Development and cross-validation of a circumference-based predictive equation to estimate body fat in an active population.

Objective: The U.S. Army uses sex-specific circumference-based prediction equations to estimate percent body fat (%BF) to evaluate adherence to body composition standards.

Physiology of Health and Performance: Enabling Success of Women in Combat Arms Roles.

Introduction: The modern female soldier has yet to be fully characterized as she steps up to fill new combat roles that have only recently been opened to women. Both U.S.

Using a Contemporary Portable Metabolic Gas Exchange System for Assessing Energy Expenditure: A Validity and Reliability Study.

There are several methods available to assess energy expenditure, all associated with inherent pros and cons that must be adequately considered for use in specific environments and populations. A requirement of all methods is that they must be valid and reliable in their capability to accurately measure oxygen consumption (VO) and carbon dioxide production (VCO). The purpose of this study was to evaluate the reliability and validity of the mobile CO/O Breath and Respiration Analyzer (COBRA) relative to a criterion system (Parvomedics TrueOne 2400, PARVO) with additional measurements to compare the COBRA to a portable system (Vyaire Medical, Oxycon Mobile, OXY).

The Fecal Metabolome Links Diet Composition, Foacidic positive ion conditions, chromatographicallyod Processing, and the Gut Microbiota to Gastrointestinal Health in a Randomized Trial of Adults Consuming a Processed Diet.

Background: Food processing alters diet digestibility and composition, thereby influencing interactions between host biology, diet, and the gut microbiota. The fecal metabolome offers insight into those relations by providing a readout of diet-microbiota interactions impacting host health.

Objectives: The aims were to determine the effects of consuming a processed diet on the fecal metabolome and to explore relations between changes in the fecal metabolome with fecal microbiota composition and gastrointestinal health markers.

In vitro gut microbiome response to carbohydrate supplementation is acutely affected by a sudden change in diet.

Background: Interactions between diet, stress and the gut microbiome are of interest as a means to modulate health and performance. Here, in vitro fermentation was used to explore the effects of a sudden change in diet, 21 days sole sustenance on the Meal, Ready-to-Eat (MRE) U.S.

Testosterone status following short-term, severe energy deficit is associated with fat-free mass loss in U.S. Marines.

The objective of this study was to determine metabolic and physiological differences between males with low testosterone (LT) versus those with normal testosterone (NT) following a period of severe energy deficit. In this secondary analysis, 68 male US Marines (mean ± SD, 24.6 ± 2.

Individual-level permethrin exposure biomarkers in U.S. army soldiers: comparison of two treatment formulations for military uniforms.

Background: Evidence suggests that wearing permethrin-treated military uniforms is not associated with current adverse health conditions. However, exposure through this route results in permethrin biomarker concentrations considerably higher than those in the U.S.

Physical and Physiological Characterization of Female Elite Warfighters.

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 3 d of laboratory testing including serum endocrine profiles, aerobic capacity, standing broad jump, common soldiering tasks, Army Combat Fitness Test, and body composition (dual-energy x-ray absorptiometry, three-dimensional body surface scans, and anthropometry).

Results: The women were 6 months to 4 yr postcourse graduation, 30 ± 6 yr (mean ± SD); height, 1.

Stress and the gut-brain axis: Cognitive performance, mood state, and biomarkers of blood-brain barrier and intestinal permeability following severe physical and psychological stress.

Background: Physical and psychological stress alter gut-brain axis activity, potentially causing intestinal barrier dysfunction that may, in turn, induce cognitive and mood impairments through exacerbated inflammation and blood brain barrier (BBB) permeability. These interactions are commonly studied in animals or artificial laboratory environments. However, military survival training provides an alternative and unique human model for studying the impacts of severe physical and psychological stress on the gut-brain axis in a realistic environment.

The Rise of the Female Warfighter: Physiology, Performance, and Future Directions.

Since 1948, the United States military has been open to both men and women as permanent party service members. However, in the majority of the time since, there have been a subset of military occupational specialties (MOS), or job descriptions, open only to men. In particular, jobs requiring more intense physical and/or environmental strain were considered to be beyond the physiological capabilities of women.

Verification of Maximal Oxygen Uptake in Active Military Personnel During Treadmill Running.

Figueiredo, PS, Looney, DP, Pryor, JL, Doughty, EM, McClung, HL, Vangala, SV, Santee, WR, Beidleman, BA, and Potter, AW. Verification of maximal oxygen uptake in active military personnel during treadmill running. J Strength Cond Res 36(4): 1053-1058, 2022-It is unclear whether verification tests are required to confirm "true" maximal oxygen uptake (V̇o2max) in modern warfighter populations.

Effects of modern military backpack loads on walking speed and cardiometabolic responses of US Army Soldiers.

Introduction: Military leaders must understand how modern military equipment loads affect trade-offs between movement speed and physiological strain to optimize pacing strategies.

Purpose: To evaluate the effects of load carried in a recently developed military backpack on the walking speed and cardiometabolic responses of dismounted warfighters.

Methods: Fifteen soldiers (1 woman, 14 men; age, 22 ± 2 years; height, 173 ± 7 cm; body mass (BM), 73 ± 10 kg) completed incremental walking tests with four external load conditions (0, 22, 44, or 66% BM) using the US Army's newest backpack: the Modular Lightweight Load-Carrying Equipment 4000 (MOLLE 4000).

Randomized Trial Comparing Consumption of Military Rations to Usual Intake for 21 Consecutive Days: Nutrient Adequacy and Indicators of Health Status.

Background: The US military Meal, Ready-to-Eat food ration is approved as a nutritionally adequate sole source of nutrition for ≤21 days. However, the ration continuously evolves, requiring periodic reassessment of its influence on nutritional status and health.

Objective: To determine the effects of consuming the US Armed Services Meal, Ready-to-Eat ration for 21 days, relative to usual diets, on nutrient intake, and indicators of nutritional status and cardiometabolic health.

Sensitivity and reliability of zinc transporter and metallothionein gene expression in peripheral blood mononuclear cells as indicators of zinc status: responses to zinc exposure and habitual zinc intake in humans.

Zn is an essential nutrient for humans; however, a sensitive biomarker to assess Zn status has not been identified. The objective of this study was to determine the reliability and sensitivity of Zn transporter and metallothionein (MT) genes in peripheral blood mononuclear cells (PBMCs) to Zn exposure ex vivo and to habitual Zn intake in human subjects. In study 1, human PBMCs were cultured for 24 h with 0-50 µm ZnSO4 with or without 5 µm N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), and mRNA expression of SLC30A1-10, SLC39A1-14, MT1 subtypes (A, B, E, F, G, H, L, M and X), MT2A, MT3 and MT4 mRNA was determined.

Perspective: Guiding Principles for the Implementation of Personalized Nutrition Approaches That Benefit Health and Function.

Personalized nutrition (PN) approaches have been shown to help drive behavior change and positively influence health outcomes. This has led to an increase in the development of commercially available PN programs, which utilize various forms of individual-level information to provide services and products for consumers. The lack of a well-accepted definition of PN or an established set of guiding principles for the implementation of PN creates barriers for establishing credibility and efficacy.

A diet of U.S. military food rations alters gut microbiota composition and does not increase intestinal permeability.

Interactions between gut microbes and dietary components modulate intestinal permeability (IP) and inflammation. Recent studies have reported altered fecal microbiota composition together with increased IP and inflammation in individuals consuming military food rations in austere environments, but could not isolate effects of the diet from environmental factors. To determine how the U.

Acute stressor alters inter-species microbial competition for resistant starch-supplemented medium.

Gut microbiome community dynamics are maintained by complex microbe-microbe and microbe-host interactions, which can be disturbed by stress. studies on the dynamics and manipulation of those interactions are costly and slow, but can be accelerated using fermentation. Herein, fermentation was used to determine how an acute stressor, a sudden change in diet, impacts inter-bacterial species competition for resistant starch-supplemented medium (RSM).

Metabolic Costs of Standing and Walking in Healthy Military-Age Adults: A Meta-regression.

Introduction: The Load Carriage Decision Aid (LCDA) is a U.S. Army planning tool that predicts physiological responses of soldiers during different dismounted troop scenarios.

Dietary Intake and Physical Activity Assessment: Current Tools, Techniques, and Technologies for Use in Adult Populations.

Unlabelled: Accurate assessment of dietary intake and physical activity is a vital component for quality research in public health, nutrition, and exercise science. However, accurate and consistent methodology for the assessment of these components remains a major challenge. Classic methods use self-report to capture dietary intake and physical activity in healthy adult populations.

Ingesting a Combined Carbohydrate and Essential Amino Acid Supplement Compared to a Non-Nutritive Placebo Blunts Mitochondrial Biogenesis-Related Gene Expression after Aerobic Exercise.

Whether load carriage (LC), an endurance exercise mode composed of the aerobic component of traditional endurance exercise [e.g., cycle ergometry (CE)] and contractile forces characteristic of resistive-type exercise, modulates acute mitochondrial adaptive responses to endurance exercise and supplemental nutrition [carbohydrate + essential amino acids (CHO+EAA)] is not known.

AKT2 is the predominant AKT isoform expressed in human skeletal muscle.

Skeletal muscle physiology and metabolism are regulated by complex networks of intracellular signaling pathways. Among many of these pathways, the protein kinase AKT plays a prominent role. While three AKT isoforms have been identified (AKT1, AKT2, and AKT3), surprisingly little is known regarding isoform-specific expression of AKT in human skeletal muscle.

Digital food photography technology improves efficiency and feasibility of dietary intake assessments in large populations eating ad libitum in collective dining facilities.

Background: Accurate assessment of dietary intake continues to challenge researchers, especially in field, or non-laboratory settings.

Objective: In this study, digital food photography (DFP) methodology was used to assess nutritional intake (NI) of Soldiers participating in the US Army's Ranger Selection and Assessment Program (RASP).

Methods: During this high-intensity six-week course, Soldiers complete simulated operational missions, perform various military tasks, and importantly, eating time is severely limited.

Skeletal Muscle myomiR Are Differentially Expressed by Endurance Exercise Mode and Combined Essential Amino Acid and Carbohydrate Supplementation.

Skeletal muscle microRNAs (myomiR) expression is modulated by exercise, however, the influence of endurance exercise mode, combined with essential amino acid and carbohydrate (EAA+CHO) supplementation are not well defined. This study determined the effects of weighted versus non-weighted endurance exercise, with or without EAA+CHO ingestion on myomiR expression and their association with muscle protein synthesis (MPS). Twenty five adults performed 90 min of metabolically-matched (2.

Altered metabolic homeostasis is associated with appetite regulation during and following 48-h of severe energy deprivation in adults.

Background: Military personnel frequently endure intermittent periods of severe energy deficit which can compromise health and performance. Physiologic factors contributing to underconsumption, and the subsequent drive to overeat, are not fully characterized. This study aimed to identify associations between appetite, metabolic homeostasis and endocrine responses during and following severe, short-term energy deprivation.