not including peculiar morphologies (under-weight or obese). A novel methodology for developing anthropomorphic ATB models is here presented: a statistical shape model able to predict the external geometry of the human body from a limited set of anthropometric measurements was implemented and body segments were obtained by segmentation; the respective inertial properties were computed from volumes, assuming a constant density value. The properties of this new anthropomorphic ATB model were compared to those calculated by GEBOD (Generator of Body Data), a well-known programme for ATB data calculation. A virtual population of twenty subjects was analysed: with reference to the inertial properties the most relevant differences occurred at the abdomen and the thighs segments (60% relative error), while the trunk, the shoulder and the calves represent the most critical areas for the geometry reconstruction (50 mm average error). The significance of these outcomes was investigated performing multibody simulations with various scenarios.@en

Nowadays, there are complications in the environments where the crutch is being used, which cause discomfort for users throughout the use and therapy period. There are many flaws in cities’ infrastructure. Using a simple search on the internet, it can be claimed that standard crutches have an array of design faults and ergonomic problems, and users seek to fix the problems with non-industrial solutions and home treatments. For this reason, various accessories for crutches are being produced, and even designers have proposed new types of crutches as replacements. However, the majority of them still didn’t pass the human-centered research procedure.

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BACKGROUND: The Quick Exposure Check (QEC) assesses four major body parts and engages users in assessing some physical interactions relevant to design in task analysis. OBJECTIVE: In this paper, we investigated the application of QEC as the ergonomic intervention to detect pre-production ergonomic design faults in the apple sorting machine by applying physical and virtual prototyping for three different tasks analysis divided into two phases (Task 1: Apple harvesting and preparation for sorting; Task 2: Sorting control and separation of waste fruits; Task 3: Transfer of separated apples). METHOD: First, the QEC questionnaire was administered while Iranian participants interacted with the machine to detect abnormal posture. Second, we redesigned a concept of the machine and assessed it with QEC by a focus group. RESULTS: Before design, the high pressure in Task 1 is on the back (dynamic), shoulder/arm, and very high pressure in Task 2, and in Task 3 on the back (static), arm/shoulder/neck, making an uncomfortable situation for posture. After redesign, we observed decreased pressures on the back/shoulder/arm in Task 1 from high to medium, in Task 3 from very high to low, and also in Task 2, this was detectable decreasing from very high pressures on the back/shoulder/arm and the high pressures on the neck to medium. CONCLUSION: Prototyping with QEC demonstrated that accurate redesigning of the machine with concentration on shifting from static tasks to dynamic or conversely, and ease of access by adjusting dimensions according to anthropometry and auxiliary products, could reduce musculoskeletal disorders.

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Feature at a Glance: Welcome to the special issue on anthropometry! This discussion will cover a range of differently sized topics to fit your interests. De Bruin and Castelluci discuss the problems of designing school furniture that fits students, noting that “Regarding School furniture dimensions, students are usually exposed to furniture with fixed dimensions, which makes it almost impossible to adjust to the ‘growing’ anthropometrics along their school life and neither does it accommodate multidimensional fit very well.” Griffin et al. discuss developing an “understanding [of] body dimensions in relation to how a body functions, moves, and changes” that “is fundamental to creating compatible wearable products” for aging women. Alemany et al. discuss 4D scanning, observing that “This technology is able to capture the human body surface in motion at high frequency with a high resolution” and offers “an enormous potential to advance in ergonomic design and biomechanics.” Bradtmiller describes the “nearly infinite combination of head/facial characteristics” and that “This combination of traits allows us to recognize unique individuals but increases the challenge of designing head and face products that fit a wide variety of individuals with a relatively small number of sizes”.

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BACKGROUND: An appropriate match between a product and its end-users requires anthropometric data, which show variations among different countries. Proper Personal Protection Equipment (PPE) fit is key for safety and comfort. Chile had no head and facial anthropometric data available in order to design face/head PPE. OBJECTIVE: To describe face/head anthropometric characteristics of Chilean workers. Additionally, this study compared those dimensions against other populations (United States (US), South Korea and China). METHODS: An anthropometric survey involving 21 measures was conducted between September 2013 to May 2016 using stratified sampling. The measurements were based on ISO/TS 16976-2 and ISO 15535 to ensure the highest standards possible, and a total of 474 workers, aged from 18 to 66 years old, participated in the survey. RESULTS: The biggest differences were in Neck circumference, Weight, Nose breadth, Nose protrusion, Bitragion chin arc, Face length, Subnasale-sellion length, Face width, Bigonial breadth and Bitragion subnasal arc. Head length of Chileans were longer than Chinese and South Korean ones, but shorter than US Head length. Chilean Head breadth is smaller than Chinese and South Korean ones. Chileans Face length was the largest observed. Face width of Chileans was smaller than US and Chinese ones. Gender specific differences were also observed in the inter-country comparisons. Chilean males had larger anthropometric dimensions than females. CONCLUSION: Chilean Head and face dimensions differed significantly when compared against US, South Korean and Chines Head and Face dimensions. Chileans have longer and narrower faces with wider mouths, with a head size in between the US and Asian heads. Face and head PPE for Chileans should use dimensions in the current paper in order to ensure proper fit.

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Anthropometry is critical for product and workplace design. Highly prevalent, office work is associated with sedentarism and physical discomfort due to prolonged sitting. Dynamic seating (alternating across sitting, perching, and standing) has been suggested as an alternative to overcome those problems. The current study tested a large sample of anthropometric data for mismatch levels against national and international office furniture standards using dynamic seating as a framework with traditional and perching mismatch equations, applied to three recommended dynamic seating components. Dimensions present in the standards used did not match the majority of the sample. For sitting, seat width and depth individually presented the lowest levels of match, as well as under cumulative fit of all office furniture dimensions. However, these were alleviated when incorporating adjustability. Perching was shown to be generally impeded given commercially-available chair height options. Limitations in state-of-the-art perching equations are discussed, and two new models are proposed as design alternatives. Further research should focus on testing the criteria presented in this research through discomfort and objective measures.

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BACKGROUND: Anthropometrics is very important when ensuring a physical match between end users and product or workstations. OBJECTIVES: The purpose of this study are twofold, to provide anthropometric data for the design of products and to examine the secular changes in the adult Chilean workers in a period of more than 20 years. METHODS: Nineteen anthropometric measurements from two samples from 1995 and 2016 were compared using independent t-test (95% confidence interval), where additionally absolute and relative differences were calculated. RESULTS: The secular trend observed for Stature is characterized by an increase average of 20mm and 10.5mm per decade for females and males, respectively. There is a positive secular trend for both genders, which is observed for most of the selected body measurements. The most pronounced increases were onWeight, Shoulder breadth, Body mass index, Popliteal height; Buttock-popliteal length and Hip width. CONCLUSIONS: Segmental dimensions that experienced a positive secular trend, together with Weight and Stature, are highly correlated with seating design, addressing the need to review products targeting Chilean adult workers, such as public transport seats, office furniture or industrial workplaces.

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Background: Grip strength is an essential component of physical fitness. The objective of this study was to develop normative handgrip strength data for Iranian healthy boys and girls comparing their handgrip strength with international reference values. Methods: Handgrip strength was measured in 2637 healthy children/adolescents (1391 boys and 1246 girls), aged 7–18 years, using a standard adjustable Jamar hand dynamometer (Model 5030 J1, Sammons Preston Rolyan, Bolingbrook, IL, USA). Body mass (kg) and stature (cm) were measured and body mass index was computed in kg/m². The sample was stratified by gender, age, and hand preference. Results: Handgrip strength increased with age and was considerably higher in boys than in girls for all age groups (p < 0.001). Grip strength had a parallel and linear growth for both genders until the age of about 11 years and showed a steeper upward slope in boys than in girls thereafter. The findings of the current investigation were significantly different from those of the previously published normative data, especially for boys over the age of 12 years and girls in the age range of 7–18 years (p < 0.001). This difference was mainly in such a way that the Iranians had lower handgrip strength. Conclusions: The differences between present results and those of similar available in the literature in this field emphasize the significant role of using normative data specific to a particular population in research or clinical settings.

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BACKGROUND: Former studies on work-related upper limb disorders (WRULD) within university education report substantial prevalence rates. In this study, developments in WRULD amongst students in the period 2004-2014 were investigated. Our findings can be a benchmark for future studies, in particular when there are major societal changes as in the case of the COVID-19 pandemic. OBJECTIVE: Differences in time (academic year), how long students have been studying (year of studying), relations with computer time and societal changes were points of interest. METHODS: 2254 students (average age 20.0 years) responded to a questionnaire on WRULD. Students experiencing complaints were further questioned about the severity of complaints and associated body locations. RESULTS: The average percentage of students experiencing complaints was 57%. The highest prevalence rates and severity scores were found in the first and last recorded academic years. The neck, shoulder, back and wrist were most often indicated. The prevalence of complaints raised from the 1st (49%) to the 4th (75%) year of studying. Two seriousness measures showed highest scores in the 5th/6th/7th year of studying. Relations were found between both the prevalence and seriousness of complaints with reported computer time. CONCLUSIONS: After an initial decreasing trend from the academic year 2006/2007 to 2010/2011 there was an increase in WRULD amongst students from 2010/2011 to 2013/2014. Limiting financial and study time factors may have played a role. Structural attention for WRULD prevention and risk factors seems to be effective in reducing prevalence and severity of WRULD. This seems to be even more necessary due to recent COVID-related changes in the students' lives.

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The use of 3D anthropometric data of children’s heads and faces has great potential in the development of protective gear and medical products that need to provide a close fit in order to function well. Given the lack of detailed data of this kind, the aim of this study is to map the size and shape variation of Dutch children’s heads and faces and investigate possible implications for the design of a ventilation mask. In this study, a dataset of heads and faces of 303 Dutch children aged six months to seven years consisting of traditional measurements and 3D scans were analysed. A principal component analysis (PCA) of facial measurements was performed to map the variation of the children’s face shapes. The first principal component describes the overall size, whilst the second principal component captures the more width related variation of the face. After establishing a homology between the 3D scanned face shapes, a second principal component analysis was done on the point coordinates, revealing the most prominent variations in 3D shape within the sample.

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Anthropometry has been used extensively for designing safe and sustainable products and workplaces. However, it is common that designers need straightforward guidelines and dimensions, which they often lack, for specific design situations. Anthropometric data are usually presented in tables that summarize percentile values, separated by gender, of a specific population, which makes it difficult for designers to generate applications for mixed populations, such as industrial settings. Using a recently collected anthropometric database of Chilean workers (male and female), international standards of dimensions for working height, depth, and ideal manual handling height are tested with univariate and bivariate methods. Alternative dimensions are presented for both adjustable and non-adjustable designs. Additionally, procedures to combine samples, and for knowing how many users match with a particular design are explained using the sample data. As expected, adjustable designs proved to match with higher numbers of users, while non-adjustable dimensions recommended by ISO presented low levels of matching. Furthermore, the non-adjustable design achieved 83% of matching, which increased to the desired levels (90%) with the inclusion of a 50 mm increase platform. Finally, the Z-Score equation proved to be a useful tool to know the percentages of the population that are matched with a particular design dimension. Relevance for the industry: Dimensions for working height, depth, and ideal manual handling heights, which are currently not available, are provided for Chilean workers. A method to determine the matching percentage in a population is explained, in order to assess matching probabilities when having only summarized anthropometric tables and the dimensions for the design itself.

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Designing products that closely interact with the human body can be quite challenging. Think for example about wearables like helmets, (Virtual Reality-) goggles, masks, garments, sports braces, or shoes. We are all unique individuals and this requires designers to carefully consider the great variety of human body shapes and come up with smart ways of accommodating this variety in such products through the use of sizing systems, adjustable parts, or flexible materials. We introduce ‘Mannequin’, a new tool for the DINED- platform. Through this tool, we want to make 3D anthropometry accessible for engineers, designers, and ergonomists by providing an intuitive interface for exploring 3D body shape variation and creating 3D design manikins. In the open data spirit of DINED, Mannequin can be freely used for both research and commercial purposes.@en

The facial fit of respirators is crucial for determining how effectively respirators may protect users from exposure to airborne contaminants, when their use is required in the workplace. In the Chilean market, all the respirators available have been designed and manufactured using foreign regulations. The aim of this research was to determine the facial dimensions in a sample of Chilean workers (users or potential users of respiratory protective equipment) and the possible mismatch between their anthropometric characteristics and the respirator fit test panels proposed by Los Alamos National Laboratory (LANL) and National Institute for Occupational Safety and Health (NIOSH). An anthropometric survey that included 11 measurements was conducted, based on ISO/TS 16976–2 and ISO 15535 to ensure the highest standards possible, and a total of 474 workers (female: 229, male: 245), aged 18–66 years old participated in the survey. The anthropometric measurements were then contrasted with the fit test panels used in LANL (for half and full facepieces) and NIOSH (Bivariate and Principal component analysis (PCA)), to verify the level of mismatch. The results showed that LANL panels presented a level of mismatch of 11.8% and 21% for the half-facepiece and the full-facepiece, respectively. Considering the NIOSH bivariate and PCA panels, 4.6% and 4.4% of the sample remains without an assigned cell, respectively. It can be concluded that the LANL panels for half and full facepieces do not match the facial dimensions of the Chilean working population. The panels developed by NIOSH and considered by the ISO/TS 16976–2 (bivariate and PCA), are applicable to the Chilean working population. Relevance for the Industry: This research provides anthropometric measurements of Chilean workers, to determine the dimensions for half- and full-facepiece respirators, which are currently not available. The NIOSH or ISO fit test panels, as opposed to LANL panels, should be used when manufacturing respirators for Chilean workers.

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A 3D head and face scan data can be usefully applied in the ergonomic design of a wearable product such as an oxygen mask or a virtual reality (VR) headset to support the safety as well as comfort for a certain amount of a target population. This study is aimed to develop analysis and design methods of an ergonomic facial wearable products (e.g., pilot oxygen mask, VR headsets) based on numerous 3D face scan data (366 faces and 2,299 heads) through the template registration and the finite element (FE) analysis methods to predict the contact pressure between the face and a product. The application of the FE analysis on numerous 3D images to find an optimal form of a product is a novel approach in product design. The proposed methods on contact pressure analysis could be usefully applied for wearable products, which fit body parts.@en

Obesity is a growing issue in western societies with consequences for the field of human centered design. Most anthropometric data sources assume the data follow the Gaussian distribution, with population data symmetrically distributed above and below the mean value. This assumption is often true in length measurements like body heights, but may not be true for measurements more sensitive to body mass, like body weight, hip width, elbow-to-elbow width, and body depth. While length measurements have remained relatively stable over time in western societies, mass related measurements are increasing. The authors have experience in providing data via an interactive website DINED, which seeks to make anthropometry accessible without requiring expert knowledge about anatomy and statistics. Currently all DINED dimensions are assumed Gaussian, including those related to body mass. This might not work when designing for plus size people. Future additions in DINED will be about design for obesity and about how to implement 3D scanning into the design process in order to redress these defects.

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Introduction There is still a need for competent breast lump detection palpation skills, especially in developing countries. Our goal is to design, develop, and establish a test to determine whether students can, by touch alone, identify and discriminate between a range of different simulated lesions at different adiposity levels. Methods Common lesions, breast cancers, and cysts were physically simulated and hidden in a test object referred to as the "tactile landscape" (TL). Ribs, intercostal muscle, and nodularity - normal anatomical features - increased their realistic complexity. Varying depths of features simulated varying degrees of adiposity. A testing protocol was created to determine the testee's ability to identify and discriminate different commonly occurring breast masses using palpation. Five experts (four breast surgeons and one general practitioner) and 20 inexperienced medical students were recruited and tested. Results were compared. Results The TL has been based on previously verified breast models and has softness similar to 53% of women's breasts and nodularity similar to 60% as assessed in a breast clinic by breast surgeons. The five experts indicated that the simulated lesions felt like those they might encounter in clinical practice and all of them identified the lesions and nonlesions hidden in the TL 100% correctly, thus indicating the value of the model. In contrast, only one student was able to identify all the lesions. One student identified none of them. The remaining students mean score was 65%. Conclusions All students but one performed poorly in comparison to the experts. This indicates that the test could be useful to test students' ability to identify and discriminate breast masses. If successful, it will add previously missing capability to the mix of assessment instruments already used, thus potentially improving clinical breast examination training and assessment.

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Chile has experienced significant improvements in its economy; thus, a secular trend in height has been observed in its population. Gender equality has also improved hand in hand with active policies addressing the gender gap in several dimensions (work, education, health) and overall economic improvement. This study examined changes in sexual height dimorphism in four samples of Chilean male and female working-age subjects and attempted to establish associations with gender equality and welfare. Sexual height dimorphism was calculated and compared with gender equality and overall welfare indicators between 1955 and 1995. Sexual height dimorphism reduction was seen to be strongly associated with greater gender equality and some general welfare indicators, such as the infant mortality rate. Gross domestic product per capita was not associated with sexual height dimorphism, but it showed significant associations with gender equality indicators. Overall, the gender gap has been reduced in Chile, which can be observed through improvements in gender equality indicators and a reduction in height dimorphism, mainly in areas associated with women's health. However, gender equality is still far behind in terms of female labour participation and women in political power, which require attention and further improvements.

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In Ergonomic product design, designers need to translate anthropometric data of the target population into product dimensions or sizing systems. Currently, sizing systems are often based on traditional anthropometric data and generally use the variation of one or two key body dimensions directly related to the product. For products that need to closely fit a certain part of the body it is relevant to incorporate multiple key dimensions. This can be realized by a multivariate approach such as a Principal Component Analysis. Over the past decades, there has been an increase in incorporating 3D imaging in anthropometric surveys. In order to integrate the use of 3D anthropometry in product sizing, representative models are used to visualize the variability of the target population. For the development of a ventilation mask for children, this study compares representative models of 3D faces based on a bivariate, multivariate and shape based analysis of 303 children's faces.@en

3D body scanning has been used broadly including digital human modeling, simulation, ergonomic product design, and so forth. This research used template-registered faces of 336 Koreans in order to use them to design an oxygen mask that provides good fit to Korean faces. The finite element analysis method is applied onto the template-registered faces to predict the contact pressure of a mask design onto different faces. The average and variation of the estimated contact pressure values among all the Korean faces were analyzed for evaluation of the appropriateness of a mask design for Koreans. The proposed method can be usefully applied to find an optimal shape of wearable products for a specific target population.

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