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Development of the DoD Body Composition Estimation Equations
Abstract
This report summarizes the research findings that led to the policy decisions for development of the body fat content screening procedures and equations that are currently under consideration for inclusion in the Department of Defense (DoD) Instruction (DoDI) 1308.3, Physical Fitness and Body Fat Programs. After reviewing research results, a DoD ad hoc working group recommended that a tiered body fat content standard be adopted. A weight-for-height screen would be adopted based on the recommendations of the Healthy People 2000 Committee: Healthy weights are represented by body mass index (BMI) values between 19 and 25, irrespective of gender. Service members exceeding the weight-for-height standards would have their body fat content determined using equations currently in use by the Navy and Air Force.
... and is publicly available for less than $15 (12). The LS app uses touch screen technology to identify circumferences of the neck, waist, abdomen, and hips on frontal and sagittal view photographs and predict %BF using regression equations developed by the Department of Defense (DoD) to predict body composition of military personnel (6,18). The validity and reliability of estimates of %BF using the LS app have yet to be established. ...
... All circumferences were taken sequentially, then repeated a second and third time. The three measurements were averaged, then rounded according to instructions provided by the DoD (18) and used in the following gender-specific DoD equations (6,18) to estimate %BF. where height and circumference measurements are in inches. ...
... Using the photograph from the right lateral view, the administrator marked the anterior and posterior borders of the neck below the larynx and perpendicular to the long axis of the neck, abdomen, waist, and hips. The LS app displays the predicted %BF values calculated from the equation developed by the DoD to predict %BF from manually measured circumferences (6,18). ...
Purpose:
The purpose of this study was to determine the validity and reliability of the LeanScreen (LS) mobile application that estimates percent body fat (%BF) using estimates of circumferences from photographs.
Methods:
The %BF of 148 weight-stable adults was estimated once using DXA. Each of two administrators assessed the %BF of each subject twice using the LS app and manually measured circumferences. A mixed model ANOVA and Bland-Altman analyses were used to compare the estimates of %BF obtained from each method. Inter- and intrarater reliability was determined using multiple measurements taken by each of two administrators.
Results:
The LS app and manually measured circumferences significantly underestimated (p < 0.05) the %BF determined by DXA by an average of -3.26 and -4.82 %BF, respectively. The LS app (6.99 %BF) and manually measured circumferences (6.76 %BF) had large limits of agreement. All inter- and intrarater reliability coefficients of estimates of %BF using the LS app and manually measured circumferences exceeded 0.99.
Conclusions:
The estimates of %BF from manually measured circumferences and the LS app were highly reliable. However, these field measures are not recommended for the assessment of body composition due to significant bias and large limits of agreements.
... )−70.041×log10(height)+36.76. 5 Reproducibility of this estimate between experienced observers is±1% BF units. 5 Body composition was assessed by dual-energy X-ray absorptiometry (DXA) (iDXA, GE Healthcare, Madison, Wisconsin, USA) and data analysis relied on manufacturer-supplied algorithms (enCORE, V.13.5, Lunar, Madison,Wisconsin, USA). ...
... )−70.041×log10(height)+36.76. 5 Reproducibility of this estimate between experienced observers is±1% BF units. 5 Body composition was assessed by dual-energy X-ray absorptiometry (DXA) (iDXA, GE Healthcare, Madison, Wisconsin, USA) and data analysis relied on manufacturer-supplied algorithms (enCORE, V.13.5, Lunar, Madison,Wisconsin, USA). 6 7 DXA-determined mass matched gravimetric measures for participants with the highest DXA %BF and overestimated scale weight by 2 kg for the two lowest DXA %BF men, not explained by deviations in hydration of the assumed fat-free mass (FFM). ...
Background
The creation of highly muscled and strong fighters is a recurring theme in human performance enhancement concepts. Physical readiness standards, intended to prevent obesity in the military, produce contradictory objectives, hounding large individuals to lose weight because of confusion between body size and body composition. Through selection, specialised training and policy exceptions the US Marine Corps has successfully developed a unique group of large (body mass index (BMI) >30 kg/m ² ) and strong individuals, the body bearers (BB) who carry coffins of Marines to their final resting place.
Methods
We examined the relationship between adiposity and body size from nine male BB (age 25.0±2.1, height: 1.84±0.04 (1.80–1.92) m, BMI: 33.0±2.1 (30–37) kg/m ² ). Body composition was assessed by dual-energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA) and tape measured abdominal circumference (AC)-based equations and from three-dimensional scanning (3DS).
Results
Measures were made of fat-free mass (FFM): 90.5±7.0 (82.0–106.7) kg, where FFM included total body water: 62.8±5.0 (55.8–71.8) L, representing 69±2 (67–73) % of FFM, along with calculated FFM index: 26.8±2.4 (24.4–32.9) kg/m ² ). DXA measures were made for bone mineral content 4.1±0.4 (3.5–4.9) kg, bone mineral density (BMD) 1.56±0.10 (1.37–1.76) g/cm ² and %BF 19.5±6.6 (9.0–27.8). Additional measures of percent body fat (%BF) were made by AC: 20.3±2.9 (15.2–24.6), BIA: 23.7±6.4 (9.8–29.2) and 3DS: 25.5±4.7 (18.9–32.2). AC %BF reasonably matched DXA %BF, with expected overprediction and underprediction at low and high DXA %BF. BIA %BF was affected by deviations from assumed FFM hydration (72%–73%).
Conclusion
These men are classified as obese by BMI but carried massive amounts of muscle and bone on their large frames, while presenting a range of %BF irrelevant to strength performance. BMI did not predict obesity and adiposity had no association with muscle mass and strength performance.
... In vivo coefficient of variation for soft tissue and %BF DXA is 0.4% to 1.0% (11). Manual circumference measurements at the neck, waist, and hips were made in triplicate using a calibrated fiberglass tape measure and recorded to the nearest 0.1 cm to estimate %BF CIRC using the Hodgdon equation for women (12); this is the DoD standard for female body composition measurement (10). Body physique was captured via three-dimensional (3D) infrared scanner (SS20 Scanner; Size Stream, Cary, NC) (13), which produced automated circumference measurements at the neck, shoulder, chest, bicep, forearm, waist, wrist, buttocks (equates to manual hip measure), thigh, calf, and ankle were obtained from each scan for comparison to manual measures. ...
... The emphasis on strength training reported by the FEW participants is reflected in the summary of body physique in Figure 1 and the differences in body region circumferences compared with mean values for Army women in the ANSUR database (19). This difference from typical female Soldier physique (e.g., greater circumferences at the neck and buttocks than average ANSUR female Soldier) may account for the significant overestimation of body fat by the Army circumference-based body fat estimation equation (Table 1) as compared with body fat by DXA (10,12). Increases in body size and muscularity have been well documented for male athletes in team sports over the past decades and similar shifts may be expected for females as more women engage in sport and train accordingly, just as may be happening with more military women training for physically demanding combat arms roles (38,39). ...
Introduction:
This study characterized a sample of the first women to complete elite United States (US) military training.
Methods:
Twelve female graduates of the US Army Ranger Course and one of the first Marine Corps Infantry Officers Course graduates participated in three days of laboratory testing including serum endocrine profiles, aerobic capacity, standing broad jump (SBJ), common soldiering tasks, Army Combat Fitness Test (ACFT), and body composition (DXA, 3D body surface scans, and anthropometry).
Results:
The women were 6 mo to 4 y post-course graduation, 30 ± 6 y (mean ± SD), height 1.67 ± 0.07 m, body mass 69.4 ± 8.2 kg, BMI 25.0 ± 2.3 kg·m-2. DXA relative fat was 20.0 ± 2.0%; fat-free mass (FFM) 53.0 ± 5.9 kg; fat-free mass index (FFMI) 20.0 ± 1.7 kg·m-2; bone mineral content 2.75 ± 0.28 kg; bone mineral density 1.24 ± 0.07 g·cm-2; aerobic capacity 48.2 ± 4.8 mL·kg-1·min-1; total ACFT score 505 ± 27; SBJ 2.0 ± 0.2 m; 123 kg casualty drag 0.70 ± 0.20 m·s-1, and 4 mile 47 kg ruck march 64 ± 6 min. All women were within normal healthy female range for circulating androgens. Physique from 3D scan demonstrated greater circumferences at eight out of the eleven sites compared to the standard military female.
Conclusions:
These pioneering women possessed high strength and aerobic capacity, low %BF; high FFM, FFMI, and bone mass and density; and they were not virilized based on endocrine measures as compared to other reference groups. This group is larger in body size and leaner than the average Army woman. These elite physical performers seem most comparable to female competitive strength athletes.
... These were developed against a sample of male and female sailors and validated against a large sample of male and female soldiers from the 1984 Army Body Composition Study (Hodgdon and Beckett, 1984a;Hodgdon and Beckett, 1984b;Fitzgerald et al., 1986). The Hodgdon equations are an integral part of the US Department of Defense body composition standards today (Hodgdon and Friedl, 1999). ...
... Stature and body mass were obtained with calibrated stadiometer and electronic floor scale (Seca, Chino, CA (Hodgdon and Beckett, 1984a;Hodgdon and Beckett, 1984b). Reproducibility of this estimate between experienced observers is ±1% body fat units (Hodgdon and Friedl, 1999). Body composition was assessed by DXA (iDXA, GE Healthcare, Madison, WI) and data analysis relied on manufacturer supplied algorithms (Encore, version 13.5, Lunar Corp., Madison, WI) (Mazess et al., 1990;Toombs et al., 2012;Lukaski, 2017). ...
Purpose: Body composition assessment methods are dependent on their underlying principles, and assumptions of each method may be affected by age and sex. This study compared an abdominal circumference-focused method of percent body fat estimation (AC %BF) to a criterion method of dual-energy x-ray absorptiometry (DXA), and a comparative assessment with bioelectrical impedance (BIA), in younger (≤30 years) and older (>age 30 years) physically fit (meeting/exceeding annual US Marine Corps fitness testing requirements) men and women.
Methods: Fit healthy US Marines (430 men, 179 women; 18–57 years) were assessed for body composition by DXA (iDXA, GE Lunar), anthropometry, and BIA (Quantum IV, RJL Systems).
Results: Compared to DXA %BF, male AC %BF underestimated for both ≤30 and >30 years age groups (bias, -2.6 ± 3.7 and -2.5 ± 3.7%); while female AC %BF overestimated for both ≤30 and >30 years age groups (2.3 ± 4.3 and 1.3 ± 4.8%). On an individual basis, lean men and women were overestimated and higher %BF individuals were underestimated. Predictions from BIA were more accurate and reflected less relationship to adiposity for each age and sex group (males: ≤30, 0.4 ± 3.2, >30 years, -0.5 ± 3.5; women: ≤30, 1.4 ± 3.1, >30 years, 0.0 ± 3.3). Total body water (hydration) and bone mineral content (BMC) as a proportion of fat-free mass (FFM) remained consistent across the age range; however, women had a higher proportion of %BMC/FFM than men. Older men and women (>age 30 years) were larger and carried more fat but had similar FFM compared to younger men and women.
Conclusion: The AC %BF provides a field expedient method for the US Marine Corps to classify individuals for obesity prevention, but does not provide research-grade quantitative body composition data.
... The development of field expedient assessments came from large Navy and Army data collection efforts, with crossvalidation of a range of techniques and equations on each data set. 161 Bioelectrical impedance and other technologically sophisticated techniques were too inconsistent for individual standards testing, and ultimately, the simplest circumference-based equations developed by the Navy were determined to be the best. 162 Waist circumferenceebased body fat standards are an important part of military readiness standards today, and failure to meet the standard can result in discharge from the military. ...
... 162 Waist circumferenceebased body fat standards are an important part of military readiness standards today, and failure to meet the standard can result in discharge from the military. 161 Only Japan has a comparable standard applied across a large population, using mandatory waist circumferences in men and women over age 50 in an effort to stem the rising tide of type 2 diabetes and other obesity-related diseases. The evolution and science of military body composition standards are reviewed elsewhere. ...
Nutrition science in the United States has been shaped by national security needs, specifically the need to feed armies to sustain their performance in the face of adversity. In the 20th century, Army nutrition research provided foundational data on metabolic requirements of healthy men and women, developed important methodologies for laboratory and field nutrition surveys, and led national efforts on performance in extreme environments. The study of human metabolism in challenging environments has proven to be an enduring need for the Army, and this requires unique capabilities with embedded soldier-scientists conducting credible studies in relevant field environments. Support for military nutrition research periodically surged during the 20th century, including reincarnations in the 1940 and 1980s when nutritional physiologists were colocated with food developers. Major findings repeatedly centered on the challenges of inadequate energy intakes in all extreme environments rather than identifying any unique needs for specific ration components.
... Note: In a cross validation of the equations, the Navy equations for men and women were superior based on standard error of the estimate, mean difference, and correlation coefficients, compared to the criterion method of hydrostatic weighing (Hodgdon 1992). The DoD equation currently in use is based on the Navy equations and provides %body fat estimates from English units (Hodgdon and Friedl 1999). Circumference measurements and height are in cm; abdomen I is measured in women at the thinnest part of the waist, usually about midway between the edge of the sternum and the umbilicus; abdomen II is measured at the umbilicus; thigh circumference is taken in women at the upper end of the thigh, just below the gluteal fold; FFM = fat-free mass; density is converted with the Siri equation (Siri 1961). ...
... The equations were validated with additional samples of men (n = 100) and women (n = 146) and also later validated on the Army sample collected for the development of the Army equations. The equations have been subsequently retested and validated even against a four-compartment model method (Hodgdon and Friedl 1999). The anthropometric equations developed by the Navy for men and women were later adopted for use by all military services as the single most practical and valid method (Figure 13.3) (U.S. ...
... Body fat percentage (%BF) was derived from body circumference measurements (made in cm) according to the US Navy formula [%BF = 86.010 × log10 (abdomen -neck) -70.041 × log10 (height) + 30.30)] [12,13]. Once recruited, participants were instructed to avoid alcohol beverages, smoking, caffeine, large meals, ointments, cosmetics and showering for 4 hours before the assessment. ...
Background:
Divers thermal status influences susceptibility to decompression sickness hence the need for proper insulation during immersion in cold water. However, there is a lack of data on thermal protection provided by diving suits, hence this study.
Materials and methods:
Two different groups of divers wearing either a wetsuit (n = 15) or a dry suit (n = 15) volunteered for this study. Anthropometric data and dive experience were recorded; skin temperatures at the cervical-supraclavicular (C-SC) area and hands were assessed through high-resolution thermal infrared imaging taken pre- and post-dive.
Results:
As far as anthropometrics, pre-dive C-SC temperatures (37.0 ± 0.4°C), depth (dry: 43 ± 4.6 mfw vs. wet: 40.3 ± 4.0 mfw) and water temperature exposure (4.3°C) are concerned, both groups were comparable. Total dive time was slightly longer for dry suit divers (39.6 ± 4.0 min vs. 36.5 ± 4.1 min, p = 0.049). Post-dive, C-SC temperature was increased in dry suit divers by 0.6 ± 0.6°C, and significantly decreased in wetsuit divers by 0.8 ± 0.6°C. The difference between groups was highly significant (dry: 37.5 ± 0.7°C vs. wet: 36.2 ± 0.7°C, p = 0.004). Hand's temperature decreased significantly in both groups (dry: 30.3 ± 1.2°C vs. wet: 29.8 ± 0.8°C, p = 0.33). Difference between groups was not significant.
Conclusions:
Medium-duration immersion in cold water (< 5°C), of healthy and fully protected subjects was well tolerated. It was demonstrated that proper insulation based on a three-layer strategy allows maintaining or even slightly improve thermal balance. However, from an operational point of view, skin extremities are not preserved.
... Although anthropometric BF% estimates are rudimentary in comparison with many modern laboratory techniques, their simplicity and ease of implementation may contribute to their utility in some contexts (70) . The DoD BF% equations, which utilise two or three simple circumference estimates and height as input variables, have been a longstanding component of health and fitness assessments in the United States military (25,48,71) . Originally developed using hydrodensitometry as a criterion method, the DoD equations were subsequently revalidated using other methods, including multi-component models (25) . ...
This study reports the validity of body fat percentage (BF%) estimates from several commonly employed techniques as compared to a 5-component (5C) model criterion. Healthy adults (n=170) were assessed by dual-energy x-ray absorptiometry (DXA), air displacement plethysmography (ADP), multiple bioimpedance techniques, and optical scanning. Output was also used to produce a criterion 5C model, multiple variants of 3- and 4-component models (3C; 4C), and anthropometry-based BF% estimates. Linear regression, Bland-Altman analysis, and equivalence testing were performed alongside evaluation of the constant error (CE), total error (TE), standard error of the estimate (SEE), and coefficient of determination (R2). The major findings were: 1) Differences between 5C, 4C, and 3C models utilizing the same body volume (BV) and total body water (TBW) estimates are negligible (CE≤0.2%; SEE<0.5%; TE≤0.5%; R2=1.00; 95% limits of agreement [LOA]≤0.9%); 2) Moderate errors from alternate TBW or BV estimates in multi-component models were observed (CE≤1.3%; SEE≤2.1%; TE≤2.2%; R2≥0.95; 95% LOA≤4.2%); 3) Small differences between alternate DXA (i.e., tissue vs. region) and ADP (i.e., Siri vs. Brozek equations) estimates were observed, and both techniques generally performed well (CE<3.0%; SEE≤2.3%; TE≤3.6%; R2≥0.88; 95% LOA≤4.8%); 4) Bioimpedance technologies performed well but exhibited larger individual-level errors (CE<1.0%; SEE≤3.1%; TE≤3.3%; R2≥0.94; 95% LOA≤6.2%); and 5) Anthropometric equations generally performed poorly (CE:0.6 to 5.7%; SEE≤5.1%; TE≤7.4%; R2≥0.67; 95% LOA≤10.6%). Collectively, the data presented in this manuscript can aid researchers and clinicians in selecting an appropriate body composition assessment method and understanding the associated errors when compared to a reference multi-component model.
El presente libro no es uno más de todos aquellos textos que en modo detallado y gran precisión explican las diferentes técnicas para la evaluación antropométrica nutricional o cineantropométrica deportiva, es el modo de llenar un vacío procedimental para los que se inician en los estudios antropométricos nutricionales, al colocar a su disposición indicadores e índices, así como sus alcances e interpretación, que favorezcan el análisis en la valoración del Estado Nutricional, durante su formación pre-profesional, en el ejercicio de la profesión o en el desarrollo de investigaciones asociadas a esta temática.
No es un libro para dar cumplimiento a los objetivos de un programa de asignatura, es un texto de apoyo para lograrlo, es el impulso para que cada estudiante o profesional defina su propio modo de actuación al realizar valoraciones de la composición, complexión, proporcionalidad y linealidad corporal, con definición de operaciones que pueden ser referenciadas y contrastadas con investigaciones pasadas, presentes y futuras, definidas dentro del alcance de la antropometría, eje central de esta obra.
El cuerpo central del libro es un compendio de ecuaciones, que a manera de índices y desde el uso de variables antropométricas, permiten identificar la condición nutricia del organismo. Su volumen puede abrumar al lector, no se pretende que usen todas, solo están a su disposición para desde la objetividad que se proponen, las herramientas de medición a su disposición, los referentes a utilizar como elemento de comparación e incluso la popularidad científica del momento, haga uso de ellas en el establecimiento de su propio organigrama de trabajo.
Para facilitar la selección, se incluyen observaciones a cada una de las variables, ecuaciones o fórmulas, de tal manera que al ser elegidas se tenga presente la utilidad de las mismas en la valoración de individuos pertenecientes a diferentes grupos etáreos, su fiabilidad e incluso su posible combinación con otras mediciones. De modo adicional y en cada caso, incluye la referencia bibliográfica fuente de obtención de las mismas, de este modo se facilita su seguimiento para un lector interesado en profundizar en las raíces noseológicas de las mismas.
Como parte del libro se agregan procederes de análisis vigentes en el estudio de las proporcionalidades corporales, la composición corporal y la determinación del somatotipo, la construcción de somatocartas y la estrategia Phantom, ampliamente referenciados en investigaciones con resultados loables, estos se dirigen a todos aquellos que buscan algo más de aplicabilidad para la caracterización antropométrica de sujetos y poblaciones, de modo particular en deportistas, la pretensión es facilitar el uso y estimular la búsqueda de información, además de extender la aplicación de tales métodos a través del estímulo al interés personal, siempre bajo el supuesto que el conocimiento no es estático, su relatividad temporal requiere de cultores para su desarrollo y son los que favorecen el acercamiento a la verdad científica.
En este punto es necesario reforzar una idea antes vertida, es el interesado en esta área de saberes quien decide y conforma su estrategia de trabajo, sus procederes para el uso de las ecuaciones que le brinden más información y faciliten contrastar la misma con resultados anteriores desde una postura crítica y cautelosa, no obstante para facilitar su elección y decisiones, en la obra se incluyen ejemplos declarados en artículos de investigación que les pueden ser útiles al lector.
Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings in Nordic countries for greater energy efficiency, this study focused on human subjects´ thermal sensation, thermal comfort, thermal acceptability, draft acceptability and perceived air quality when three low temperature heating systems were used: conventional radiator, ventilation radiator or floor heating with exhaust ventilation. Human subject tests were carried out in the climate chamber at the Technical University of Denmark. In total, 24 human subjects, 12 females and 12 males participated in the tests during the winter season. The results show that no significant differences in thermal sensation and thermal comfort between the three heating systems. Ventilation radiator promised a comfortable indoor environment with a decreased water supply temperature and floor heating with exhaust ventilation can provide a basic thermal comfort level. Thermal acceptability and draft acceptability show variations in different heating systems. Gender has significant influences on thermal sensation, draft acceptability and preference of clo values. Personal thermal preference is observed between male and female. The male prefer to dress lighter than the female but both can get the same thermal comfort level. It is concluded that low temperature heating systems using exhaust air ventilation are a potentially solution when buildings are being retrofitted for improved energy efficiency and comfort of the occupants.
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