David P Looney

U.S. Army Research Institute of Environmental Medicine · Military Performance Division

Introduction: The load carriage decision aid (LCDA) walking equation was developed from literature-aggregated group mean data to calculate standing and level walking energy expenditures in healthy, military-age adults. The LCDA walking equation has not been validated for use in individuals or graded walking. Purpose: We aimed to validate the LCD...

Purpose Body surface area (BSA) is an important measurement for many thermophysiological, pharmaceutical, toxicological, environmental, and military applications. Unfortunately, BSA is difficult to quantify, and existing prediction methods are not optimized for contemporary populations. Methods The present study analyzed data body measurements fro...

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. M...

Introduction: Existing predictive equations underestimate the metabolic costs of heavy military load carriage. Metabolic costs are specific to each type of military equipment and backpack loads often impose the most sustained burden on the dismounted warfighter. Purpose: Develop and validate an equation for estimating metabolic rates during heav...

Objectives: To improve predictive formulae for estimating body surface area (BSA) in healthy men and women using a modern three-dimensional scanner technology. Methods: Body surface areas were obtained from a convenience sample of 1267 US Marines (464 women and 803 men) using a whole body surface scanner (Size Stream SS20). The reliability of SS...

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 2) and carbon dioxide...

Introduction: Physiological limits imposed by vest-borne loads must be defined for optimal performance monitoring of the modern dismounted warfighter. Purpose: To evaluate how weighted vests affect locomotion economy and relative cardiometabolic strain during military load carriage while identifying key physiological predictors of exhaustion lim...

Measures of human motion provide a rich source of health and physiological status information. This paper provides examples of motion-based biomarkers in the form of patterns of movement, quantified physical activity, and characteristic gaits that can now be assessed with practical measurement technologies and rapidly evolving physiological models...

Warfighters complete strenuous physical activity on their feet throughout their military careers. While greater physiologic costs of walking have been demonstrated with older models of military combat boots versus running shoes, these quantitative differences may not be applicable for contemporary military footwear. The purpose of this study was to...

Purpose: To assess the V̇O2 uptake obtained during a GXT and subsequent verification phase in untrained participants in a hot environment. Methods: Twelve sedentary males completed a GXT followed by a biphasic supramaximal-load verification phase in a hot environment (39 ° C, 32% relative humidity). Rest between tests occurred in a temperate cha...

Understanding the physiological demands on Soldiers when carrying various weapon systems is critical for safe and successful training, mission planning, and real world operations. This report introduces foundational characteristics of both currently used and Next Generation Squad Weapon (NGSW) systems. Research gaps regarding rifle carriage are ide...

Bioelectrical impedance analysis (BIA) provides a practical method of body composition estimation for field research and weight management programmes, with devices and algorithms that have improved in recent years. We compared suitability of a commercial BIA system that uses multi-frequency-based proprietary algorithms (InBody 770, Cerritos, Califo...

This report outlines the findings from an assessment of the BCMAP, intended to provide data and options for Marine Corps policies and standards. Body composition and fitness data was obtained from 2,175 volunteer Marines at three geographical locations. Women who failed the weight screen usually also failed percent body fat (%BF); while 30% of men...

The National Institute for Occupational Safety and Health recommendations for work in the heat suggest workers consume 237 mL of water every 15-20 min and allow for continuous work at heavy intensities in hot environments up to 34 °C and 30% relative humidity. The goal was to determine whether the National Institute for Occupational Safety and Heal...

Periodized endurance training requires exercise-specific knowledge of the cardiovascular demands of training to optimize long-term performance improvements. Tactical strength and conditioning communities lack resources for forecasting heart rate responses to common endurance exercises performed by dismounted warfighters such as military load carria...

PURPOSE: To examine the effect of varying military rucksack loads on the ratio between perceived exertion and metabolic rate. METHODS: Nineteen healthy volunteers (age, 23.8 ± 7.0 years; body mass, 75.1 ± 13.5 kg; height, 173.4 ± 7.5 cm) walked at three treadmill speeds (0.45, 0.89, and 1.34 m·s-1) while carrying four different external load condit...

Introduction It is unclear whether immersion heat acclimation benefits exercise in warm water conditions. This study examined the effects of heat acclimation strategies on heart rate (HR), core temperature, and time to exhaustion (TTE) during cycling exercise in varying warm water conditions. Methods Twenty male divers completed this study at the...

Mathematical models of human thermal responses can be used to provide useful information to prevent heat injuries, plan risk mitigation strategies, and evaluate potential responses to stressors. This paper reviews the mathematical principles used to operate the SCENARIO thermal model. SCENARIO is a rational first principles model that consists of s...

Media reports on 14 March 2022 suggested that Russian soldiers bogged down in vehicles, possibly without fuel resupply, were at serious risk for hypothermia and/or surrender in the next 72 hours due to predicted ambient temperatures as low as -20°C near Kyiv. This short report demonstrates the power of predictive thermal models developed by USARIEM...

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...

This report provides a brief review of the HSDA and includes a brief summary of validation conditions and results for chemical protective clothing and tables of chemical protective clothing values for use in HSDA. This work specifically supports requirements to evaluate the US Army Research Institute of Environmental Medicine (USARIEM) Heat Strain...

The accuracy of the Heat Strain Decision Aid (HSDA) was assessed for predicting core body temperature (Tc) associated with US Army Ranger Training Brigade (RTB) self-paced road marches during Spring, Summer, and Winter classes. Physiological data was collected from 65 Ranger students (Spring: n = 15, Summer: n = 20, Winter: n = 30) along with an as...

This report is a direct response to a request for information (RFI), “Extreme cold rated disposable medical treatment gloves; (RFI USARAK 21-1, Nitrile/Latex Gloves)” from US Army Alaska (USARAK), via the US Army Combat Capabilities Development Command (DEVCOM) Field Assistance in Science and Technology (FAST) Science Advisor, Mr. Scott Martin. The...

Explosive ordnance disposal (EOD) operators wear fully encapsulating suits to protect them from potential fragments and blast while disarming or destroying threats; however, these suits impose excess heat and cardiovascular strain. This work provides a practical method for planning safe working durations of these extremely hazardous and unique acti...

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 XX(X): 000-000, 2021-It is unclear whether verification tests are required to confirm "true" maximal oxygen uptake (...

Objectives We aimed to determine the agreement between actual and predicted core body temperature, using the Heat Strain Decision Aid (HSDA), in non-Ground Close Combat (GCC) personnel wearing multi terrain pattern clothing during two stages of load carriage in temperate conditions. Design Cross-sectional. Methods Sixty participants (men = 49, wo...

This work investigates the use of 3D scanner-derived body measurements to predict individual differences in walking metabolic rate. Methods: Eighteen Soldiers (16 male and 2 females; age 25.6 ± 6.9 years, height 174.3 ± 7.3 cm, body mass (BM) 74.3 ± 12.8 kg) participated in a controlled load carriage study. Volunteers were each assessed by a 3D ful...

Purpose We compared the accuracy and design of two thermoregulatory models, the US Army's empirically designed Heat Strain Decision Aid (HSDA) and the rationally based Health Risk Prediction (HRP) for predicting human thermal responses during exercise in hot and humid conditions and wearing chemical protective clothing. Methods Accuracy of the HSD...

This report provides a quantitative comparison of two different cooling vests and compares simulated performance in two environmental conditions, three metabolic rates, while wearing a chemical protective ensemble. Standard thermal manikin assessments were conducted for a chemical protective ensemble and specifically for two cooling vests: the Air...

Verification tests to confirm graded exercise test (GXT) V[Combining Dot Above]O2max are growing in popularity but the validity and reliability of such testing in the heat remains unknown. Purpose: To evaluate the validity and reliability of a verification test to confirm GXT V[Combining Dot Above]O2max in a hot environment. Methods: Twelve rec...

There is a lack of quantitative data describing the impact that added load has on an individual's standing metabolic rate. Fourteen male US Army Soldiers (age 21 ± 2 years; height 174 ± 7 cm; body mass 73 ± 10 kg) stood 6 minutes with four loads (0, 22, 44, and 66% body mass) while wearing a respirator mask connected to a metabolic cart. Oxygen upt...

This report provides a quantitative assessment of the biophysical properties and simulated thermal responses for the Tactical Advanced Threat Protective Ensemble (TATPE) Chemical Biological (CB) Protective suit; the TATPE CB suit plus the Improved Outer Tactical Vest (IOTV) body armor with front, back and side plates; and the TATPE CB suit plus the...

Quantifying the relationship between the physical properties of clothing worn at or near comfortable conditions to the wearer’s physiological responses is of significant interest to a broad range of users and developers. This study developed and evaluated methods for quantifying these relationships. The physiological responses of nine healthy Soldi...

This study details a technique for comparing the evaporative capacity of fabrics. A Sweating Guarded Hot Plate (SGHP) was used to measure peak evaporative heat flux. In addition to the method we introduce, two commonly-used moisture transfer tests were performed for comparison, a longitudinal wicking “strip” test, and ASTM F1868-17 SGHP analysis of...

Purpose The accuracy of the US Army's Cold Weather Ensemble Decision Aid (CoWEDA) was assessed for the prediction of human skin temperatures while exposed to cold environmental conditions. Methods Data from four laboratory cold exposure studies were combined to examine skin temperature responses based on environment, clothing, and activities. This...

This paper demonstrates a novel approach in human thermoregulatory modeling. A male torso model was created from medical image data. This allowed for accurate geometry of the organs to be used when modeling thermoregulation. Thermoregulation was simulated through heat transfer using finite element analysis. The thermoregulatory activities consisted...

New uniforms have been developed specifically for hot and humid environments. Methods: Standard tests for the thermal and evaporative resistances (Rt and Ret) were conducted (ASTM F1291-16 & ASTM F2370-16) for two US Army uniforms, the new Improved Hot Weather Combat Uniform (IHWCU) and the currently fielded Fire Resistant Army Combat Uniform (FRAC...

Introduction: Thermal insulation of clothing depends largely on the air trapped between the skin and the clothing layers. Textile from clothing layers and the air between layers provide insulation. The purpose of this work is to examine the effects of layers and air gaps on thermal insulation and vapor permeability. Methods: Standard tests for the...

The purposeful distribution of speed, power, or energy is termed as the pacing or pacing strategy and is recognized as a key determinant in optimal run performance. There is no agreement on the best pacing strategy for all runners and race types. Thus, the challenge posed to runners and practitioners is pacing strategy selection and in-race adheren...

Physiological responses to work in cold water have been well studied but little is known about the effects of exercise in warm water; an overlooked but critical issue for certain military, scientific, recreational, and professional diving operations. This investigation examined core temperature responses to fatiguing, fully-immersed exercise in ext...

Purpose: We examined the accuracy of the Heat Strain Decision Aid (HSDA) as a predictor of core body temperature in healthy individuals wearing chemical protective clothing during laboratory and field exercises in hot and humid conditions. Methods: The laboratory experiment examined three chemical protective clothing ensembles in eight male volu...

The ability to model and simulate the rise and fall of core body temperature is of significant interest to a broad spectrum of organizations. These organizations include the military, as well as both public and private health and medical groups. To effectively use cold models, it is useful to understand the first principles of heat transfer within...

This study examined complex terrain march performance and cardiorespiratory responses when carrying different Soldier loads. Nine active duty military personnel (age, 21 ± 3 yr; height, 1.72 ± 0.07 m; body mass (BM), 83.4 ± 12.9 kg) attended two test visits during which they completed consecutive laps around a 2.5-km mixed terrain course with eithe...

This report outlines biophysical properties of two different military head-worn covers, a prototype Afghanistan military cover and the current issue US Army patrol cover. This work describes the methods for calculating their biophysical inputs based on a whole human ensemble, and shows modeling results of the predicted thermoregulatory response dif...

Sekiguchi, Y, Huggins, RA, Curtis, RM, Benjamin, CL, Adams, WM, Looney, DP, West, CA, and Casa, DJ. Relationship between heart rate variability and acute:chronic load ratio throughout a season in NCAA D1 men's soccer players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was twofold: (a) to examine the relationship between hear...

Introduction: The Load Carriage Decision Aid (LCDA) is a US Army planning tool that predicts physiological responses of Soldiers during different dismounted troop scenarios. We aimed to develop an equation that calculates standing and walking metabolic rates in healthy military-age adults for the LCDA using a meta-regression. Methods: We searche...

Background: Predicting the energy costs of human travel over snow can be of significant value to the military and other agencies planning work efforts when snow is present. The ability to quantify, and predict, those costs can help planners determine if snow will be a factor in the execution of dismounted tasks and operations. To adjust predictive...