Table 1 - uploaded by K. Blake Mitchell
Content may be subject to copyright.
Source publication
This document outlines the methodology used to collect data in an evaluation examining the range of motion (ROM) of 115 Soldiers and Airmen conducted by the Natick Soldier Research, Development and Engineering Center in 2011. The purpose of the evaluation was to better understand the performance impact of body armor on U.S. military warfighters. Tr...
Similar publications
This study focuses on the effect of body armor fit on Warfighter mobility as measured by range of motion. Forty male active duty military personnel participated in the study with four different body armor configurations: Baseline, Initial Fit, Increased and Decreased sizes. The results indicated that the degradations in the Decreased and Initial Fi...
Citations
... This includes testing how well the armor provides protection and coverage when the wearer is running, crouching, or kneeling. 90,91 Environmental testing ...
This paper highlights a comprehensive review of the design, performance, and ergonomics of women’s body armor. Body armor is an essential part of defending people in high-risk areas, such as law enforcement officers, military personnel, and security employees. Traditional body armor, however, has typically been designed with male users in mind, ignoring the anatomical and physiological variations between men and women. This review intends to draw attention to the problems with women’s body armor and offer information on new developments made to solve these problems. It addresses several topics, including anatomical and physiological differences, challenges and limitations of traditional female body armor, materials used for female body armor, design considerations for female body armor, performance evaluation, and future directions and recommendations.
... However, PPE often introduces an ergonomic, human systems integration, and mass burden to the wearer [10]. Use of body armour systems and firefighter turnout gear, for example, have been quantitatively shown to negatively impact ROM and dynamic task performance [11][12][13][14][15]. Working in hot and humid conditions while wearing PPE has also been shown to place additional physiological stress on the body that impacts cognition and comfort, ultimately leading to fatigue, decreased performance, and injury [9,16,17]. ...
... Dynamic fit is important to assess in the context of occupation specific tasks, as the aim of the equipment item should be to minimize restrictions on mobility, and associated fatigue, metabolic cost, performance, and injury detriments. Commonly, dynamic fit is assessed through the use of ROM and functional task performance, including occupationally relevant tasks [13,18,[110][111][112] with standardised ROM tasks and procedures having been developed for some equipment items, such as body armour [15]. These tasks typically compare encumbered and non-encumbered conditions to establish a baseline for performance measures. ...
Objective
To explore the effect of personal protective equipment (PPE) fit on functional performance across a range of occupational domains.
Background
PPE introduces an ergonomic, human systems integration, and mass burden to the wearer, and these factors are thought to be amplified if PPE is ill-fitting. However, few studies have considered the role of fit (static, dynamic, and cognitive) when evaluating PPE-related performance detriments in occupational settings.
Method
A systematic literature review was conducted to identify relevant studies, which were then critically appraised based on methodological quality and collated to compare key findings and present evidence-based recommendations for future research directions across a range of occupational domains.
Results
16 published studies met the inclusion criteria, 88% of which found that the fit of PPE had a statistically significant effect on occupational performance. Poorly sized PPE resulted in slower or increased reaction time; decreased range of motion or mobility; decreased endurance or tolerance; decreased pulmonary function; and altered muscle activation. Limited research met the inclusion criteria and those that did had risks of bias in methodology quality.
Conclusion
Future research evaluating the effect of PPE on performance in occupational settings should aim to recruit a more representative population; consider sex as a covariate; quantify and evaluate PPE fit and performance when integrated with all relevant equipment items; include outcome measures related to all three categories of fit (static, dynamic, cognitive); and assess performance of operationally relevant tasks.
... Research has identified that as the weight and composition of body armour increases, a subsequent decrease in ROM in single-and multi-joint movements (militaryspecific and non-military movements) occur (e.g. movements at the shoulder and hip joints) (Glass and Ross 2015;Mitchell 2013). It is essential to screen and determine the impairment of ROM around the shoulder, hip, and knee to evaluate military personnel's mobility and flag potential decreases in physical performance or injury risks that may arise while wearing body armour (Coltman et al. 2021). ...
... The opposite occurs in extension; the leg moves away from the camera, making it hard to track the leg in real-time, like shoulder extension. Body armour can restrict hip flexion up to 5% in a high knee test (Mitchell 2013), which may explain the greater reliability in both BA conditions compared to the NBA condition. The restriction potentially allowed the limb to hit a fixed-range each time throughout the flexion task, which may have led to similar ROM values achieved. ...
The HumanTrak captures human movement through markerless motion tracking and can be a crucial tool in military physical screening. Reliability was examined in eighteen healthy participants who completed shoulder and hip ROM, and dynamic tasks in three body armour conditions. Generally, for all conditions, good to excellent reliability was observed in shoulder abduction and flexion, hip abduction and adduction, and dynamic squats knee and hip flexion (ICC ≥ 0.75 excluding outliers). Shoulder adduction and hip flexion demonstrated moderate to excellent reliability (ICC ≥ 0.50). Shoulder and hip extension and the drop jump were unreliable (ICC: 0.10–0.94, 0.15–0.89, and 0.30–0.82, respectively) due to the large distribution of ICC scores. Tasks with ROM values ≥ 100° involving movement towards or perpendicular to the HumanTrak camera tended to have greater reliability than movements moving away from the camera and out of the perpendicular plane regardless if body armour was worn.
Practitioner summary: The HumanTrak analyses ROM in a time-efficient manner in a military setting. This study established that shoulder abduction and adduction (no body armour) and shoulder, hip, and knee flexion were the most reliable measurement for all conditions. Further work is required for movements across different planes.
Abbreviations: ROM: range of motion; NBA: no body armour; BA: unloaded body armour; BA9: body armour with 9 kg; RGB: red, green, blue; ICC: intra-class correlation; SEM: standard error of measurement; MDC: minimal detectable change: MSE: mean square error; r: pearson correlations; N: sample size
... An experiment to measure the mobility degradation with varied coverage would be one way to find out what the interaction of mobility degradation relative to coverage variation is. Choi et al. (2017) measured standardized range of motion (ROM) measurements (from Mitchell, 2013) in four test configurations (predicted size, one size smaller, one size larger, and no plate) per test participant (TP) to investigate width and length variations of the torso plate. Cross Body Extension (Seated) was measured to assess the impact of the plate width on mobility, and Trunk Flexion (Seated) to assess plate length. ...
The development of optimized fitting body armor is critical to the fightability and protection of our warfighters and first responders. Body armor systems generally worn by warfighters consists of three protective portions: rigid plates, a soft armor insert, and a carrier/vest. Rigid plates are inserted into the front, back, and sides of the body armor to provide a higher level of protection for the wearer, while the soft armor is positioned behind the plates and in areas of the body where a lower level of protection is acceptable or required for mobility and comfort. Previously, a comprehensive fit mapping study on the family of armor plates to investigate the relationship between the coverage, anthropometry and mobility relative to size specifications of torso and side plates was conducted (Choi et. al., 2017). There is a delicate tradeoff between covering more (i.e., a greater area of protection) while not degrading the wearer’s mission performance (primarily their mobility). However, some level of mobility degradation is unavoidable. Choi et. al. (2017)'s results quantitatively defined the impact of coverage on mobility, visualized the mobility degradation as coverage increase, and set the allowable mobility degradation to be 10%. The coverage corresponding to the allowable mobility degradation was then converted into anthropometric dimensions. Accommodation envelopes for the current U.S. Army torso plates, relative to the male and female US Army population, were reported. Final size tariffs were calculated using the front plate. A sizing system for the back plate and/or side plates were not developed.This current study explores a theoretical framework for ballistic rigid plate size optimization for the front, back and side plates. When the protection coverage is maximized with minimal mobility degradation, the system would be considered optimized. For this study, minimal mobility degradation was set to 10%. For the front plate, Choi et. al. was revisited to retrieve the maximum width and length while limiting the mobility degradation to 10%. Chest Breadth, was measured using the ANSUR II (Gordon et. al., 2014) procedure, and Suprasternale -Tenth Rib Length was used to derive the width and length of plates, respectively. Then, a specification of the front ballistic plate, given anthropometric characteristics of the current U.S. Army population was developed from a reverse engineering approach. Theoretical accommodation envelopes for each front plate size were then developed and plotted against the current ANSUR II data. Once the front plate sizing system was developed, anthropometric characteristics of cases within each accommodation envelope per size were investigated to develop the required size specifications for the back plate. The width of the back plate shares the width of the matching front plate, but the length takes into account the back length, from the Cervicale -Tenth Rib Length. Size specifications for the side plates were also developed. Given that the front and back plates are worn together; the maximum width of the side plate is defined by the surface availability at the location of the tenth rib level. The side plate length is defined using the distance between Tenth Rib and the Axilla. A theoretical size system for a family of rigid armor plates is presented in a series of tables as well as bivariate plots. A detailed process for plate size prediction and the interaction between the front, back and side plates is presented.
... iometer; 6) Arm cross reach (ACR); Participants were seated and reached with their left and right arm individually over the other shoulder while keeping the elbow horizontal, measured in cm; both arms. The range of motion tests were partly selected and adapted from the standard methodology for assessment of range of motion while wearing body armor (B. Mitchell, 2013). ...
Background
Soldiers are required to conduct tasks and operations in physically demanding situations, where the ability to move (mobility) quickly is important to lethality and survivability.
This study employed a specially designed suit to try to isolate the main mass property characteristics of personal protective clothing/equipment (PPCE) including mass, bulk and stiffness as much as possible and evaluated their effects on soldier performance across operationally-relevant mobility tasks.
Method
Eight male military subjects performed the load effects assessment program (LEAP) obstacle course while wearing 7 different configurations of specifically designed suit: unencumbered (control), 10 kg mass, 30 kg mass, 20 L bulk, medium stiffness, high stiffness and a mixed configuration consisting of 10 kg mass, 20 L bulk and medium stiffness. The primary outcome measure was total LEAP completion time. Additionally, heart rate, rating of perceived exertion (RPE), range of motion and vertical jump heights were measured and related to LEAP performance.
Results
All configurations degraded or tended to degrade the total LEAP completion times (p-value < 0.05), except for the medium stiffness configuration. Heart rate did not differ significantly between configurations, while RPE scores of configurations 30 kg and mix were significantly higher compared to control (p < 0.01).
Conclusion
Mass, bulk and stiffness all negatively influence LEAP obstacle performance. Therefore, all three have to be considered when trying to reduce the physical burden on soldiers.
... Joint-specific and functional ROM restrictions are quantified with standard anthropometric equipment for body-borne armor systems Jones et al., 2014;Mitchell, 2013), and with 3D motion capture (Hu et al., 2007;Reid et al., 2014) and inertial measurement units (Bertrand et al., 2014;Di Capua & Akin, 2012;Fineman et al., 2018) for spacesuits. Similar strategies of using anthropometric body scans and inertial sensors have also been used for assessing firefighter gear, such as investigating static fit on dynamic fit for fire boots and turnout suits (McQuerry, 2020;Park et al., , 2019. ...
Objective
To define static, dynamic, and cognitive fit and their interactions as they pertain to exosystems and to document open research needs in using these fit characteristics to inform exosystem design.
Background
Initial exosystem sizing and fit evaluations are currently based on scalar anthropometric dimensions and subjective assessments. As fit depends on ongoing interactions related to task setting and user, attempts to tailor equipment have limitations when optimizing for this limited fit definition.
Method
A targeted literature review was conducted to inform a conceptual framework defining three characteristics of exosystem fit: static, dynamic, and cognitive. Details are provided on the importance of differentiating fit characteristics for developing exosystems.
Results
Static fit considers alignment between human and equipment and requires understanding anthropometric characteristics of target users and geometric equipment features. Dynamic fit assesses how the human and equipment move and interact with each other, with a focus on the relative alignment between the two systems. Cognitive fit considers the stages of human-information processing, including somatosensation, executive function, and motor selection. Human cognitive capabilities should remain available to process task- and stimulus-related information in the presence of an exosystem. Dynamic and cognitive fit are operationalized in a task-specific manner, while static fit can be considered for predefined postures.
Conclusion
A deeper understanding of how an exosystem fits an individual is needed to ensure good human–system performance. Development of methods for evaluating different fit characteristics is necessary.
Application
Methods are presented to inform exosystem evaluation across physical and cognitive characteristics.
... Body armor systems provide essential ballistic protection for military personnel. However, it has been documented that body armor, a type of protective equipment, can also interfere with a Warfighters' mobility [1]. The immediate changes identified from wearing protective equipment on the Warfighter include an increase in bulk and reduced mobility related to the equipment [2,3]. ...
... Standardized encumbered range of motion (ROM) measurements [1] were used to help quantify a Warfighter's mobility in this study. ROM is a quantitative and controlled measurement of individual joint movements in a single plane of motion, focusing on the major joints, in this case the shoulders, hips, and spine; all areas covered by the body armor systems. ...
... There does appear to be an impact on mobility, when measured by ROM measures relative to the addition of body armor [1,3], and therefore, further analysis was performed to investigate the impact of body armor fit on mobility. The delta values, between each body armor configuration and the Baseline, were calculated and used to represent the actual amount of impact from the fit of the body armor on mobility. ...
This study focuses on the effect of body armor fit on Warfighter mobility as measured by range of motion. Forty male active duty military personnel participated in the study with four different body armor configurations: Baseline, Initial Fit, Increased and Decreased sizes. The results indicated that the degradations in the Decreased and Initial Fit sizes were always statistically equivalent to each other, however, mobility in the Increased size were further degraded; 5° for the extension and rotation movements on average and up to 1 inch for flexion and reach. More importantly, across all the movements while wearing an Increased size further degraded mobility by 2.4% on average relative to the Decreased or Initial fit size. Therefore, when evaluated by ROM measurements, there was no benefit to wearing a smaller body armor size to improve mobility relative to the Initial Fit size, but there was a penalty wearing an Increased size.
... It is therefore necessary to evaluate protective systems to ensure that mobility is not compromised to the point where mission performance is degraded to an unacceptable level, thereby increasing Soldier vulnerabilities. Numerous studies have investigated the range of motion of minimally clad individuals (Boone and Azen, 1979;Gaidosik and Bohannon, 1987), and two preliminary studies were conducted in 2010 (Mitchell, 2013) assessing the impact of body armor alone on Soldier range of motion; however, only very minimal work has been completed on individuals in full military CIE. ...
... It is therefore necessary to evaluate protective systems to ensure that mobility is not compromised to the point where mission performance is degraded to an unacceptable level, thereby increasing Soldier vulnerabilities. Numerous studies have investigated the range of motion of minimally clad individuals (Boone and Azen, 1979;Gaidosik and Bohannon, 1987), and a preliminary study was conducted in 2010 (Mitchell, 2013) assessing the impact of body armor alone on Soldier range of motion; however, only very minimal work has been completed on individuals in full military CIE. ...
While much work has been done to detail the physical anthropometry and range of motion ranges of the semi-nude or lightly clothed individual, limited information and data currently exists characterizing the space and movement claims of the encumbered dismounted Soldier. Soldiers are required to wear multiple layers of clothing and protective equipment in addition to mission essential gear. In order to document and measure impacts on space claims/bulk and mobility, 32 active duty, male Soldiers were measured in four loaded configurations; two duty positions (rifleman and grenadier) were
represented in two different body armor systems (plate carrier and vest, where the vest had a larger area of coverage).
Across the four loaded conditions, increases in size (59-101%) were evident in addition to increases in weight (13-23 kg). These corresponded to decreases in mobility, measured via range of motion. Soldiers typically saw their range of motion degrade between 6-27° for the goniometer measurements and 25-159 mm for the majority of the reach measurements. Larger increases in bulk and decreases in mobility were seen in the body armor system with the increased area of coverage. Additionally, larger increases in bulk and decreases in mobility were seen for the grenadier than for the rifleman duty position. Because much of the bulk was added around the waist, movements that involved bending at the waist (e.g., Trunk Flexion Standing and Sitting) had the largest degradations from the Baseline (duty uniform only).
... The results from this study indicate there is a thermal benefit wearing this prototype integrated concealable body armor system versus the currently fielded modular design outer-armor system. Future studies should be conducted to assess other human factors and performance elements (mobility, range of motion, etc.) [12][13] that could influence energy costs and metabolic heat production associated to wear of each ensemble [14]. Human research testing should always be a critical step in the development and fielding process; however, importance and value of biophysical testing and mathematical modeling should not be overlooked. ...
Concealable body armor and integrated protective clothing systems are of interest for both law enforcement and the military. Ballistic body armor systems are highly protective; however, these systems impose a significant thermal burden. PURPOSE: The purpose of this study was to compare the total mass, biophysical characteristics, and imposed thermal burden associated with a concealable armor shirt and a currently used outer-armor vest for the US Army. METHODS: The thermal resistance (R ct , clo) and evaporative resistances (R et , i m) were measured using a sweating thermal manikin within a climate-controlled wind tunnel to American Society for Testing and Materials (ASTM) standards. Using a biophysics-based thermoregulatory model, predictions of rise in core body temperature were made for a walking pace of 1.34 ms-1 (3 mph), in three simulated environments (air temperature (°C), relative humidity (%), wind velocity (ms-1)): hot humid (35°C, 75%, 1 ms-1), hot dry (49°C, 20%, 1 ms-1), and temperate (35°C, 50%, 1 ms-1). RESULTS: The total mass of the concealable armor shirt ensemble and current outer-armor vest ensemble weighed approximately the same (16.9 and 17 kg respectively), resulting in similar predicted metabolic costs of walking. The concealable armor shirt had a higher thermal resistance than the outer-armor vest (1.9 vs 1.63 clo); while the concealable armor shirt ensemble's vapor permeability was higher than the outer-armor vest (0.45 vs 0.35 i m). Modeling showed the concealable armor-shirt ensemble performed better in each of the three simulated environmental conditions, with a slower rate of rise in core body temperature compared to the outer-armor vest ensemble. CONCLUSION: Modeling and simulation suggest the concealable armor shirt ensemble reduces thermal strain imposed on individual wearers.
... Work from Dorman and Havenith [31] found that increases in energy costs while wearing protective clothing were not entirely associated with mass, suggesting there are significant ergonomic factors such as hobbling or unfavorable causes of increased energy demands. The modeling approach presented here does not address the ergonomic aspects of each of the BA configurations (e.g., form, fit), nor the potential biomechanical effects associated with wearing different BA configurations (e.g., hobbling, decreased range of motion) [32][33]. However, relatively simple adjustments to predictions could be made to represent increases in metabolic costs due to improper form or fit where assumed. ...
Introduction: Military personnel are often required to wear ballistic protection in order to defend against
enemies. However, this added protection increases mass carried and imposes additional
thermal burden on the individual. Body armor (BA) is known to reduce combat casualties,
but the effects of BA mass and insulation on the physical performance of soldiers are less
well documented. Until recently, the emphasis has been increasing personal protection,
with little consideration of the adverse impacts on human performance.
Objective: The purpose of this work was to use sweating thermal manikin and mathematical modeling
techniques to quantify the tradeoff between increased BA protection, the accompanying
mass, and thermal effects on human performance.
Methods: Using a sweating thermal manikin, total insulation (IT, clo) and vapor permeability indexes
(im) were measured for a baseline clothing ensemble with and without one of seven increasingly
protective U.S. Army BA configurations. Using mathematical modeling, predictions
were made of thermal impact on humans wearing each configuration while working in hot/
dry (desert), hot/humid (jungle), and temperate environmental conditions.
Results: In nearly still air (0.4 m/s), IT ranged from 1.57 to 1.63 clo and im from 0.35 to 0.42 for the
seven BA conditions, compared to IT and im values of 1.37 clo and 0.45 respectively, for the
baseline condition (no BA).
Conclusion: Biophysical assessments and predictive modeling show a quantifiable relationship exists
among increased protection and increased thermal burden and decreased work capacity.
