Technical Reports

A technical report is a technical document that records and disseminates methods and results from research studies and research, development, test, and evaluation (RDT&E) activities. Technical reports are USAARL's principal method of in-depth reporting on technical subjects that are of interest not only to the department, agency, or command sponsoring the work, but also to external groups and laboratories in government, academia, and industry. Technical reports may vary in type, to include technical reports that present the findings of research or analyses or that provide guidance or instruction on matters important to the DoD, journal articles (open access and embargoed text) that have been published under an open access agreement with the publisher or published under a Creative Commons license, conference proceedings that include whole collections of papers presented at a symposium or workshop, and conference papers that could include an individual paper, briefing charts, or a poster presented at a workshop or symposium. For inquiries related to USAARL's technical report(s), contact usarmy-usaarl-library@health.mil.

Featured Reports

For more reports, please visit the technical reports archive page.

Download '2026-37' report PDF

SIZE:4.8 MB

DTIC #:AD1366984

TITLE:Development and Evaluation of Methodologies to Statically Assess Restraint System Designs and Release Loads for Post-Crash Occupant Survivability

AUTHOR(s):Schlick, M., Melara, L., Rhodes, D., Willett, J., Utter, C., McGovern, S., & McEntire, B. J.

ABBREVIATED ABSTRACT:U.S. Army aviators may be exposed to various potentially harmful in-flight or impact events during their missions. In mishap scenarios, the restraint system is designed to secure the occupant to the seat and minimize collisions with the cabin, preventing injuries by maintaining spinal alignment (Willett et al., 2022). Even with the introduction of the U.S. Army Aircraft Crash Survival Guide in 1989, the lower extremities, head, thorax, and spine remain the leading injured body regions in mishaps (Desjardins et al., 1989; Labun, 2014). The first objective of this research aimed to develop a methodology to statically assess occupant restraint systems under 1 G loading, where 1 G represents an acceleration of 32.174 feet per second squared (ft/s2) and evaluate the new method. A conventional five-point restraint system and a Parachute Restraint Harness Assembly-56 Personal (PCU-56\P) torso harness (TH) were used to restrain a test surrogate in a seat inversion wheel fixture for testing. The second aim of this research was the development and execution of a restraint system release assessment methodology. A conventional five-point restraint with a quick release (as described in MIL-S-58095A (AV) was used to evaluate the assessment.Both assessments identified a need to design occupant restraint systems to prevent lateral flail in rotary-wing mishaps. The increased risk of injury during lateral flail, indicated in the static 1 G loading, combined with the risk identified with the five-point release mechanism further emphasized the need for a lateral dynamic seat performance requirement to assess injury risk to the upper extremities, which may prevent egress.

KEYWORDS:Occupant flail, static 1G loading, torso harness, 5-point restraints, seat restraint system, static testing

Download '2026-36' report PDF

SIZE:3.6 MB

DTIC #:AD1366982

TITLE:Preliminary Findings from an Investigation of the Influence of HSM and Inertial Loading Direction On Cervical Spine Injury Risk

AUTHOR(s):Rhodes, D., Brozoski, F. T., Brown, B. A., Johnson, B., Daniel, R., Rooks, T., & Chancey, V. C.

ABBREVIATED ABSTRACT:Current military HSM guidelines for acute injury risk are based primarily on vertical loading in a helicopter crash environment (i.e., loading in the Gz direction) (McEntire & Shanahan, 1998). Research using HSM under longitudinal (-Gx) and lateral (Gy) loadings is becoming increasingly important with future U.S. Army air and ground vehicles incorporating side-facing seats. However, no current guidelines exist for longitudinal (±Gx) inertial loadings, such as those experienced during frontal impacts, or lateral (Gy) loadings for side-facing occupants, such as those experienced during a side impact. The objective of the current study was to investigate the effects of HSM on injury severity under frontal (-Gx) and lateral (Gy) exposures. Observed injuries and kinematics measured at the junction of the seventh cervical and first thoracic vertebra (C7/T1) were documented and compared between HSM groups and loading directions, and initial qualitative impressions are presented. Future research will quantify the influence of HSM and loading direction on cervical spine injury risk.

KEYWORDS:acute injury, lower neck injury, lateral impact, frontal impact, Gx exposure, Gy exposure, neck injury severity

Download '2026-35' report PDF

SIZE:3.7 MB

DTIC #:AD1366974

TITLE:Expert Panel Feedback on Fatigue Impacts on Cognitive and Functional Performance of Flight Paramedics

AUTHOR(s):Kelley, A., Kinsler, R., Lloyd, A., Enzor, M., Molles, J., Duffy, M., & Feltman, K.

ABBREVIATED ABSTRACT:The objective of this expert panel was to identify medical scenarios, tasks, and measurable outcomes for use in an upcoming prolonged en route casualty care study. The discussion yielded key takeaways such as the type of tasks to employ (those requiring critical thinking skills such as medication and dosing calculations, ventilator management, troubleshooting and response to alarms, and documentation), and the implementation of multiple patient scenarios and extended durations to exacerbate fatigue effects.

KEYWORDS:en-route care, flight paramedics, performance

Download '2026-33' report PDF

SIZE:3.9 MB

DTIC #:AD1366971

TITLE:Whole-Body Vibration Effects on En Route Care Provider Performance - Survey of U.S. Army En Route Care Medical Providers and Potential Mitigation and Training Strategies

AUTHOR(s):Madison, A., Long, B., Garnett, H., Vasquez, K., Barazanji, K., Traxler, S., Brown, B., & Chancey, V. C.

ABBREVIATED ABSTRACT:Daily operations for military en route care medical providers during casualty evacuation (CASEVAC) and medical evacuation (MEDEVAC) missions include performing lifesaving medical care interventions in tight spaces and awkward positions during dynamic vehicle motion (e.g., vibration, and jolt). This report leveraged an anonymous, comprehensive survey assessment approach to examine the impacts of dynamic vehicle motion on U.S. Army en route care medical providers during air and ground CASEVAC and MEDEVAC missions. The survey consisted of 76 quantitative and qualitative-based questions, of which 29 questions were analyzed to validate earlier findings on the effects of WBV on performance and potential WBV mitigation strategies. Standardized survey questions included a task analysis (2024 U.S. Army Aeromedical Evacuation SMOG task list) to assess susceptibility to WBV, the potential detriment to the patient if delayed, and the difficulty in performing within a WBV environment. Forty-seven experienced U.S. Army (current or prior) en route care medical providers completed the survey. Airway and respiratory management tasks and shock and circulation tasks are most challenging to perform and most susceptible to WBV and include those with the greatest detriment to the patient if delayed. The most common mitigation strategies used to combat WBV were stabilization techniques, creating pre-made task kits, completing tasks before vehicle/aircraft movement (if possible), and maintaining effective communication with the crew. The survey validated and provided additional mitigation and training strategies to previous USAARL foundational work that explored challenges related to completing en route care tasks in dynamic vehicle motion settings. Survey respondents stated that current training can be improved and optimized to include (1) environmental training exposure (e.g., dynamic vehicle motion); (2) access to live tissue and human or human surrogate (e.g., manikin or cadaver) during training; and (3) stress and composure management techniques. Study outcomes should help inform future medical care practices, trainings, policies, as well as future designs for equipment (i.e., medical, helmets, body armor, etc.) and military vehicles.

KEYWORDS:MEDEVAC, CASEVAC, whole-body vibration, WBV, WBV mitigation strategies

Download '2026-32' report PDF

SIZE:6.9 MB

DTIC #:AD1366969

TITLE:Evaluation of Aeromedical Patient Movement Systems in Vertical Accelerative Exposures for the Development of A Dynamic Test Standard

AUTHOR(s):Rhodes, D., Schlick, M., Johnson, B., Willett, J., Melara, L., Booms, S., & McEntire, B. J.

ABBREVIATED ABSTRACT:Protection and survival of aircraft occupants during mishaps should be primary considerations in the design, development, and testing of aeromedical patient movement systems (APMS). All patients being transported, need to have crashworthy litters that will minimize additional injuries during a mishap. The Aircraft Crash Survival Design Guide (ACSDG) recommends a 48 G pure vertical dynamic test (Desjardins et al., 1989); however, dynamic loading specifications do not exist for military patient litters and APMS are not required to meet recommended crashworthy standards for patient safety. Litter system collapse and failure during crash conditions can expose patients, medical attendants, and nearby occupants to additional hazards and injury mechanisms. The objective of this research was to demonstrate the need for the development of a comprehensive vertical dynamic test standard with dynamic test conditions using the USAARL Vertical Acceleration Tower (VAT). The instrumented Hybrid III 95th percentile male anthropomorphic test device (ATD) with a Pedestrian Pelvis (HIII-95M-Ped) and APMS (floor-mounted and elevated) were exposed to two vertical accelerative test severities targeting 7 G and 23 G to evaluate the structural integrity of the APMS and ATD response. Test results demonstrated that even at the lower test severity, deformation of the APMS components was noted and high speed video and sensor analysis confirmed the ATD chest, pelvis, and knees impacted the surface below the litter during the test, indicating a potential increase in injury severity of a patient in a mishap. Preliminary data resulting from this study demonstrates a need for an APMS dynamic testing requirement. Furthermore, floor-mounted and elevated APMS may need to be evaluated differently due to structural differences. Future work should include dynamic APMS tests in multiple loading scenarios with post-mortem human subjects to assess ATD biofidelity in the supine position.

KEYWORDS:litter, dynamic testing, crashworthy litters, crashworthiness, dynamic test standards, anthropomorphic test device, ATD

Download '2026-31' report PDF

SIZE:3.9 MB

DTIC #:AD1366966

TITLE:Evaluation of Signal Quality and Comfort for Wearable EEG Device in the UH-60 Flight Simulator

AUTHOR(s):Atchley, J. A., Duffy, M., Feltman, K., Basso, J., & Yue, X.

ABBREVIATED ABSTRACT:This research test plan activity assessed the comfort, physical durability, and signal quality of the CGX Patch, a two-channel electroencephalogram (EEG) wearable, to determine its viability for simulated flight and performance research at the U.S. Army Aeromedical Research Laboratory (USAARL). Three active-duty soldiers wore the device across three distinct testing phases including resting baselines, a 60-minute physical training (PT) session designed to challenge device adhesion through motion and perspiration, and two simulated UH-60 flights. While subjective ratings indicated the device was well-tolerated in climate-controlled, low-exertion settings, the hydrogel adhesive frequently compromised or failed under moderate-to-heavy perspiration during the PT phase. Beyond physical adhesion, power spectral density analysis of the raw EEG data revealed significant limitations regarding signal quality. The device's aggressive built-in signal filtering suppressed physiologically meaningful neural activity, failing to capture the expected alpha-band increases during the eyes-closed condition. Because of its susceptibility to adhesive failureand its inability to detect rapid, transient neural changes, the CGX Patch is unsuitable for research requiring high temporal validity which limits its potential use case for USAARL research. With that being said, the compact form factor of the device may still have an applicable use case for long-duration, stationary physiologicalmonitoring, such as sleep studies.

KEYWORDS:wearables, EEG, UH-60

Download '2026-30' report PDF

SIZE:5 MB

DTIC #:AD1366962

TITLE:The Effects of Increased Head-Supported Mass and Center of Mass Offset on the Federal Aviation Administration Hybrid III Anthropomorphic Test Device Neck Responses During Vertical Acceleration

AUTHOR(s):Rhodes, D., Johnson, B., Willett, J., Schlick, M., & McEntire, B. J.

ABBREVIATED ABSTRACT:Aviator helmets are often configured with mounted technologies to give U.S. Army Warfighters a tactical advantage over the enemy. The addition of mass from helmet-mounted equipment alters the center of mass (CM) offset away from the natural balance point of the head and increases the stress experienced by the neck. As mission length and flight capabilities continue to grow and mass and CM offset demands change, researchers need to define head-supported mass (HSM) and CM offset boundaries concerning injury in severe but potentially survivable aircraft mishaps. The aim of this study was to challenge the existing U.S. Army Aeromedical Research Laboratory (USAARL) HSM Acute Neck Injury Risk Curve. For this study, the existing USAARL HSM Acute Neck Injury Risk Curve was challenged by exposing the Federal Aviation Administration (FAA) Hybrid III (HIII) anthropometric test device (ATD) with added HSM to vertical acceleration (Gz) levels that are consistent with the crashworthy seat requirements of MIL-S-58095A (canceled) (Department of Defense [DoD], 1986; DoD, 1996). The FAA-HIII ATD was encumbered with defined HSM configurations and tested on the USAARL Vertical Acceleration Tower. This assessment of the USAARL HSM Acute Neck Injury Risk Curve (McEntire & Shanahan, 1998) does not support changing the accepted injury risk threshold at this time, but further research is indicated.

KEYWORDS:head-supported Mass, HSM, injury risk, cervical spine, center of gravity, helmets

Download '2026-29' report PDF

SIZE:3.9 MB

DTIC #:AD1366958

TITLE:Field Testing an In-Ear Monitor for Real-Time Hearing Protective Device (HPD) Testing in Human Subjects (Reprint)

AUTHOR(s):Podloski, A., Brown, A., Jones, H., Noetzel, J., Stefanson, JR, Argo, T., & Greene, N.

ABBREVIATED ABSTRACT:Military personnel in high-noise environments rely heavily on hearing protective devices (HPDs), yet laboratory-rated effectiveness often overestimates the actual protection achieved during dynamic, real-world operational movements. To address this discrepancy, we field-tested a novel in-ear auditory monitoring system to measure real-time sound pressure levels (SPLs) and HPD attenuation on human subjects performing simulated crew activities around a UH-60 Black Hawk with an active auxiliary power unit (85-112 dBA). Continuous simultaneous internal and external SPL recordings calculated an insertion loss of 10-15 dB for single protection and 30-35 dB for double protection. These real-world attenuation levels were consistently lower and more variable than laboratory predictions. Ultimately, this study demonstrates that in-ear dosimetry is a viable, tolerable tool for characterizing true operational noise exposure, highlighting the critical need to update HPD selection, fit-training protocols, and hearing conservation policies to adequately protect Warfighters in the field.

KEYWORDS:field test, hearing protective devices, HPDs

Download '2026-28' report PDF

SIZE:4.4 MB

DTIC #:AD1366956

TITLE:Improving MASCAL CASEVAC Efficiency: An Evaluation of Human Performance during Assisted and Unassisted Litter Carriage (Reprint)

AUTHOR(s):Oldham, R., Robinette, A., McGovern, S., & Ballard, M.

ABBREVIATED ABSTRACT:Introduction: In a potential conflict with a near-peer enemy, casualty evacuation is expected to be more difficult in mode and scale within large scale combat operations (LSCOs); evacuation teams may be required for litter-based extractions to deliver casualties to aid stations. The number of casualties expected in LSCOs will place high physical demand on the evacuation teams. The objective of this work was to evaluate human performance during litter carriage with and without assistive devices in a simulated mass casualty (MASCAL) scenario. Methods: Eight, two-person litter teams volunteered to carry a weighted litter on a 50-meter course for 20 minutes per condition: with a shoulder harness (SH), with wrist hooks (WH), and unassisted (UA). Total time and timing of events were collected via custom software. The average casualty evacuation (CASEVAC) time by carry condition, representing the total time to evacuate one casualty, was calculated by averaging the time to pick up, carry, rest (if needed), and drop off the litter for all teams. Average speeds for all teams by carry condition were calculated from active litter movement including any needed rests, excluding pickup and drop-off times. One-way repeated measures ANOVAs were conducted to identify the effect of carry condition on CASEVAC time and average speed. Pairwise post-hoc analysis, with the Bonferroni correction, was conducted for any statistically significant (p < 0.05) findings. Results: The average CASEVAC times of all carries were 73.30 seconds (s), 61.61 s, and 100.59 s for SH, WH, and UA, respectively. Pairwise post-hoc analysis revealed statistically significant differences between SH and WH, SH and UA, and WH and UA (p-adjusted 0.041, 0.038, and 0.012, respectively). The average speed was 2.59 miles per hour (mph), 2.90 mph, and 2.12 mph for SH, WH, and UA, respectively. Pairwise post-hoc analysis revealed statistically significant differences between SH and WH, SH and UA, and WH and UA (p-adjusted 0.005, 0.048, and 0.005, respectively). Conclusion: Assisted carry conditions (SH and WH) had lower average CASEVAC times and faster average speeds than unassisted carry (UA). This suggests that assistive devices can improve MASCAL CASEVAC by allowing for less downtime and more casualty movement compared to unassisted carry. Faster evacuations with a two-person litter team are strategically crucial to increasing the survivability of wounded Service Members and those assisting with their evacuation.

KEYWORDS:litter carriage, mass casualty, MASCAL, dismounted litter transport, casualty transport

Download '2026-26' report PDF

SIZE:892 KB

DTIC #:AD1364356

TITLE:Acute Thoracoabdominal Trauma and Incapacitation Injury Tolerance and Criteria Development Stakeholder Meeting Summary

AUTHOR(s):Rhodes, D., & McEntire, B. J.

ABBREVIATED ABSTRACT:A virtual stakeholder meeting was convened on April 23, 2025 to disseminate emerging results of the U.S. Army Medical Research and Development Command (USAMRDC) funded research on acute thoracoabdominal trauma and incapacitation injury tolerance and criteria development. Participants reviewed progress on biomechanical research aimed at developing injury risk curves for thoracoabdominal regions. Key findings highlighted the need for enhanced medical injury criteria to address emerging threats, such as lightweight body armor and high-velocity impacts. Presentations covered experimental methodologies, scaling techniques, and translational research challenges, and emphasized the importance of integrating physiological data. Stakeholders discussed future directions, including the development of new surrogates, injury grading schemes, and operational vignettes to inform military practices. The meeting underscored the importance of collaboration and innovation in advancing protective equipment standards for Warfighter survivability.

KEYWORDS:behind armor blunt trauma (BABT), behind helmet blunt trauma (BHBT), acute thoracoabdominal trauma, human surrogates, medical injury criteria, injury scoring, incapacitation injury tolerance and criteria

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