A cluster-based law enforcement body armor sizing system: Concept, procedure, and design practice.

Given the evolution of human body dimensions, the increasing diversity within the law enforcement workforce, the growing risks of assault faced by law enforcement officers (LEOs), and the absence of a national standard for body armor sizing, there is a critical need to explore LEO body size classification. This exploration will facilitate the development of an armor sizing structure that adequately accommodates the current LEO population. This study aimed to address this need by developing a LEO body armor sizing scheme and creating a sizing chart/app. Additionally, a plan was devised for a series of 'sizing vests' that would enhance LEO armor accommodation and facilitate fit assessment. Torso anthropometric data pertaining to body armor sizing were collected from 756 male and 218 female LEOs across different regions of the United States. Based on the collected data, a nine-size system for male LEOs and an eight-size scheme for female LEOs were suggested. Furthermore, a sizing chart/app was proposed to enable LEOs to swiftly identify an armor size that is most likely to fit an individual, considering a few anthropometric characteristics known to LEOs. To supplement the sizing chart/app, a series of 'sizing vests' were recommended. These vests would provide LEOs with a physical means to assess and determine the best-fitting armor size, offering an alternative to relying solely on the sizing chart/app. We recommend that armor manufacturers adopt these new sizing systems and create prototypes of armor that can be evaluated within this sizing structure. This evaluation process will facilitate improved fit and enhanced protection for LEOs.

Needs and Procedures for a National Anthropometry Study of Law Enforcement Officers.

OBJECTIVES: This research aims to determine the need and extent for a national anthropometry survey of law enforcement officers (LEOs) via an exploratory investigation of anthropometric changes of LEOs in four decades and comparisons of the LEO data with three existing military and civilian anthropometry sources. BACKGROUND: The best available anthropometric dataset of LEOs is 45 years old and has largely become outdated due to demographic changes. Assessing the extent of anthropometric changes of LEOs through a sample and evaluating the differences of the sample against existing anthropometric datasets is a step toward ascertaining the necessity for a national LEO anthropometry study. METHOD: Thirty-two body dimensions of 67 regional male LEOs and seven female LEOs were measured, and the data of males were compared with the best available LEO anthropometry data from 1975 and three recent non-LEO anthropometry databases. RESULTS: Anthropometric dimensions were significantly different between this LEO study and existing data sources, especially in chest circumference and body weight. Most of the significant differences are important differences for LEO protective gear and vehicle design. CONCLUSION: The study confirmed that the existing 45-year-old LEO dataset and recent Army and civilian datasets would not be suitable for armor and equipment design for the current LEO population. APPLICATION: The study results are useful in supporting the decision of investing in a national LEO anthropometry survey and for equipment manufacturers to recognize the distinctiveness of LEO anthropometry from other populations and the magnitude of anthropometry changes of LEOs over the past 45 years.

Design for All - Design for Disabled: How important is anthropometry?

BACKGROUND: Design for All or Universal Design is a relatively new domain in Ergonomics. With globally ageing populations, it has however recently gained significant interest. OBJECTIVE: This position paper summarizes the outcomes of a workshop held at the virtual 21st Triennial Congress of the International Ergonomics Association. The paper expands the horizon of traditional Ergonomics into a domain where people are differently abled and establishes a platform for the essential needs of future ergonomic standards which are required to inform inclusive design guidelines, or Design for All, extending the range of users. METHODS: The paper includes contributions from Asian, Australian, European and US workshop participants who are accessibility design experts in their respective geographic regions. The paper summarizes issues related to anthropometry in the Design for All, based on recent work in the US (Access board) and actual developments in various national and international accessibility standardization bodies, such as the Standards Australia/Standards New Zealand, the European Standardization Organization (EN 17210:2021; EN 17161:2019) and the International Organization for Standardization (ISO 21542:2021 and BS ISO 7176-5:2008). CONCLUSIONS: The paper concludes that despite the identification of a significant gap in knowledge of the anthropometry of people with disabilities as far back as 1990, work towards bridging the gap and enabling ergonomic standardization has not progressed since then globally. The lack of standardization in anthropometric data on people with a physical disability continues to complicate provision of data for mobility and accessibility design and hampers accessibility standardization efforts.

Encumbered and Traditional Anthropometry of Law Enforcement Officers for Vehicle Workspace and Protective Equipment Design.

OBJECTIVES: This study investigated anthropometric changes of national law enforcement officers (LEOs) in 46 years, compared the differences between LEO data and civilian anthropometry, and identified the magnitude of differences in dimensions measured with gear versus semi-nude measurements. BACKGROUND: The best available 46-year-old anthropometric dataset of LEOs has largely become outdated due to demographic changes. Additionally, anthropometric data of female LEOs and LEO measurements with gear are lacking. METHOD: Thirty-four traditional body dimensions and 15 with gear measurements of 756 male and 218 female LEOs were collected through a stratified national survey using a data collection trailer that traveled across the U.S. and the data were compared to the LEO anthropometric data from 1975 and existing civilian anthropometric databases. RESULTS: LEO body size and shape have evolved over the past 46 years - an increase of 12.2 kg in body weight, 90 mm in chest circumference, and 120 mm in waist circumference for men. No previous data was available for comparison for females. Compared to civilians, both male and female LEOs have a larger upper body build. LEO gear added 91 mm in waist breadth for men and 120 mm for women, and 11 kg in weight for men and 9 kg for women. CONCLUSION: The study reveals that equipment design based on the existing civilian datasets or 46-year-old LEO dataset would not accommodate the current LEO population. The new data fill this gap. Application: The differences reported above are important for LEO body gear, vehicle console, and vehicle ingress/egress design.

Analysis of hand-forearm anthropometric components in assessing handgrip and pinch strengths of school-aged children and adolescents: a partial least squares (PLS) approach.

BACKGROUND: The purpose of this study was to examine the influence of hand-forearm anthropometric dimensions on handgrip and pinch strengths among 7-18 years children and adolescents and to investigate the extent to which these variables can be used to predict hand strength. METHODS: Four types of hand strengths including handgrip, tip to tip, key, and three-jaw chuck pinches were measured in 2637 healthy children and adolescents (1391 boys and 1246 girls) aged 7-18 years using standard adjustable Jamar hydraulic hand dynamometer and pinch gauge. A set of 17 hand-forearm anthropometric dimensions were also measured with an accurate digital caliper and tape measure. RESULTS: No significant differences were found between the hand strengths of boys and girls up to the age of 10 years. Gender related differences in handgrip and pinches were observed from the age of 11 years onwards, with boys always being stronger. The dominant hand was stronger than the non-dominant hand (8% for handgrip and by about 10% for all three types of pinches). The strongest correlations were found between the hand length and hand strengths (r > 0.83 for handgrip and three all pinches; p < 0.001, 2-tailed). Based on the partial least squares (PLS) analysis, 8 out of 17 anthropometric indices including hand length, hand circumference, thumb length, index finger length, middle finger length, and forearm length had considerable loadings in the PLS analysis, which together accounted for 46% of the total variance. CONCLUSIONS: These results may be used by health professionals in clinical settings as well as by designers to create ergonomic hand tools.

Anthropometric Dimensions of Individuals With High Body Mass Index.

OBJECTIVE: This study presents anthropometric data for individuals with high body mass index (BMI). Modified anthropometric dimensions were also developed to address the challenges of obtaining accurate and repeatable data for this population segment. BACKGROUND: The prevalence of obesity affects approximately 40% of the U.S. adult population. Anthropometric data are needed to guide product design and safety, but few individuals with high BMI have been measured in available datasets. METHOD: Anthropometric data for a convenience sample of 288 adults with high BMI (≥30 kg/m2) were collected. To increase participation and minimize participant discomfort, measurements were collected at three bariatric weight loss clinics and one academic research institution. RESULTS: The current obese cohort are heavier than the U.S. general population, with a difference in mean body weight of 47 kg for women and 56 kg for men. The obese cohort are also heavier and have a higher BMI compared with the NIOSH (National Institute for Occupational Safety and Health) truck driver population. Waist circumferential measures of the current obese cohort were larger than women or men in either population compared, a result indicative of meaningful body shape differences. CONCLUSION: To our knowledge, this study is the first to collect anthropometric data for the obese population segment and conduct comparisons to the U.S. general population and available occupational databases. The obese cohort differed substantially with respect to the distributions of anthropometric variables. APPLICATION: These data provide insights about the obese population segment that are relevant to product design, and establish a foundation for future data collection efforts.

U.S. truck driver anthropometric study and multivariate anthropometric models for cab designs.

OBJECTIVE: This study presents data from a large-scale anthropometric study of U.S. truck drivers and the multivariate anthropometric models developed for the design of next-generation truck cabs. BACKGROUND: Up-to-date anthropometric information of the U.S. truck driver population is needed for the design of safe and ergonomically efficient truck cabs. METHOD: We collected 35 anthropometric dimensions for 1,950 truck drivers (1,779 males and 171 females) across the continental United States using a sampling plan designed to capture the appropriate ethnic, gender, and age distributions of the truck driver population. RESULTS: Truck drivers are heavier than the U.S.general population, with a difference in mean body weight of 13.5 kg for males and 15.4 kg for females. They are also different in physique from the U.S. general population. In addition, the current truck drivers are heavier and different in physique compared to their counterparts of 25 to 30 years ago. CONCLUSION: The data obtained in this study provide more accurate anthropometric information for cab designs than do the current U.S. general population data or truck driver data collected 25 to 30 years ago. Multivariate anthropometric models, spanning 95% of the current truck driver population on the basis of a set of 12 anthropometric measurements, have been developed to facilitate future cab designs. APPLICATION: The up-to-date truck driver anthropometric data and multivariate anthropometric models will benefit the design of future truck cabs which, in turn, will help promote the safety and health of the U.S. truck drivers.

A protocol for evaluating the accuracy of 3D body scanners.

Scan-derived landmarks locations and surface shapes are more and more used, but there is no commonly accepted protocol for evaluating the accuracy of these measurements. Therefore we propose a protocol for evaluating the accuracy of surface shape and the repeatability of scan-derived landmark locations. According to existing Japanese and German domestic standards, we propose to use an artefact (e.g. sphere with diameter of about 120 mm) calibrated very accurately for evaluating the accuracy of scanner-systems. For evaluating the repeatability of landmark locations, we propose to use an anthropomorphic dummy with landmark locations premarked. These test objects are measured by a 3D body scanner to be evaluated. Evaluation parameters such as trueness, precision, and repeatability are calculated from the measured data. A round-robin test was conducted in six different institutes using 17 body/head/foot scanners produced by eight companies. The purposes of the roundrobin test were to evaluate the availability of test objects to different body scanners, and to examine the measurement locations of test objects and quality parameters to be reported. As a result, the proposed test objects could be measured and the data exported by all scanner systems except one, which could not export the ball measurement. For a comparative purpose, a figure of measured surface might be useful.

Anthropometric change: implications for office ergonomics.

Well-designed office workspaces require good anthropometric data in order to accommodate variability in the worker population. The recent obesity epidemic carries with it a number of anthropometric changes that have significant impact on design. We examine anthropometric change among US civilians over the last 50 years, and then examine that change in a subset of the US population--the US military--as military data sets often have more ergonomic dimensions than civilian ones. The civilian mean stature increased throughout the period 1962 to 2006 for both males and females. However, the rate of increase in mean weight was considerably faster. As a result, the male obesity rate changed from 10.7% in 1962 to 31.3% in 2006. The female change for the same period was 15.8% to 33.2%. In the Army, the proportion of obesity increased from 3.6% to 20.9%, in males. In the absence of national US ergonomic data, we demonstrate one approach to tracking civilian change in these dimensions, applying military height/weight regression equations to the civilian population estimates. This approach is useful for population monitoring but is not suitable for establishing new design limits, as regression estimates likely underestimate the change at the ends of the distribution.

Development of sizing structure for fall arrest harness design.

Updated harness designs are needed to accommodate diverse populations in the current workforce. This paper determined an improved fall-arrest harness sizing scheme and strap-length configurations for harness design. A 3-D elliptic Fourier analysis (EFA) procedure with 123 coefficients was developed to quantify torso-shape effect on harness fit, based on 3-D data of 108 women and 108 men. The EFA coefficients were then applied to 600 representative body scans from a national database of 2382 participants to establish an improved sizing system. Study outcomes suggested a more upward back D-ring location for women than current unisex designs to accommodate female torso form and mitigate their fit problem. Results also suggested an improved system of three sizes for women and three sizes for men. New harness sizing charts for women and men were proposed accordingly. Using the most current 3-D whole-body digital scanning technology, this study assembled data from a US workforce to establish an improved fall-arrest harness sizing system and strap configurations for men and women. The information is useful for new generation harness designs to reduce the risk of worker injury.

New respirator fit test panels representing the current U.S. civilian work force.

The fit test panels currently used for respirator research, design, and certification are 25-subject panels developed by Los Alamos National Laboratory (LANL) and are based on data from the 1967 and 1968 anthropometric surveys of U.S. Air Force personnel. Military data do not represent the great diversity in face size and shape seen in civilian populations. In addition, the demographics of the U.S. population have changed over the last 30 years. Thus, it is necessary to assess and refine the LANL fit test panels. This paper presents the development of new respirator fit test panels representative of current U.S. civilian workers based on an anthropometric survey of 3,997 respirator users conducted in 2003. One panel was developed using face length and face width (bivariate approach) and weighting subjects to match the age and race distribution of the U.S. population as determined from the 2000 census. Another panel was developed using the first two principal components obtained from a set of 10 facial dimensions (age and race adjusted). These 10 dimensions are associated with respirator fit and leakage and can predict the remaining face dimensions well. Respirators designed to fit these panels are expected to accommodate more than 95% of the current U.S. civilian workers. Both panels are more representative of the U.S. population than the existing LANL panel and may be appropriate for testing both half-masks and full-face piece respirators. Respirator manufacturers, standards development organizations, and government respirator certification bodies need to select the appropriate fit test panel for their particular needs. The bivariate panel is simpler to use than the principal component analysis (PCA) panel and is most similar to the LANL panel currently used. The inclusion of the eight additional facial measurements allows the PCA panel to provide better criteria for excluding extreme face sizes from being used. Because the boundaries of the two new panels are significantly different from the LANL panel, it may be necessary to develop new respirator sizing systems. A new five-category sizing system is proposed.

Head-and-face anthropometric survey of U.S. respirator users.

Sizing data generated by the military for use in fitting respirators have been the normative basis for commercial respirator sizing. Anthropometric data developed for males and females of military age in the 1950s and 1960s are still in use today and form the only comprehensive body of information available on this subject. The twofold objective of this study was to: (1) develop an anthropometric database detailing the face size distributions of respirator users using both traditional measurement methods and three-dimensional scanning systems; and (2) use the database to establish fit test panels to be incorporated into the National Institute for Occupational Safety and Health's respirator certification and international standards. A stratified sampling plan was used with three age strata, two gender strata, and four race/ethnic group strata. The plan called for an equal sample size of 166 in each cell. Subjects were obtained at 41 sites from 8 states. In addition to height and weight, 18 facial dimensions and neck circumferences were measured using traditional methods. A total of 3997 subjects were measured using traditional methods, and 1013 of them were also scanned using a 3-D head scanner. As this was a volunteer sample, subjects did not appear in the specific proportions needed for the sampling plan. The resulting data were weighted to correspond to the U.S. population. This article presents the summary statistics for the traditional measurement data only. Multivariate analyses of the data from this study and military data revealed that using historical, military data would be inadequate for describing the anthropometric variability of the current U.S. work force.

Sizing and fit of fall-protection harnesses.

Full-body fall-protection harnesses have been a critical work-practice control technology for reducing the number of fall-related injuries and fatalities among construction workers; yet, very little is known about the fit of these harnesses to the population that wears them. This study evaluated the fit and sizing efficacy of a harness system. Seventy-two male and 26 female construction workers participated in the study. Their body size-and-shape information was measured while they were suspended (with a harness) and standing (with and without a harness), using a 3-D full-body laser scanner and traditional anthropometric calipers. Fisher's discriminant analysis results did not point to the need for a change in the current sizing selection scheme by body height and weight for end users. However, an integrated redesign of harness components is needed because 40% of subjects did not pass fit-performance criteria in either the standing or suspended condition. A multivariate accommodation analysis has identified 15 representative body models for the 'standard-size' harness design. These models can serve as a useful population to test harness design until a larger survey of the nation's construction workers can be done. Finally, further developments in 3-D shape quantification methods are recommended to improve the harness design process; the point-to-point anthropometric information currently used seems to be insufficient for harness design.

Interobserver error in a large scale anthropometric survey.

The adverse effects of interobserver error on morphometric population comparisons are well documented in the literature. While interobserver error can rarely be avoided, it can be minimized by having a single individual locate and mark relevant landmarks, by limiting the number of observers for each variable, and by reviewing repeated measures data daily to catch and correct measurer drift during data collection. In this study, two pairs of experts participated in interobserver error trials designed to pre-set observer error limits for use in the quality control of a large scale anthropometric survey. Repeatability data were also collected twice daily in the field and reviewed with the measurers. Interobserver errors obtained in the field were lower than those achieved by the experts for 27 of 30 dimensions. These results suggest that establishment of permissible interobserver error in advance of data collection and frequent review of repeated measurements during data collection can reduce the magnitude of interobserver error below that obtained by experts measuring in a laboratory setting. However, even differences of small magnitude can be serios when they are directional, and 17 of 30 dimensions exhibited statistically significant bias between measurers despite all quality control efforts. The magnitudes of interobserver error observed in this study have proven particularly useful in evaluating the biological relevance of statistically significant differences which are of relatively small magnitude.