Movement Quality Assessment of Army Reserve Officers' Training Corps Cadets: A Report of Validity and Normative Data

INTRODUCTION

Movement quality screening in early-career military populations, like Army Reserve Officers' Training Corps (AROTC) cadets, could decrease the negative impact of musculoskeletal injury observed within the military. Movement quality screening techniques should be valid before being pursued in the field. Normative data describing movement quality of AROTC cadets are also needed. Therefore, the aims of this study were to determine criterion validity of several movement quality assessments and report normative jump-landing kinematics of AROTC cadets.

MATERIALS AND METHODS

This cross-sectional research was approved by the Institutional Review Board. As part of a larger study, 20 AROTC cadets (21.3 ± 3.4 years; 1.7 ± 0.1 m; 73.8 ± 14.8 kg) had 3-dimensional (3D) and 2-dimensional (2D) kinematic data collected simultaneously while performing a jump-landing task. Variables of interest were 3D hip and knee sagittal, frontal, and transverse joint angles at maximum knee flexion. An experienced rater calculated sagittal and frontal 2D joint angles at maximum knee flexion. Averages of 2D and 3D angles were calculated to describe normative data and for further data analysis. Bivariate correlations between 3D and 2D variables were used to determine criterion validity.

RESULTS

Moderate correlations were found between 2D and 3D hip frontal plane angles (P = .05, r =-0.33), 2D and 3D knee sagittal plane angles (P = .04, r = 0.35), and 2D and 3D knee frontal plane angles (P = .03, r = -0.36). Normative values of knee and hip kinematics demonstrated averages of 17.58° of knee adduction, 16.48° of knee external rotation, 11.57° of hip abduction, 10.76° of hip internal rotation, and 103.47° of knee flexion during landings. However, ranges demonstrated that landing patterns vary within AROTC cadets.

CONCLUSIONS

The normative values of 3D jump-landing kinematic data indicate that movement quality varies greatly within AROTC cadets, and some cadets display potentially injurious movements. Therefore, screening movement quality could be beneficial to determine musculoskeletal injury risk in AROTC cadets. Based on the correlations discovered in this study, we recommend the 2D techniques used in this study be researched further as they may serve as alternatives to expensive, timely 3D techniques that could be better utilized in military environments.

Pain after combat injury in male UK military personnel deployed to Afghanistan

BACKGROUND

Chronic pain after injury poses a serious health burden. As a result of advances in medical technology, ever more military personnel survive severe combat injuries, but long-term pain outcomes are unknown. We aimed to assess rates of pain in a representative sample of UK military personnel with and without combat injuries.

METHODS

We used data from the ADVANCE cohort study (ISRCTN57285353). Individuals deployed as UK armed forces to Afghanistan were recruited to include those with physical combat injuries, and a frequency-matched uninjured comparison group. Participants completed self-reported questionnaires, including 'overall' pain intensity and self-assessment of post-traumatic stress disorder, anxiety, and depression.

RESULTS

A total of 579 participants with combat injury, including 161 with amputations, and 565 uninjured participants were included in the analysis (median 8 yr since injury/deployment). Frequency of moderate or severe pain was 18% (n=202), and was higher in the injured group (n=140, 24%) compared with the uninjured group (n=62, 11%, relative risk: 1.1, 95% confidence interval [CI]: 1.0-1.2, P<0.001), and lower in the amputation injury subgroup (n=31, 19%) compared with the non-amputation injury subgroup (n=109, 26%, relative risk: 0.9, 95% CI: 0.9-1.0, P=0.034). Presence of at least moderate pain was associated with higher rates of post-traumatic stress (RR: 3.7, 95% CI: 2.7-5.0), anxiety (RR: 3.2, 95% CI: 2.4-4.3), and depression (RR: 3.4, 95% CI: 2.7-4.5) after accounting for injury.

CONCLUSION

Combat injury, but not amputation, was associated with a higher frequency of moderate to severe pain intensity in this cohort, and pain was associated with adverse mental health outcomes.

Viability of Structured Gait Retraining for Improving Clinical Outcomes Following Running-related Injury in Active Duty Service Members

INTRODUCTION

All branches of the U.S. Military have a running component of their physical readiness testing battery. Running-related musculoskeletal injuries affect 20 to 40% of DoD Service Members each year. Running form has not historically been addressed with military running-related injuries. To assess the utility of a structured gait retaining protocol designed to treat the onset of running-related pain and/or injury by correcting identified biomechanical risk factors for injury and improve clinical outcomes.

STUDY DESIGN

Case series.

MATERIALS AND METHODS

A total of 160 Active Duty Service Members (ADSMs) with running-related lower-body musculoskeletal injuries were referred by a physical therapist for a multisession gait retraining program termed "Run with CLASS" (Cadence, Lean, Alignment, Soft-landing, Strike). Run with CLASS utilized various drills to emphasize impact progression, proximal strengthening, and proprioception and spatial awareness.

RESULTS

Results revealed that the implemented gait retraining protocol significantly improved running parameters following lower-body injury as evidenced by increased cadence, improved functional assessment scores, and a marked transition from predominantly heel strike to forefoot strike patterns during running.

CONCLUSIONS

A 3-week supervised gait retraining program focused on the gait retraining program termed "Run with CLASS" (Cadence, Lean, Alignment, Soft-landing, Strike) was successful in altering biomechanics of self-selected running gait by increasing cadence and transitioning ADSMs to a forefoot foot strike. Additionally, ADSMs reported significant improvements on the self-reported functional scores on the University of Wisconsin Running Injury and Recovery Index and Single Assessment Numerical Evaluation.

LEVEL OF EVIDENCE

4.

Common Data Elements and Databases Essential for the Study of Musculoskeletal Injuries in Military Personnel

INTRODUCTION

Injuries are the leading cause of medical encounters with over 2 million medical encounters for musculoskeletal (MSK) conditions and over 700,000 acute injuries per year. Musculoskeletal injuries (MSKIs) are by far the leading health and readiness problem of the U.S. Military. The Proceedings of the International Collaborative Effort on Injury Statistics published a list of 12 data elements deemed necessary for injury prevention in the civilian population; however, there are no standardized list of common data elements (CDEs) across the DoD specifically designed to study MSKIs in the Military Health System (MHS). This study aims to address this gap in knowledge by defining CDEs across the DoD for MSKIs, establishing a CDE dictionary, and compiling other necessary information to quantify MSKI disease burden in the MHS.

MATERIALS AND METHODS

Between November 2022 and March 2023, we conducted an environmental scan of current MSKI data metrics across the DoD. We used snowball sampling with active engagement of groups housing datasets that contained MSKI data elements to determine CDEs as well as information on readiness databases across the DoD containing up-to-date personnel information on disease, hospitalizations, limited duty days (LDDs), and deployability status for all military personnel, as well as MSKI-specific measures from the MHS Dashboard which tracks key performance measures.

RESULTS

We identified 8 unique databases: 5 containing demographic and diagnostic information (Defense Medical Surveillance System, Medical Assessment and Readiness Systems, Military Health System Data Repository, Person-Data Environment, and Soldier Performance, Health, and Readiness Database); and 3 containing LDD information (Aeromedical Services Information Management System, eProfile, and Limited Duty Sailor Marines Readiness Tracker). Nine CDEs were identified: DoD number, sex, race, ethnicity, branch of service, rank, diagnosis, Common Procedural Terminology coding, and cause codes, as they may be captured in any database that is a derivative of the Military Health System Data Repository. Medical Assessment and Readiness Systems contained most variables of interest, excluding injury/place of region and time in service. The Limited Duty Sailor Marines Readiness Tracker contains a variable corresponding to "days on limited duty." The Aeromedical Services Information Management System uses the "release date" and "profile date" to calculate LDDs. The eProfile system determines LDDs by the difference between the "expiration date" and "approved date." In addition, we identified 2 measures on the MHS Dashboard. One measures the percentage of service members (SMs) who are on limited duty for longer than 90 days because of an MSKI and the other tracks the percentage of SMs that are not medically ready for deployment because of a deployment-limiting medical condition.

CONCLUSIONS

This article identifies core data elements needed to understand and prevent MSKIs and where these data elements can be found. These elements should inform researchers and result in evidence-informed policy decisions supporting SM health to optimize military force readiness.

Can a Psychologic Profile Predict Successful Return to Full Duty After a Musculoskeletal Injury?

BACKGROUND

Psychologic variables have been shown to have a strong relationship with recovery from injury and return to work or sports. The extent to which psychologic variables predict successful return to work in military settings is unknown.

QUESTIONS/PURPOSES

In a population of active duty soldiers, (1) can a psychologic profile determine the risk of injury after return to full duty? (2) Do psychologic profiles differ between soldiers sustaining injuries in the spine (thoracic or lumbar) and those with injuries to the lower extremities?

METHODS

Psychologic variables were assessed in soldiers returning to full, unrestricted duty after a recent musculoskeletal injury. Most of these were noncombat injuries from work-related physical activity. Between February 2016 and September 2017, 480 service members who were cleared to return to duty after musculoskeletal injuries (excluding those with high-velocity collisions, pregnancy, or amputation) were enrolled in a study that tracked subsequent injuries over the following year. Of those, we considered individuals with complete 12-month follow-up data as potentially eligible for analysis. Based on that, approximately 2% (8 of 480) were excluded because they did not complete baseline surveys, approximately 2% (11 of 480) were separated from the military during the follow-up period and had incomplete injury data, 1% (3 of 480) were excluded for not serving in the Army branch of the military, and approximately 2% (8 of 480) were excluded because they were not cleared to return to full duty. This resulted in 450 soldiers analyzed. Individuals were 86% (385 of 450) men; 74% (331 of 450) had lower extremity injuries and 26% (119 of 450) had spinal injuries, including soft tissue aches and pains (for example, strains and sprains), fractures, and disc herniations. Time-loss injury within 1 year was the primary outcome. While creating and validating a new prediction model using only psychological variables, 19 variables were assessed for nonlinearity, further factor selection was performed through elastic net, and models were internally validated through 2000 bootstrap iterations. Performance was deciphered through calibration, discrimination (area under the curve [AUC]), R 2 , and calibration in the large. Calibration assesses predicted versus actual risk by plotting the x and y intersection of these values; the more similar predicted risk values are to actual ones, the closer the slope of the line formed by the intersection points of all subjects is to equaling "1" (optimal calibration). Likewise, perfect discrimination (predicted injured versus actual injured) presents as an AUC of 1. Perfect calibration in the large would equal 0 because it represents the average predicted risk versus the actual outcome rate. Sensitivity analyses stratified groups by prior injury region (thoracic or lumbar spine and lower extremity) as well as the severity of injury by days of limited duty (moderate [7-27 days] and severe [28 + days]).

RESULTS

A model comprising primarily psychologic variables including depression, anxiety, kinesiophobia, fear avoidance beliefs, and mood did not adequately determine the risk of subsequent injury. The derived logistic prediction model had 18 variables: R 2 = 0.03, calibration = 0.63 (95% confidence interval [CI] 0.30 to 0.97), AUC = 0.62 (95% CI 0.52 to 0.72), and calibration in the large = -0.17. Baseline psychologic profiles between body regions differed only for depression severity (mean difference 1 [95% CI 0 to 1]; p = 0.04), with greater mean scores for spine injuries than for lower extremity injuries. Performance was poor for those with prior spine injuries compared with those with lower extremity injuries (AUC 0.50 [95% CI 0.42 to 0.58] and 0.63 [95% CI 0.57 to 0.69], respectively) and moderate versus severe injury during the 1-year follow-up (AUC 0.61 [95% CI 0.51 to 0.71] versus 0.64 [95% CI 0.64 to 0.74], respectively).

CONCLUSION

The psychologically based model poorly predicted subsequent injury. This study does not minimize the value of assessing the psychologic profiles of injured athletes, but rather suggests that models looking to identify injury risk should consider a multifactorial approach that also includes other nonpsychologic factors such as injury history. Future studies should refine the most important psychologic constructs that can add the most value and precision to multifactorial models aimed at identifying the risk of injury.

LEVEL OF EVIDENCE

Level III, prognostic study.

Prevalence of Pain With Movement in Active Duty US Army Soldiers

INTRODUCTION

Soldiers must be able to perform a multitude of physically demanding tasks as part of their regular duty, but their physical readiness is often degraded due to pain and musculoskeletal injury (MSKI). The presence of pain with movement has been associated with increased MSKI risk in Soldiers. Improved awareness of the prevalence of painful movements in uninjured Soldiers could help inform Army injury mitigation efforts. The purpose of this study was to identify the prevalence of pain with movement in a population of healthy active duty Soldiers.

MATERIALS AND METHODS

The Selective Functional Movement Assessment-Top Tier Movements (SFMA-TTM), active range of motion (AROM) of the hips and shoulders, and the elicitation of pain with movement were measured in 268 healthy US Army Soldiers. Descriptive statistics were generated for the number of painful movements for each measure and inferential statistics; independent t-test and one-way independent analysis of variance (ANOVA) were used for analysis of the other measures.

RESULTS

Greater than half (59%) of the participants reported pain with at least 1 movement and more than 41% reported pain with 2 or more movements. Soldiers reported a mean of 1.35 painful movements on the SFMA-TTM assessment and a mean of 1.54 painful AROM movements.

CONCLUSIONS

Pain with functional movement patterns was common across a sample of uninjured Soldiers. The presence of pain with movement warrants further evaluation as it may impact a Soldier's physical performance, risk for future injury, and overall quality of life.

Medical correlates of first-term attrition in US Navy personnel

INTRODUCTION

First-term attrition (FTA), or failure of a military service member to complete their initial service contract, is a major financial burden and source of lost manpower in the US Navy. The objective of the present study was to examine medical correlates of FTA using healthcare and disability rating data.

METHODS

In this retrospective cohort study, all US Navy-enlisted personnel between the years 2003 and 2018 with FTA (n=58 777) and regular discharge (n=203 084) were identified for analysis from accession dates in the Career History Archival Medical and Personnel System. Medical diagnoses from outpatient and inpatient records were abstracted from the Military Health System Data Repository. For a subgroup of the study population discharged with a disability rating (n=12 880), diagnoses were identified from the Integrated Disability Evaluation System. The FTA and regular discharge groups were compared using relative risks (RRs) and 95% CIs, and per cent differences for the disability subgroup analysis.

RESULTS

Compared with regular discharges, those with FTA were more likely to have outpatient and inpatient diagnoses for mental health disorders. Personality disorder yielded the strongest association with FTA in both outpatient (RR=10.45, 95% CI 9.79 to 11.16) and inpatient settings (RR=18.97, 95% CI 14.16 to 25.42). Other disorders associated with FTA included schizophrenia, substance-related disorders, poisoning by psychotropic agents and adjustment disorders. In the disability analysis, the FTA group relative to regular discharges had the largest per cent differences for 'arthritis, degenerative (hypertrophic or osteoarthritis)' (10.8% vs 2.5%) and 'tibia and fibula, impairment' (3.0% vs 0.4%).

CONCLUSIONS

This study provides evidence that FTA is associated with both mental and physical health conditions. Mental and physical factors related to FTA require further examination, particularly whether pre-enlistment screening or early career intervention could lead to mitigation strategies. Future research should extend this analysis to other services and population subgroups.

Introducing a new method to record injuries during military training: a prospective study among 296 young Norwegian conscripts

INTRODUCTION

Most epidemiological studies in the field of military medicine have been based on data from medical records and registries. The aims of this study were to test a self-reporting injury surveillance system commonly used in sports medicine in a military setting, and to describe the injury pattern among Norwegian army conscripts during a period of military training.

METHOD

A total of 296 conscripts in His Majesty the King's Guard were asked to report all injuries each week for 12 weeks, using a modification of the Oslo Sports Trauma Research Center Questionnaire on Health Problems (OSTRC-H2). We recorded all injuries irrespective of their need for medical attention or consequences for military participation. In addition, we retrieved data on injuries recorded by military physicians in the medical record from the Norwegian Armed Forces Health Register.

RESULTS

The mean weekly response rate was 74%. A total of 357 injuries were recorded, of which 82% were only captured through the OSTRC-H2 and 3% only in the medical records. The average weekly prevalence of injury was 28% (95% CI: 25% to 31%), and 10% (95% CI: 8% to 12%) experienced injuries with a substantial negative impact on training and performance. The greatest injury burden was caused by lower limb injuries, with knee and foot injuries as the predominant injury locations.

CONCLUSION

The OSTRC-H2 is suitable for use in a military setting and records substantially more injuries than the standard medical record. The prevalence of injuries among conscripts is high and comparable with many elite sports.

Immunoengineering Biomaterials for Musculoskeletal Tissue Repair across Lifespan

Musculoskeletal diseases and injuries are among the leading causes of pain and morbidity worldwide. Broad efforts have focused on developing pro-regenerative biomaterials to treat musculoskeletal conditions; however, these approaches have yet to make a significant clinical impact. Recent studies have demonstrated that the immune system is central in orchestrating tissue repair and that targeting pro-regenerative immune responses can improve biomaterial therapeutic outcomes. However, aging is a critical factor negatively affecting musculoskeletal tissue repair and immune function. Hence, understanding how age affects the response to biomaterials is essential for improving musculoskeletal biomaterial therapies. This review focuses on the intersection of the immune system and aging in response to biomaterials for musculoskeletal tissue repair. The article introduces the general impacts of aging on tissue physiology, the immune system, and the response to biomaterials. Then, it explains how the adaptive immune system guides the response to injury and biomaterial implants in cartilage, muscle, and bone and discusses how aging impacts these processes in each tissue type. The review concludes by highlighting future directions for the development and translation of personalized immunomodulatory biomaterials for musculoskeletal tissue repair.

Systematic Review of Injuries and Chronic Musculoskeletal Pain Among High-speed Boat Operators

INTRODUCTION

High-speed boat operators constitute a population at risk of work-related injuries and disabilities. This review aimed to summarize the available knowledge on workplace-related injuries and chronic musculoskeletal pain among high-speed boat operators.

MATERIALS AND METHODS

In this systematic review, we searched Medline, Embase, Scopus, and the Cochrane Library Database for studies, published from 1980 to 2022, on occupational health and hazards onboard high-speed boats. Studies and reports were eligible for inclusion if they evaluated, compared, used, or described harms associated with impact exposure onboard high-speed boats. Studies focusing on recreational injuries and operators of non-planing boats were excluded. The primary outcome of interest was the incidence of acute injuries. The secondary outcome measures comprised the presence of chronic musculoskeletal disorders, pain medication use, and days off work.

RESULTS

Of the 163 search results, 5 (2 prospective longitudinal and 3 cross-sectional cohort studies) were included in this systematic review. A total of 804 cases with 3,312 injuries sustained during 3,467 person-years onboard high-speed boats were included in the synthesis of the results. The pooled incidence rate was 1.0 per person-year. The most common injuries were related to the lower back (26%), followed by neck (16%) and head (12%) injuries. The pooled prevalence of chronic pain was 74% (95% CI: 73-75%) and 60% (95% CI: 59-62%) of the cohort consumed analgesics.

CONCLUSIONS

Despite very limited data, this review found evidence that high-speed boat operators have a higher rate of injuries and a higher prevalence of chronic pain than other naval service operators and the general workforce. Given the low certainty of these findings, further prospective research is required to verify the injury incidence and chronic pain prevalence among high-speed boat operators.

Overview of Navy Medicine's Limited Duty Patient Population

INTRODUCTION

U.S. Navy Medicine's temporary limited duty (LIMDU) program is the primary vehicle for managing the medical care and subsequent career outcomes of the ill and injured active component (AC) Sailors and Marines to ensure a medically ready force. Before the LIMDU Sailor and Marine Readiness Tracker System (SMART) came online, it was very difficult to examine LIMDU program administration metrics, patients' experiences during LIMDU, and their subsequent health and career outcomes. This study examined the LIMDU patient population's demographic, military career, and LIMDU-specific characteristics; identified characteristics that differed significantly by military service; and evaluated potentially modifiable factors associated with patient outcomes.

MATERIALS AND METHODS

A comprehensive SMART extract was used to identify all AC Sailors and Marines in active LIMDU status between October 1, 2016, and September 30, 2019. The SMART extract was merged with comprehensive administrative military personnel data by patient identifiers to create a longitudinal dataset and to conduct descriptive statistics, bivariate, and multivariate logistic regression analyses for this study. The sample included 26,591 AC Sailors and Marines with complete SMART and military personnel records who ended LIMDU on or before September 30, 2019.

RESULTS

During the study's 3-year period, Navy Medicine's rate of initial LIMDU entry by AC personnel increased each year from 2,041 in FY2017 to 2,424 in FY2019 per 100,000 personnel. At the time of initial entry, most LIMDU patients were male (76%), E4-E6 paygrades (54%), and had a single diagnosis recorded in their SMART records (66%). Pain patients (23%) constituted the largest diagnostic group, followed closely by musculoskeletal patients (23%), and then mental and behavioral health patients (20%). Variables that might reflect administration practices of the program did not differ significantly by service, suggesting good internal standardization of LIMDU administration across Navy Medicine. However, bivariate and multivariate analyses identified significant differences by service for almost all personal demographic, LIMDU-specific, and post-LIMDU military career sample characteristics measured at the last LIMDU close date or later. Study results suggested that the Navy and Marine Corps referred Sailors and Marines to start LIMDU for different medical reasons; to receive care from different military treatment facilities; to close LIMDU with different final actions; and to experience different post-LIMDU career outcomes.

CONCLUSION

Navy Medicine's SMART data is an important new resource for LIMDU program evaluation and population-level patient research, despite the data limitations and concerns identified and addressed by this study. The study results provide a baseline empirical understanding about the LIMDU patient population. Further research is necessary to interrogate the validity of these results over a longer period and to initiate other lines of inquiry. While the construction of the larger project's LIMDU patient population longitudinal dataset required a significant initial investment, future dividends from ongoing work are anticipated. Results derived from verified SMART data will benefit Navy Medicine, operational commands, and LIMDU patients alike by informing continuing efforts to improve patient health and career outcomes, identify and implement best clinical and administrative practices, and optimize force readiness.

High Physical Exposure During Female Recruits' Basic Military Training in Sweden-A Descriptive Study

INTRODUCTION

There is a knowledge gap concerning the occurrence of physical complaints/injuries, i.e., musculoskeletal disorders (MSD), among Swedish women who undergo basic military training (BMT). The aims were to describe prevalence and factors related to MSD and explore physical exposure and performance in Swedish female recruits during BMT.

MATERIALS AND METHODS

A total of 144 females (mean age 22 years) who underwent BMT in 2016 participated in this cross-sectional study. Data regarding self-reported MSD, physical performance, physical activity and exercise, motivation and mental and physical preparation, and physical exposure during BMT and perceived health were collected at the end of BMT through the Musculoskeletal Screening Protocol questionnaire. Additional data on muscle strength were retrieved from IsoKai isokinetic lift tests. Descriptive and analytic (paired samples t-test and logistic binary regression) statistics were used.

RESULTS

The prevalence of MSD was high, with 33% (n = 48) reporting MSD before BMT, 78% (n = 113) during, and 50% (n = 72) at the end of BMT. Knee and upper back were the most frequently reported MSD locations. Forty-four (30%) participants felt insufficiently physically prepared for BMT. The physical exposure was high with loaded marches/runs and carrying heavy loads as the most demanding tasks. The longest walking distance was reportedly 55 km, and the reported maximum load was 50 kg. Forty-five participants (31%) had carried a load representing over 50% of their body weight. Most participants reported good to excellent health at the end of BMT. There was a small (8 N) but significant (P = 0.045) increase in mean force over time. Two variables, MSD before BMT (odds ratio 2.24, P = 0.03) and being physically unprepared (odds ratio 3.03, P < 0.01), were associated with MSD at the end of BMT.

CONCLUSION

This study showed that the prevalence of MSD in Swedish female recruits was high before, during, and at the end of BMT, with knee and upper back as the most frequent locations. Although the physical exposure during BMT was occasionally high, self-rated health was mainly perceived as good to excellent at the end of BMT. Previous MSD and being physically unprepared were related to MSD at the end of BMT. These important and relevant findings indicate the necessity for implementing interventions to increase physical fitness and treat MSD at the beginning of BMT.

A Comprehensive Analysis of Injuries During Army Basic Military Training

INTRODUCTION

The injury definitions and surveillance methods commonly used in Army basic military training (BMT) research may underestimate the extent of injury. This study therefore aims to obtain a comprehensive understanding of injuries sustained during BMT by employing recording methods to capture all physical complaints.

MATERIALS AND METHODS

Six hundred and forty-six recruits were assessed over the 12-week Australian Army BMT course. Throughout BMT injury, data were recorded via (1) physiotherapy reports following recruit consultation, (2) a member of the research team (third party) present at physical training sessions, and (3) recruit daily self-reports.

RESULTS

Two hundred and thirty-five recruits had ≥1 incident injury recorded by physiotherapists, 365 recruits had ≥1 incident injury recorded by the third party, and 542 recruits reported ≥1 injury-related problems via the self-reported health questionnaire. Six hundred twenty-one, six hundred eighty-seven, and two thousand nine hundred sixty-four incident injuries were recorded from a total of 997 physiotherapy reports, 1,937 third-party reports, and 13,181 self-reported injury-related problems, respectively. The lower extremity was the most commonly injured general body region as indicated by all three recording methods. Overuse accounted for 79% and 76% of documented incident injuries from physiotherapists and the third party, respectively.

CONCLUSIONS

This study highlights that injury recording methods impact injury reporting during BMT. The present findings suggest that traditional injury surveillance methods, which rely on medical encounters, underestimate the injury profile during BMT. Considering accurate injury surveillance is fundamental in the sequence of injury prevention, implementing additional injury recording methods during BMT may thus improve injury surveillance and better inform training modifications and injury prevention programs.

General and Pain-Associated Psychological Distress Phenotypes Among Patients With Low Back Pain in the Military Health System

OBJECTIVE

The primary objective was to describe rates of general and pain-related psychological distress for individuals with low back pain (LBP) in the Military Health System (MHS). We identified common phenotypes defined by rates of general and pain-related psychological distress and compared phenotypes on their level of pain interference, physical function, anxiety, and depression.

METHODS

We created a cohort from two completed trials assessing nonpharmacological treatment for LBP in the MHS (n = 510 total). The Optimal Screening for Prediction of Referral and Outcome Yellow Flag assessment tool identified the presence of 11 different yellow flags. Latent class analysis (LCA) used yellow flag indicators to identify common psychological phenotypes. We then compared Patient-Reported Outcomes Measurement Information Systems measures of pain interference, physical function, sleep disturbance, depression, and anxiety across phenotypes.

RESULTS

LCA identified five phenotypes (percentage of the sample): low distress (32%), high distress (27%), poor pain coping and low self-efficacy (18%), low self-efficacy and acceptance (14%), and poor pain coping (10%). Highly distressed phenotypes reported higher levels of pain interference, sleep disturbance, depression, and anxiety than those with other phenotypes, whereas the low distress phenotype had significantly lower pain interference and higher physical function scores than those characterized by all other phenotypes.

CONCLUSION

These phenotypes provide opportunities for clinicians and researchers to develop novel LBP treatment pathways tailored to patients with different profiles of psychological distress. Future work is needed to validate their predictive capabilities for clinical outcomes.

Quantitative Analysis of Condition-based Limited Duty Duration of Musculoskeletal Conditions

INTRODUCTION

Musculoskeletal injuries affect nearly a million service members annually within the DoD, ultimately costing the U.S. Military half a billion dollars in direct patient costs and a significant loss to fleet readiness as many members are assigned days on limited duty (LIMDU) until they are deemed medically fit to return to duty (RTD). The new approach implemented by Navy Medicine in 2022, called "condition-based LIMDU," aims to drastically impact the time in which Sailors and Marines spend under a provider's care by assigning LIMDU days based on a standardized set of guidelines. This study provides a quantitative analysis on LIMDU duration, before and after implementation of the new condition-based LIMDU paradigm, to increase the understanding on the effectiveness and impact to fleet readiness and to assess the accuracy of suggested patient outcome timelines.

MATERIALS AND METHODS

De-identified and aggregated data were obtained from the Naval Medical Forces Atlantic's (NMFL) LIMDU Sailor and Marine Readiness Tracker System (SMART) program for all active duty military patients with ICD-10 code for musculoskeletal conditions. Only closed LIMDU cases in which active duty patients were given a final status of RTD were included. This study analyzed top musculoskeletal ICD-10 codes, optimum period (weeks), maximum period (weeks), and average days on LIMDU assigned at NMFL centers (medical and non-medical) for fiscal years 2021 (FY21) and 2022 (FY22). As well as descriptive statistics, t-test analysis was used to test if there was a difference between FY21 and FY22 and at what point the difference was no longer significant. Critical value method was then used to compare the top five most common musculoskeletal injuries to determine the accuracy of recommended LIMDU days to actual average assigned LIMDU per injury type. A color-coded compliance chart was created based on the results.

RESULTS

The results showed that for RTD population, the implementation of condition-based LIMDU significantly decreased average days assigned on LIMDU by 33%. In fact, there is a 35-day (5-week) difference before we can confidently say that the difference between FY21 and FY22 is no longer statistically significant. This significant decrease in LIMDU days, before and after implementation, is a trend consistent at both medical and non-medical NMFL centers; however, medical centers reported significantly more assigned LIMDU days for both years. The five most common injuries of FY21 and FY22 were low back pain, pain in shoulder, pain in hip, pain in knee, and pain in ankle. Before implementation, all five of these injury types far exceeded the recommended amount of LIMDU days. With the new condition-based LIMDU paradigm, the average assigned LIMDU days for pain in hip, pain in knee, and pain in ankle were all found to be in compliance with the recommended LIMDU days within a 99% confidence level.

CONCLUSIONS

The new condition-based LIMDU paradigm is successful in its aim to improve fleet readiness by returning Sailors and Marines to full duty status significantly faster. Regular assessment of ICD-10 diagnosis codes and update to recommended LIMDU assignment timelines should be conducted to maximize the effectiveness and accuracy for all medical conditions.

Treatment of Tendon Injuries in the Servicemember Population across the Spectrum of Pathology: From Exosomes to Bioinductive Scaffolds

Tendon injuries in military servicemembers are one of the most commonly treated nonbattle musculoskeletal injuries (NBMSKIs). Commonly the result of demanding physical training, repetitive loading, and frequent exposures to austere conditions, tendon injuries represent a conspicuous threat to operational readiness. Tendon healing involves a complex sequence between stages of inflammation, proliferation, and remodeling cycles, but the regenerated tissue can be biomechanically inferior to the native tendon. Chemical and mechanical signaling pathways aid tendon healing by employing growth factors, cytokines, and inflammatory responses. Exosome-based therapy, particularly using adipose-derived stem cells (ASCs), offers a prominent cell-free treatment, promoting tendon repair and altering mRNA expression. However, each of these approaches is not without limitations. Future advances in tendon tissue engineering involving magnetic stimulation and gene therapy offer non-invasive, targeted approaches for improved tissue engineering. Ongoing research aims to translate these therapies into effective clinical solutions capable of maximizing operational readiness and warfighter lethality.

Associations Between Rank, Sex, and Parity With Musculoskeletal Injuries Sustained During Annual Military Physical Fitness Test

ABSTRACT

Edwards, CM, da Silva, DF, Puranda, JL, Souza, SCS, Semeniuk, K, and Adamo, KB. Associations between rank, sex, and parity with musculoskeletal injuries sustained during annual military physical fitness test. J Strength Cond Res 38(2): 367-373, 2024-Musculoskeletal injuries pose a significant threat to the well-being of military personnel. Attempts to use physical employment standard test results as predictors of injury are underway, but little is known about injuries sustained during the tests. This study sought to identify body regions most likely to be reported as injured during the annual Canadian Armed Forces (CAF) physical fitness evaluation. In addition, sex, rank, and parity status are explored as possible associated factors for injury. A total of 1,796 actively serving CAF members were categorized by sex (1,030 male participants; 766 female participants), rank (1,142 Non-Commissioned Members [NCM]; 638 Officers), and parity (314 parous female participants; 435 nulliparous female participants). Sex, rank, and parity were associated with body regions reportedly injured during an annual CAF fitness assessment (significance p ≤ 0.05). When compared with male participants, female participants were more likely to be injured {aOR: 1.797 (95% [confidence interval] CI: 1.45-2.23)} and more prone to injury of the wrist (adjusted odds ratio [aOR]: 1.933 [95% CI: 1.20-3.12]), hip (aOR: 3.445 [95% CI: 2.07-5.728]), or lower back (aOR: 1.55 [95% CI: 1.18-2.04]). Non-Commissioned Members were more likely to injure the neck (aOR: 2.14 [95% CI: 1.18-3.88]) or shoulder (aOR: 2.03 [95% CI: 1.31-3.15]), when compared with Officers. Parous female participants reported pelvis/abdomen injury at a higher rate than the nulliparous group (5 vs. 1.7%, p = 0.019). Injuries sustained during an annual CAF fitness assessment differ based on sex, rank, and parity. Canadian Armed Forces female participants, NCM, and parous female participants may require specific physical fitness support in preparation for the annual physical fitness test.

Diagnostic and Therapeutic Challenges in a Military Recruit Training Center of the Hellenic Navy: A Retrospective Analysis of the Poros Registry Serving as a Quality Improvement Project for Medical Officers

INTRODUCTION

Basic military training (BMT) has been associated with increased morbidity burden. Nevertheless, the exact epidemiology of the encountered cases in the BMT of Greek recruits has never been assessed. The aim of this quality improvement project was to investigate for the first time the clinical patterns, rates, and severity of symptoms leading recruits to visit the infirmary of a recruit training center and use this knowledge to provide a practical guidance for the physicians in charge.

MATERIALS AND METHODS

All medical cases which were consecutively examined for the time range from November 2021 to September 2022 at the infirmary of the Hellenic Naval recruit training center in Poros, Greece, were retrospectively analyzed. Logistic regression analyses were performed to identify independent predictors of "severe clinical status" (i.e., overnight sick bay confinement and/or transfer to a tertiary hospital within 24 h) and absence from BMT for at least 1 day.

RESULTS

A total of 2,623 medical cases were examined during four recruit seasons from November 2021 to September 2022. Upper respiratory tract infections (URTIs) and musculoskeletal injuries were the most frequent reasons for a recruit's visit to the infirmary (33.9% and 30.2%, respectively). 6.7% of the total cases were identified as having "severe clinical status." Specifically, in psychiatric, urological, and cardiovascular cases, febrile events were all independently associated with increased risk of "severe clinical status." There was a positive association between training week and absence from BMT, while febrile events and spring recruit season were also independently linked with increased probability of absence from BMT for at least 1 day.

CONCLUSIONS

URTIs and musculoskeletal complaints were the primary reasons for recruits' presentation at the infirmary of a Greek recruit training center, leading to severe rates of attrition. Further registries and quality improvement projects are warranted to reach specific conclusions and reduce BMT-related morbidity and its subsequent implications.

Efficacy of Conservative Interventions for Musculoskeletal Conditions on Pain and Disability in Active Serving Military Personnel-A Systematic Review

INTRODUCTION

Musculoskeletal (MSK) injuries and associated pain disorders are one of the leading causes for soldiers not being medically fit for deployment, impacting force capability and readiness. Musculoskeletal pain continues to be a leading cause of disability within military services and is associated with a substantial financial burden. A better understanding of the effectiveness of MSK pain management strategies is required. This review was designed to determine the efficacy of nonsurgical interventions, such as physiotherapy, exercise, pharmacology, and multidisciplinary programs, to manage MSK conditions in active serving military populations.

MATERIALS AND METHODS

MEDLINE, Embase, CINAHL, and SPORTDiscus were searched to identify relevant randomized clinical trials. Recommended methods were used for article identification, selection, and data extraction. The Cochrane Risk of Bias tool and the Grade of Recommendation, Assessment, Development, and Evaluation were used to appraise the studies. Where possible, meta-analyses were performed. The review was conducted according to the PRISMA guidelines.

RESULTS

Nineteen articles (1,408 participants) met the eligibility criteria. Low back pain (LBP) was the most frequently investigated condition, followed by knee pain, neck pain, and shoulder pain. Early physiotherapy, exercise and adjunct chiropractic manipulation (for LBP), and multidisciplinary pain programs (physiotherapy, occupational therapy, and psychology) (for chronic MSK pain) improved pain (standardized mean difference ranged from -0.39 to -1.34; low strength of evidence). Participation in multidisciplinary pain programs, adjunct chiropractic manipulation, and early physiotherapy improved disability (for LBP) (standardized mean difference ranged from -0.45 to -0.86; low to very low strength of evidence). No studies evaluated pain medication. Dietary supplements (glucosamine, chondroitin sulfate, and manganese ascorbate), electrotherapy, isolated lumbar muscle exercises, home cervical traction, or training in virtual reality showed no benefit. The studies had a high risk of bias, were typically underpowered, and demonstrated high clinical heterogeneity.

CONCLUSIONS

Currently available randomized clinical trials do not provide sufficient evidence to guide military organizations or health care professionals in making appropriate treatment decisions to manage MSK pain in active serving military personnel. Future research is essential to enable evidence-based recommendations for the effective management of MSK pain conditions in this unique population.

The Functional Movement Screen and Self-reported Injury in Senior Military College Cadets

INTRODUCTION

Secular trend of increasing musculoskeletal injuries (MSKIs) across all branches of the U.S. Military is a critical limiting factor in the effective and efficient process of preparing military personnel for combat. The need to evaluate functional capacity beyond current physical fitness test (PFT) standards is the key in understanding an individual's risk of noncombat-related injury. The purpose of this study is to evaluate the relationship between Functional Movement ScreenTM (FMS) scores, incidence of musculoskeletal injuries, and standardized PFT scores among freshman Cadets during their first 10 weeks of enrollment at a senior military college.

MATERIALS AND METHODS

Eighty-two participants (72 male and 10 female participants; mage: 18.2 years) completed the FMS, an institution-specific PFT (2-min maximum pushups, 2-min maximum abdominal crunches, and 1.5 mile timed run), and an Incidence of Injury and Incidence of Pain Questionnaire. Independent t-tests, Spearman's rank correlation coefficients logistic regression analysis, and Receiver Operator Curves were performed to evaluate relationships between the study variables.

RESULTS

FMS composite and PFT sex-normed total scores were higher in females (16.4, 236.1) than in males (15.0, 204.9). Ninety percent of all females reported injury or pain during the 10-week survey period compared to 48% of males.

CONCLUSIONS

No significant difference between FMS scores and injury and pain was found within both sex groups. Therefore, use of the composite FMS score as an indicator for risk of injury or to predetermine PFT performance is not recommended for this study's population. The rate of incidence of injury or pain in Cadets during a 10-week enrolment period is high. Females outperformed males in the FMS and PFT and reported higher rates of injury and pain. The utility of the FMS may be limited when substantially scaled for implementation across entire military populations. Future research should evaluate performance associations of the FMS with Army Combat Fitness Test components in a population of equally distributed sex and race.

Myotonometry is Capable of Reliably Obtaining Trunk and Thigh Muscle Stiffness Measures in Military Cadets During Standing and Squatting Postures

INTRODUCTION

Low back and lower extremity injuries are responsible for the highest percentage of musculoskeletal injuries in U.S. Army soldiers. Execution of common soldier tasks as well as army combat fitness test events such as the three-repetition maximum deadlift depends on healthy functioning trunk and lower extremity musculature to minimize the risk of injury. To assist with appropriate return to duty decisions following an injury, reliable and valid tests and measures must be applied by military health care providers. Myotonometry is a noninvasive method to assess muscle stiffness, which has demonstrated significant associations with physical performance and musculoskeletal injury. The aim of this study is to determine the test-retest reliability of myotonometry in lumbar spine and thigh musculature across postures (standing and squatting) that are relevant to common soldier tasks and the maximum deadlift.

MATERIALS AND METHODS

Repeat muscle stiffness measures were collected in 30 Baylor University Army Cadets with 1 week between each measurement. Measures were collected in the vastus lateralis (VL), biceps femoris (BF), lumbar multifidus (LM), and longissimus thoracis (LT) muscles with participants in standing and squatting positions. Intraclass correlation coefficients (ICCs3,2) were estimated, and their 95% CIs were calculated based on a mean rating, mixed-effects model.

RESULTS

The test-retest reliability (ICC3,2) of the stiffness measures was good to excellent in all muscles across the standing position (ICCs: VL = 0.94 [0.87-0.97], BF = 0.97 [0.93-0.98], LM = 0.96 [0.91-0.98], LT = 0.81 [0.59-0.91]) and was excellent in all muscles across the squatting position (ICCs: VL = 0.95 [0.89-0.98], BF = 0.94 [0.87-0.97], LM = 0.96 [0.92-0.98], LT = 0.93 [0.86-0.97]).

CONCLUSION

Myotonometry can reliably acquire stiffness measures in trunk and lower extremity muscles of healthy individuals in standing and squatting postures. These results may expand the research and clinical applications of myotonometry to identify muscular deficits and track intervention effectiveness. Myotonometry should be used in future studies to investigate muscle stiffness in these body positions in populations with musculoskeletal injuries and in research investigating the performance and rehabilitative intervention effectiveness.

Clustering Research Proposal Submissions to Understand the Unmet Needs of Military Clinicians

INTRODUCTION

The Advanced Medical Technology Initiative (AMTI) program solicits research proposals for technology demonstrations and performance improvement projects in the domain of military medicine. Advanced Medical Technology Initiative is managed by the U.S. Army Telemedicine and Advanced Technology Research Center (TATRC). Advanced Medical Technology Initiative proposals span a wide range of topics, for example, treatment of musculoskeletal injury, application of virtual health technology, and demonstration of medical robots. The variety and distribution of central topics in these proposals (problems to be solved and technological solutions proposed) are not well characterized. Characterizing this content over time could highlight over- and under-served problem domains, inspire new technological applications, and inform future research solicitation efforts.

METHODS AND MATERIALS

This research sought to analyze and categorize historic AMTI proposals from 2010 to 2022 (n = 825). The analysis focused specifically on the "Problem to Be Solved" and "Technology to Demonstrated" sections of the proposals, whose categorizations are referred to as "Problem-Sets" and Solution-Sets" (PS and SS), respectively. A semi-supervised document clustering process was applied independently to the two sections. The process consisted of three stages: (1) Manual Document Annotation-a sample of proposals were manually labeled along each thematic axis; (2) Clustering-semi-supervised clustering, informed by the manually annotated sample, was applied to the proposals to produce document clusters; (3) Evaluation and Selection-quantitative and qualitative means were used to evaluate and select an optimal cluster solution. The results of the clustering were then summarized and presented descriptively.

RESULTS

The results of the clustering process identified 24 unique PS and 20 unique SS. The most prevalent PS were Musculoskeletal Injury (12%), Traumatic Injury (11%), and Healthcare Systems Optimization (11%). The most prevalent SS were Sensing and Imaging Technology (27%), Virtual Health (23%), and Physical and Virtual Simulation (11.5%). The most common problem-solution pair was Healthcare Systems Optimization-Virtual Health, followed by Musculoskeletal Injury-Sensing and Imaging Technology. The analysis revealed that problem-solution-set co-occurrences were well distributed throughout the domain space, demonstrating the variety of research conducted in this research domain.

CONCLUSIONS

A semi-supervised document clustering approach was applied to a repository of proposals to partially automate the process of document annotation. By applying this process, we successfully extracted thematic content from the proposals related to problems to be addressed and proposed technological solutions. This analysis provides a snapshot of the research supply in the domain of military medicine over the last 12 years. Future work should seek to replicate and improve the document clustering process used. Future efforts should also be made to compare these results to actual published work in the domain of military medicine, revealing differences in demand for research as determined by funding and publishing decision-makers and supply by researchers.

Quantification of daily workload, energy expenditure, and sleep of US Marine recruits throughout a 10-week boot camp

BACKGROUND

During periods of high-volume vigorous exercise, United States Marine Corps recruits often experience musculoskeletal injuries. While the program of instruction (POI) for basic training is a defined training volume, the total workload of boot camp, including movements around the base, is unknown.

OBJECTIVE

The present study aimed to quantify the daily total workload, energy expenditure, and sleep during basic recruit training at Marine Corps Recruit Depot (MCRD) San Diego.

METHODS

Eighty-four male recruits from MCRD San Diego wore wrist wearable physiological monitors to capture their complete workload (mileage from steps), energy expenditure, and sleep throughout the 10-week boot camp.

RESULTS

Marine recruits traveled an average of 11.5±3.4 miles per day (M±SD), expended 4105±823 kcal per day, and slept an average of 5 : 48±1 : 06 hours and minutes per night. While the POI designates a total of 46.3 miles of running and hiking, the actual daily average miles yielded approximately 657.6±107.2 miles over the 10-week boot camp.

CONCLUSION

Recruit training requires high physical demand and time under tension due to the cumulative volume of movements around base in addition to the POI planned physical training.

Identifying special operative trainees at-risk for musculoskeletal injury using full body kinematics

Introduction: Non-combat musculoskeletal injuries (MSKIs) during military training significantly impede the US military's functionality, with an annual cost exceeding $3.7 billion. This study aimed to investigate the effectiveness of a markerless motion capture system and full-body biomechanical movement pattern assessments to predict MSKI risk among military trainees. Methods: A total of 156 male United States Air Force (USAF) airmen were screened using a validated markerless biomechanics system. Trainees performed multiple functional movements, and the resultant data underwent Principal Component Analysis and Uniform Manifold And Projection to reduce the dimensionality of the time-dependent data. Two approaches, semi-supervised and supervised, were then used to identify at-risk trainees. Results: The semi-supervised analysis highlighted two major clusters with trainees in the high-risk cluster having a nearly five times greater risk of MSKI compared to those in the low-risk cluster. In the supervised approach, an AUC of 0.74 was produced when predicting MSKI in a leave-one-out analysis. Discussion: The application of markerless motion capture systems to measure an individual's kinematic profile shows potential in identifying MSKI risk. This approach offers a novel way to proactively address one of the largest non-combat burdens on the US military. Further refinement and wider-scale implementation of these techniques could bring about substantial reductions in MSKI occurrence and the associated economic costs.

Barriers and facilitators to implementation of musculoskeletal injury mitigation programmes for military service members around the world: a scoping review

INTRODUCTION

Musculoskeletal injury (MSK-I) mitigation and prevention programmes (MSK-IMPPs) have been developed and implemented across militaries worldwide. Although programme efficacy is often reported, development and implementation details are often overlooked, limiting their scalability, sustainability and effectiveness. This scoping review aimed to identify the following in military populations: (1) barriers and facilitators to implementing and scaling MSK-IMPPs; (2) gaps in MSK-IMPP research and (3) future research priorities.

METHODS

A scoping review assessed literature from inception to April 2022 that included studies on MSK-IMPP implementation and/or effectiveness in military populations. Barriers and facilitators to implementing these programmes were identified.

RESULTS

From 132 articles, most were primary research studies (90; 68.2%); the remainder were review papers (42; 31.8%). Among primary studies, 3 (3.3%) investigated only women, 62 (69%) only men and 25 (27.8%) both. Barriers included limited resources, lack of stakeholder engagement, competing military priorities and equipment-related factors. Facilitators included strong stakeholder engagement, targeted programme design, involvement/proximity of MSK-I experts, providing MSK-I mitigation education, low burden on resources and emphasising end-user acceptability. Research gaps included variability in reported MSK-I outcomes and no consensus on relevant surveillance metrics and definitions.

CONCLUSION

Despite a robust body of literature, there is a dearth of information about programme implementation; specifically, barriers or facilitators to success. Additionally, variability in outcomes and lack of consensus on MSK-I definitions may affect the development, implementation evaluation and comparison of MSK-IMPPs. There is a need for international consensus on definitions and optimal data reporting elements when conducting injury risk mitigation research in the military.

Vitamin D levels in Portuguese military personnel

INTRODUCTION

In Portugal, most adults have inadequate levels of vitamin D. Active duty military personnel need to be always ready for duty, perform tasks in specific contexts and overcome high physical and mental demands, which raises the relevance of knowing their vitamin D levels. This study aims to characterise vitamin D levels of Portuguese active duty military personnel and evaluate the effect of military status on the prevalence of vitamin D sufficiency, adjusted for season of the year, age and gender.

METHODS

A retrospective cross-sectional study, based on vitamin D measurements carried out at the Armed Forces Hospital between 2014 and 2020, was fulfilled including the variables age, gender, vitamin D level and dosing date for military personnel and civilians. Comparison of proportions test and the generalised linear regression model were used for data analysis with a significance level of 5%.

RESULTS

Out of 2782 subjects, 62.7% were military personnel. Mean±SD level of vitamin D was 24.5±10.6 ng/mL and 23.7±11.5 ng/mL in military personnel and civilians, respectively. In the military personnel, the prevalence of vitamin D sufficiency, insufficiency and deficiency was, respectively, 25.2%, 40.1% and 34.6%. Prevalence of vitamin D sufficiency was similar in the civilians cohort and, also, between Armed Forces branches. Military status had no effect on the prevalence of vitamin D sufficiency, especially after adjustments.

CONCLUSIONS

We present data on vitamin D levels of Portuguese active duty military personnel. Our results found that military personnel are no more at risk of vitamin D inadequacy than civilians, but only a quarter of active duty military personnel had vitamin D sufficiency. Therefore, they can benefit from vitamin D levels assessment towards vitamin D levels optimisation. Further studies are still needed, especially among military personnel with higher risk of vitamin D deficiency.

Force Health Surveillance in the NATO Does Not Meet the Needs of Its Users: A Structured Evaluation of EpiNATO-2

INTRODUCTION

Disease and non-battle injuries (DNBIs) cause substantial losses among military personnel. NATO has monitored DNBIs among its personnel since 1996 using multiple versions of a tool now called EpiNATO-2, but the surveillance system has never been systematically evaluated. Following a request from NATO to the CDC, the objective of this study was to assess surveillance system attributes of EpiNATO-2 using CDC's updated guidelines for evaluating public health surveillance systems.

MATERIALS AND METHODS

Between June and October 2022, a literature review and key informant interviews were conducted to assess the following attributes: usefulness, simplicity, flexibility, data quality, acceptability, sensitivity, positive predictive value, representativeness, timeliness, stability, informatics system quality, informatics service quality, and informatics interoperability. Key informant interviews were conducted in Kosovo, Germany, and remotely with EpiNATO-2 users spanning three levels: clinical and data entry personnel (tactical level); regional medical and public health officers (operational level); and senior commanders and other governmental entities (strategic level).

RESULTS

Fourteen EpiNATO-2 users participated in interviews, representing 3 of the 5 major NATO missions, 3 partner entities, and 7 nationalities. All users (100%) reported that the system did not meet their needs, with most users noting the following challenges: lack of clearly defined system objectives; poor data quality due to ambiguous case definitions and frequently unsubmitted reports (37% missing during January to June 2022); long delay between the occurrence of health events and the availability of corresponding data (≥2 weeks); and an antiquated and inflexible data management system. Overall, performance was deemed unsatisfactory on 11 of the 13 attributes.

CONCLUSIONS

This multinational sample of EpiNATO-2 users at all military levels reported that the system is currently not useful with respect to its stated objectives. Opportunities exist to improve the performance and usefulness of EpiNATO-2: improve case definitions, modernize data infrastructure, and regularly evaluate the surveillance system.

Pain Catastrophizing and Its Association with Military Medical Disability Among US Active Duty Service Members with Chronic Predominately Musculoskeletal Pain: A Retrospective Cohort Analysis

Context

Pain catastrophizing is characterized by negative emotional and cognitive responses to pain and is a predictor of work-related disability. Its association with military medical disability has not been studied.

Objective

To (1) identify the pain catastrophizing scale (PCS) score cut point most strongly associated with military medical disability, (2) measure the difference in rate of disability between service members with baseline PCS scores above versus below the cut point, and (3) determine if improvement in PCS score during pain specialty care is associated with decreased likelihood of disability.

Methods

This was a retrospective cohort analysis comparing PCS scores collected from US Army active duty service members at time of initial visit to an interdisciplinary pain management center and periodically during pain treatment. Outcome was determination during the following year of a military service-disqualifying disability.

Results

Receiver operating characteristic (ROC) curves determined that a PCS score of 20 was the single cut point most closely associated with subsequent disability. Kaplan-Meier curves showed significantly higher disability rate during the following year among those with baseline PCS scores ≥20 (52%) compared to those with lower scores (26%). Scheffe-adjusted contrasts showed that service members with PCS scores ≥20 whose scores improved to <20 at follow-up were significantly less likely to have a medical disability (42.6%; 95% CI, 0.07-0.58) than those whose PCS score remained ≥20 (76.3%; 95% CI, 68.0%-84.7%).

Conclusion

A PCS score cut point of 20 distinguishes between high versus low likelihood of disability among service members. Those with high baseline PCS score had twice the likelihood of disability than those with low scores. Service members who decreased their PCS score from high to low during pain specialty care had lower likelihood of disability. Prospective research is needed to determine if treatments that lower pain catastrophizing yield reduced likelihood of subsequent disability.

Preliminary Data of Neck Muscle Morphology With Head-Supported Mass in Male and Female Volunteers

INTRODUCTION

This study quantified parameters related to muscle morphology using a group of upright seated female and male volunteers with a head-supported mass.

MATERIALS AND METHODS

Upright magnetic resonance images (MRIs) were obtained from 23 healthy volunteers after approval from the U.S. DoD. They were asymptomatic for neck pain, with no history of injury. The volunteers were scanned using an upright MRI scanner with a head-supported mass (army combat helmet). T1 and T2 sagittal and axial images were obtained. Measurements were performed by an engineer and a neurosurgeon. The cross-sectional areas of the sternocleidomastoid and multifidus muscles were measured at the inferior endplate in the sub-axial column, and the centroid angle and centroid radius were quantified. Differences in the morphology by gender and spinal level were analyzed using a repeated measures analysis of variance model, adjusted for multiple corrections.

RESULTS

For females and males, the cross-sectional area of the sternocleidomastoid muscle ranged from 2.3 to 3.6 cm2 and from 3.4 to 5.4 cm2, the centroid radius ranged from 4.1 to 5.1 cm and from 4.7 to 5.7 cm, and the centroid angle ranged from 75° to 131° and from 4.8° to 131.2°, respectively. For the multifidus muscle, the area ranged from 1.7 to 3.9 cm2 and from 2.4 to 4.2 cm2, the radius ranged from 3.1 to 3.4 cm and from 3.3 to 3.8 cm, the angle ranged from 15° to 24.4° and 16.2° to 24.4°, respectively. Results from all levels for both muscles and male and female spines are given.

CONCLUSIONS

The cross-sectional area, angulation, and centroid radii data for flexor and extensor muscles of the cervical spine serve as a dataset that may be used to better define morphologies in computational models and obtain segmental motions and loads under external mechanical forces. These data can be used in computational models for injury prevention, mitigation, and readiness.

Chronic Pain and Childhood Adversity Experiences Among U.S. Military Personnel

INTRODUCTION

Chronic pain in a military population is prevalent, is costly, and can limit daily activities and affect soldier readiness. It has been associated with childhood adversity (CA) within the veteran, adult, and pediatric populations. Given the need to maximize soldier resiliency, an examination of the link between CA and chronic pain in an active duty population for a better understanding that informs treatment options is warranted.

MATERIALS AND METHODS

The analytic sample comprised 32 men and 8 women drawn from a retrospective review of 203 intake assessments at an interdisciplinary pain management center. We identified a group (CA) of 20 patients who reported a history of pre-adolescent sexual abuse or living in an "abusive" childhood home and compared it with a control group (no-CA) of 20 patients, matched for age, gender, pain history duration, and pain problem. Validated measures were used to assess pain intensity, interference in functioning and well-being, emotional sequelae of pain as reflected in symptoms of depression and anxiety, and pain-related catastrophic thinking. Data were analyzed using descriptive statistics and independent samples t-test analyses.

RESULTS

Differences in current, worst, and average pain ratings were non-significant between groups. The CA group reported significantly greater effect of pain on mood (mean: 6.20 versus 4.25, P < .02) and showed a trend toward higher pain interference in functioning (mean: 17.70 versus 15.05, P = .053). The CA patients had significantly more serious depression (mean: 12.65 versus 4.50, P < .001) and anxiety symptoms (mean: 10.60 versus 2.35, P < .001) and significantly higher pain catastrophizing tendency (mean: 30.05 versus 20.50, P < .03).

CONCLUSIONS

Overall, the findings suggest that childhood trauma should be considered by providers when treating depression and anxiety in soldiers with chronic pain. Being mindful of trauma-informed care may have implications, perhaps, for cases perceived as treatment resistant.

Robust Multi-View Fracture Detection in the Presence of Other Abnormalities Using HAMIL-Net

INTRODUCTION

Foot and ankle fractures are the most common military health problem. Automated diagnosis can save time and personnel. It is crucial to distinguish fractures not only from normal healthy cases, but also robust against the presence of other orthopedic pathologies. Artificial intelligence (AI) deep learning has been shown to be promising. Previously, we have developed HAMIL-Net to automatically detect orthopedic injuries for upper extremity injuries. In this research, we investigated the performance of HAMIL-Net for detecting foot and ankle fractures in the presence of other abnormalities.

MATERIALS AND METHODS

HAMIL-Net is a novel deep neural network consisting of a hierarchical attention layer followed by a multiple-instance learning layer. The design allowed it to deal with imaging studies with multiple views. We used 148K musculoskeletal imaging studies for 51K Veterans at VA San Diego in the past 20 years to create datasets for this research. We annotated each study by a semi-automated pipeline leveraging radiology reports written by board-certified radiologists and extracting findings with a natural language processing tool and manually validated the annotations.

RESULTS

HAMIL-Net can be trained with study-level, multiple-view examples, and detect foot and ankle fractures with a 0.87 area under the receiver operational curve, but the performance dropped when tested by cases including other abnormalities. By integrating a fracture specialized model with one that detecting a broad range of abnormalities, HAMIL-Net's accuracy of detecting any abnormality improved from 0.53 to 0.77 and F-score from 0.46 to 0.86. We also reported HAMIL-Net's performance under different study types including for young (age 18-35) patients.

CONCLUSIONS

Automated fracture detection is promising but to be deployed in clinical use, presence of other abnormalities must be considered to deliver its full benefit. Our results with HAMIL-Net showed that considering other abnormalities improved fracture detection and allowed for incidental findings of other musculoskeletal abnormalities pertinent or superimposed on fractures.

Musculoskeletal Injury Concealment in the Reserve Officers' Training Corps: A Survey of Cadets' Reporting Behaviors

BACKGROUND

Among service members, musculoskeletal injuries threaten military readiness and place a substantial burden on medical and financial resources. Emerging research suggests that service members regularly conceal injuries, especially in training environments. The Reserve Officers' Training Corps (ROTC) is a critical training environment for future U.S. military commissioned officers. Training activities expose cadets to a high risk of injury while in the ROTC. The purpose of this study was to explore injury-reporting behaviors in cadets and factors associated with injury concealment.

MATERIALS AND METHODS

We invited Army, Air Force, and Naval cadets from six host universities participating in officer training to complete an online, self-reported survey regarding injury reporting and concealment. Cadets answered questions about pain or injuries experienced during officer training. Survey questions pertained to an injury's anatomic location, onset, severity, functional limitations, and whether or not the injury had been reported. Cadets also selected factors that influenced the decision to report or conceal injuries from predetermined lists in a "choose any" fashion. A series of χ2 tests of independence compared the relationship between injury reporting and other injury characteristics for each individual injury.

RESULTS

One hundred fifty-nine cadets (121 Army, 26 Air Force, and 12 Naval) completed the survey. Eighty-five cadets disclosed a total of 219 injuries. Two-thirds of injuries (144/219) were concealed. Twenty-six percent of participants (22/85) reported all injuries, whereas the remainder (63/85, 74%) had at least one concealed injury. In relation to injury reporting/concealment, there was a weak association with injury onset (χ21 = 4.24, P = .04, V = 0.14), a moderate association with anatomic location (χ212 = 22.64, P = .03, V = 0.32), and relatively strong associations with injury severity (χ23 = 37.79, P < .001, V = 0.42) and functional limitations (χ23 = 42.91, P < .001, V = 0.44).

CONCLUSIONS

Two-thirds of injuries went unreported in this sample of ROTC cadets. Functional limitations, symptom severity, and injury onset may be the largest factors that influence the decision to report or conceal musculoskeletal injuries. This study establishes the foundation for researching injury reporting in cadets and adds to the existing military evidence on the topic.

Comparison of Health Outcomes Over Time Among Women 1990-1991 Gulf War Veterans, Women 1990-1991 Gulf Era Veterans, and Women in the U.S. General Population

INTRODUCTION

The aim of this study is to examine health over almost 20 years of follow-up among women Gulf War veterans and women Gulf Era veterans and compare their health to that of women in the U.S. general population.

METHODS

We used data from a health survey of 1,274 women Gulf War veteran and Gulf Era veteran participants of the Gulf War Longitudinal Study who responded to all three waves. Data on the U.S. population of women came from the 1999-2000, 2005-2006, and 2011-2014 National Health and Nutrition Examination Survey (NHANES). Generalized estimating equations (GEEs) were used to compare the report of disease over time in women Gulf War and Gulf Era veterans. Differences in prevalence at the three survey timepoints were calculated between women Gulf War veterans and the NHANES women population, and women Gulf War Era veterans and the NHANES women population.

RESULTS

Women veterans who deployed to the 1990-1991 Gulf War report poorer health than women veterans who served during the same time but did not deploy. Women veterans reported a lower prevalence of hypertension, stroke, and diabetes than women in the NHANES sample. Women veterans also reported a higher prevalence of arthritis, chronic obstructive pulmonary disease, and skin cancer than women in the NHANES sample.

CONCLUSIONS

This study is the first to characterize the health of a population-based cohort of women Gulf War and women Gulf Era veterans over time and compare it with women's health in a civilian NHANES population. This demonstrates the value of epidemiological research on women veterans and the importance of developing longitudinal cohorts across genders.

Micro-doppler radar to evaluate risk for musculoskeletal injury: Protocol for a case-control study with gold standard comparison

BACKGROUND

Beyond causing significant morbidity and cost, musculoskeletal injuries (MSKI) are among the most common reasons for primary care visits. A validated injury risk assessment tool for MSKI is conspicuously absent from current care. While motion capture (MC) systems are the current gold standard for assessing human motion, their disadvantages include large size, non-portability, high cost, and limited spatial resolution. As an alternative we introduce the Micro Doppler Radar (MDR); in contrast with MC, it is small, portable, inexpensive, and has superior spatial resolution capabilities. While Phase 1 testing has confirmed that MDR can identify individuals at high risk for MSKI, Phase 2 testing is still needed. Our aims are to 1) Use MDR technology and MC to identify individuals at high-risk for MSKI 2) Evaluate whether MDR has diagnostic accuracy superior to MC 3) Develop MDR algorithms that enhance accuracy and enable automation.

METHODS AND FINDINGS

A case control study will compare the movement patterns of 125 ACL reconstruction patients to 125 healthy controls. This study was reviewed and approved by the Pennsylvania State University Human Research Protection Program (HRPP) on May 18, 2022, and the IRB approval number is STUDY00020118. The ACL group is used as a model for a "high risk" population as up to 24% will have a repeat surgery within 2 years. An 8-camera Motion Analysis MC system with Cortex 8 software to collect MC data. Components for the radar technology will be purchased, assembled, and packaged. A micro-doppler signature projection algorithm will determine correct classification of ACL versus healthy control. Our previously tested algorithm for processing the MDR data will be used to identify the two groups. Discrimination, sensitivity and specificity will be calculated to compare the accuracy of MDR to MC in identifying the two groups.

CONCLUSIONS

We describe the rationale and methodology of a case-control study using novel MDR technology to detect individuals at high-risk for MSKI. We expect this novel approach to exhibit superior accuracy than the current gold standard. Future translational studies will determine utility in the context of clinical primary care.

Impact of mindfulness training and yoga on injury and pain-related impairment: a group randomized trial in basic combat training

Introduction

Service members are at risk for pain-related difficulties in functioning and physical injury. Previous studies suggest that mindfulness training (MT) and yoga may prevent these outcomes. The present study was designed to determine the impact of MT and yoga on the health, pain, and injury of Army trainees completing 10 weeks of basic combat training (BCT).

Methods

Platoons (≈40 trainees per platoon) were randomized to MT and yoga or training-as-usual in October to December 2020 at a large installation in the US. Self-reported outcomes were health, pain level, and pain impact on training, sleep, mood, and stress. Objective outcomes were injury-related medical encounters and number of diagnoses. The trial was registered at ClinicalTrials. Gov (NCT05550610).

Results

Intervention trainees reported significantly better health (OR = 1.05, 95% CI [1.00, 1.10]) and less impact of pain on training (OR = 0.81, 95% CI [0.74, 0.90]), sleep (OR = 0.88, 95% CI [0.81, 0.95]), mood (OR = 0.86, 95% CI [0.78, 0.96]), and stress (OR = 0.88, 95% CI [0.79, 0.98]). There was no significant difference in injury-related medical encounters (AOR = 0.70, 95% CI [0.48, 1.03]), but intervention trainees had fewer diagnoses (OR = 0.67, 95% CI [0.47, 0.95]) and were 30% less likely to have a first medical encounter at any time during BCT. This difference emerged 3 weeks into BCT.

Discussion

A combined MT and yoga intervention resulted in better trainee health. The US Army and other organizations requiring resilience under extreme stress should consider implementing MT and yoga to offset risks to employee health.

Differences in running biomechanics between young, healthy men and women carrying external loads

During U.S. Army basic combat training (BCT), women are more prone to lower-extremity musculoskeletal injuries, including stress fracture (SF) of the tibia, with injury rates two to four times higher than those in men. There is evidence to suggest that the different injury rates are, in part, due to sex-specific differences in running biomechanics, including lower-extremity joint kinematics and kinetics, which are not fully understood, particularly when running with external load. To address this knowledge gap, we collected computed tomography images and motion-capture data from 41 young, healthy adults (20 women and 21 men) running on an instrumented treadmill at 3.0 m/s with loads of 0.0 kg, 11.3 kg, or 22.7 kg. Using individualized computational models, we quantified the running biomechanics and estimated tibial SF risk over 10 weeks of BCT, for each load condition. Across all load conditions, compared to men, women had a significantly smaller flexion angle at the trunk (16.9%-24.6%) but larger flexion angles at the ankle (14.0%-14.7%). Under load-carriage conditions, women had a larger flexion angle at the hip (17.7%-23.5%). In addition, women had a significantly smaller hip extension moment (11.8%-20.0%) and ankle plantarflexion moment (10.2%-14.3%), but larger joint reaction forces (JRFs) at the hip (16.1%-22.0%), knee (9.1%-14.2%), and ankle (8.2%-12.9%). Consequently, we found that women had a greater increase in tibial strain and SF risk than men as load increases, indicating higher susceptibility to injuries. When load carriage increased from 0.0 kg to 22.7 kg, SF risk increased by about 250% in women but only 133% in men. These results provide quantitative evidence to support the Army's new training and testing doctrine, as it shifts to a more personalized approach that shall account for sex and individual differences.

Sex disparities in self-reported musculoskeletal injuries in the Canadian Armed Forces

Recent comprehensive systematic reviews indicate that females are at greater risk of musculoskeletal injuries (MSKi) than males in military populations. Considering the Canadian Armed Forces (CAF) goal of increasing female representation in the next few years, exploring these trends is essential. We aimed to determine the association between biological sex and MSKi in the CAF. An online survey was conducted with active-duty and former CAF members aged 18-65 years. Sex disparities in MSKi (acute or repetitive strain [RSI]) were analyzed using bivariate associations and binary logistic regressions with significance level at p < 0.05. Analyses were stratified by military environment (i.e., Army, Navy, and Air Force). From the 1947 respondents whose biological sex was reported, 855 were females and 1092 were males. Rates of RSI sustained by females and males while serving were 76.2% and 70.5% (p = 0.011), respectively, whereas 61.4% of females reported acute injuries compared to 63.7% of males (p = 0.346). Females were more likely to report overall RSI (adjusted odds ratio [aOR]: 1.397; 95% confidence intervals [CI]: 1.068-1.829), RSI having a greater impact on daily activities (aOR [95%CI]: 2.979 [2.093-4.239]) and greater impact on career progress/length (aOR [95%CI]: 1.448 [1.066-1.968]). Acute injuries, also more prevalent in females, were reported to have a greater impact on daily activities (aOR [95%CI]: 1.688 [1.198-2.379]). This study highlights sex disparities in MSKi prevalence and outcomes. Females within the CAF sample presented greater likelihood of reporting RSI, perceived impact of RSI on daily activities and career progress/length, and perceived impact of acute injuries on daily activities.

Non-traditional HIIT-style ROTC training elicits positive bone quality and performance adaptations

Military personnel experience elevated bone injury incidence, partly due to arduous and repetitive training. Non-traditional High-Intensity Interval Training-style (HIIT) may benefit pre-enlisted Reserve Officer Training Corps (ROTC) cadet's musculoskeletal health and performance prior to military service. This study investigated 16 ROTC (n = 12 males; n = 4 females) and 15 physically active sex-, age-, and body mass-matched Controls' musculoskeletal health and performance from November to April. Total body, lumbar spine, and dual- hip dual-energy X-ray absorptiometry scans and 4%, 38%, 66% tibial peripheral quantitative computed tomography scans, blood draws (serum sclerostin and parathyroid hormone), and maximal muscle strength and aerobic capacity testing were completed. From November to April, ROTC improved bone density (DXA) of the dominant total hip and greater trochanter and non-dominant greater trochanter and 38% and 66% tibial total volumetric and cortical bone density (pQCT) similarly or more than Controls (all p ≤ 0.049). From November to April, ROTC also improved bench and leg press, and peak aerobic capacity (all p ≤ 0.013). From November to January, serum sclerostin increased (p ≤ 0.007) and remained elevated through April, while parathyroid hormone was unchanged. HIIT-style training induced positive musculoskeletal adaptations, suggesting it may be an excellent pre-service training modality for this injury prone group.

Low-volume Hydrodissection for the Treatment of Chronic Achilles Tendinopathy

Chronic Achilles tendinopathy (AT) is a common ailment for many active duty service members that adversely affects readiness. Patients present with pain, swelling, and limited functional ability. Kager's fat pad is a mass of adipose tissue that protects the blood vessels supplying the Achilles tendon and preserves its function. A popular hypothesis is that scarring, tethering, and neovascularization play a significant role in the pathogenesis of AT. Current literature supports the effectiveness of high-volume (40-50 mL) hydrodissection, a procedure in which fluid is injected under ultrasound guidance into the tissues surrounding the Achilles tendon to mechanically separate the paratenon from the underlying Kager's fat pad. There may also be a beneficial effect of scar tissue and neoneurovascular breakdown. However, high-volume injections result in short-term discomfort and decreased mobility. Lowering injection volume (2-10 mL) may reduce this morbidity and facilitate use in limited-resource environments. This case report presents a 29-year-old active duty male with recalcitrant post-traumatic AT who achieved significant pain reduction and faster return to full service using low-volume hydrodissection. The use of 10 mL volume has not been described previously and provides additional support for using lower volumes in chronic AT. This technique is a direct adjunctive treatment option with rehabilitation at a military treatment facility or in the operational environment.

The combined effects of coping and pain interference on army readiness

Introduction

Chronic pain and associated interference with daily activities are common in the military and impact Force readiness. Chronic pain affects one-third of service members and is a leading cause of medical non-readiness (MNR) in the military. Research suggests that underlying psychological mechanisms related to trait coping styles and pain interference (PI) affect functional outcomes, but little research exists examining this relationship within an Army population. The purpose of this study was to examine the combined effects of PI and coping on U.S. Army soldier readiness by using annual well-being data from the Global Assessment Tool (GAT) and medical non-readiness (MNR) based on duty restriction records.

Methods

The sample comprised 866,379 soldiers who completed the GAT between 2014 and 2017 with no duty restrictions at the time of baseline GAT completion; subjects were observed through 2018 for duty restrictions. Parametric survival regression models with a Weibull distribution predicted demographic-adjusted hazards of MNR by dichotomized PI (no PI/PI) and beneficial/non-beneficial use of GAT coping components (good coping, bad coping, catastrophizing-flexibility, and catastrophizing-hopelessness). Incident MNR was evaluated for all duty restrictions, and stratified by selected body systems (upper extremity, lower extremity, psychiatric).

Results

Among soldiers with PI, hazards were higher in those reporting non-beneficial coping styles (bad coping, hopelessness) and lower in those reporting beneficial coping styles (good coping, flexibility). Across all coping styles, PI/coping interactions were particularly strong for catastrophizing-hopelessness and when examining MNR from psychiatric conditions.

Discussion

These findings suggest some synergistic associations between pain and coping that may impact pain-related occupational disability. Coping skills may be an effective interventional target for chronic pain reduction/prevention within military programs, such as the Master Resilience Training Course offered to soldiers in the Army. Further research should assess whether early coping style interventions can reduce pain-related outcomes.

Risk factors for musculoskeletal-related occupational disability among US Army soldiers

INTRODUCTION

Minimising temporary and permanent disability associated with musculoskeletal conditions (MSK-D) is critical to the mission of the US Army. Prior research has identified potentially actionable risk factors for overall military disability and its MSK-D subset, including elevated body mass index, tobacco use and physical fitness. However, prior work does not appear to have addressed the impact of these factors on MSK-D when controlling for a full range of factors that may affect health behaviours, including aptitude scores that may serve as a proxy for health literacy. Identifying risk factors for MSK-D when providing control for all such factors may inform efforts to improve military readiness.

METHODS

We studied 494 757 enlisted Army soldiers from 2014 to 2017 using a combined medical and administrative database. Leveraging data from the Army's digital 'eProfile' system of duty restriction records, we defined MSK-D as the first restriction associated with musculoskeletal conditions and resulting in the inability to deploy or train. We used multivariable Cox proportional hazards regression to assess the associations between incident MSK-D and selected risk factors including aptitude scores, physical fitness test scores, body mass index and tobacco use.

RESULTS

Among the subjects, 281 278 (45.14%) experienced MSK-D. In the MSK-D hazards model, the highest effect size was for failing the physical fitness test (adjusted HR=1.63, 95% CI 1.58 to 1.67, p<0.001) compared with scoring ≥290 points.

CONCLUSIONS

The analysis revealed the strongest associations between physical fitness and MSK-D. Additional efforts are warranted to determine potential mechanisms for the observed associations between selected factors and MSK-D.

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. and U.K. military operational research efforts are supporting a science-based evolution of physical training and standards for female warfighters. The increasing representation of women in all military occupations makes it possible to discover and document the limits of female physiological performance.

METHOD

An informal Delphi process was used to synthesize an integrated concept of current military female physiological research priorities and emerging findings using a panel of subject matter experts who presented their research and perspectives during the second Women in Combat Summit hosted by the TriService Nursing Research Program in February 2021.

RESULTS

The physical characteristics of the modern soldier are changing as women train for nontraditional military roles, and they are emerging as stronger and leaner. Capabilities and physique will likely continue to evolve in response to new Army standards and training programs designed around science-based sex-neutral requirements. Strong bones may be a feature of the female pioneers who successfully complete training and secure roles traditionally reserved for men. Injury risk can be reduced by smarter, targeted training and with attention directed to female-specific hormonal status, biomechanics, and musculoskeletal architecture. An "estrogen advantage" appears to metabolically support enhanced mental endurance in physically demanding high-stress field conditions; a healthy estrogen environment is also essential for musculoskeletal health. The performance of female soldiers can be further enhanced by attention to equipment that serves their needs with seemingly simple solutions such as a suitable sports bra and personal protective equipment that accommodates the female anatomy.

CONCLUSIONS

Female physiological limits and performance have yet to be adequately defined as women move into new roles that were previously developed and reserved for men. Emerging evidence indicates much greater physical capacity and physiological resilience than previously postulated.

Sex differences in musculoskeletal injury epidemiology and subsequent loss of tactical readiness during Marine Corps Officer Candidates School

INTRODUCTION

The US Marine Corps (USMC) Officer Candidates School (OCS) is a 10-week training course for Marine Officer Candidates (MOCs). OCS training is rigorous and demanding, which results in a high risk of musculoskeletal injuries (MSIs). The objective of this analysis was to describe MSIs among women and men during the USMC OCS at Quantico, Virginia, from September 2020 to November 2021.

METHODS

This prospective cohort study assessed MSIs that occurred among 736 MOCs (women: 17.8% of sample, men: 82.2%). Data for the study were derived from routinely collected injury data by athletic trainers and physical therapists embedded within the training units. Injury incidence, event at the time of injury occurrence, anatomic location, injury type and disposition following injury were described. Fisher's exact tests were used to compare proportions of injured women and men.

RESULTS

The cumulative injury incidence was higher among women (39.7%) compared with men (23.1%, p<0.001). When specific events associated with injuries were reported, most frequent events were the obstacle course (women: 20.9% of injuries, men: 12.9%) and the conditioning hike (women: 11.6%, men: 6.9%). Most injures affected the lower body (women: 67.4%, men: 70.8%). The most frequent body part injured was the lower leg (18.6%) in women and the knee (23.3%) in men. The most frequent injury type was strain (women: 39.5%, men: 24.3%), followed by sprain (women: 16.3%, men: 14.9%). A greater percentage of female (92.3%) compared with male MOCs (69.3%; p<0.001) were assigned light duty status following MSIs.

CONCLUSIONS

Mitigation of injuries during OCS events such as the obstacle course and the conditioning hike needs further investigation. The high risk of overuse lower leg injuries among women and the higher incidence of injuries among women compared with men underscore the need for further investigation of modifiable sex-specific injury risk factors.

Musculoskeletal Injury Risk Stratification: A Traffic Light System for Military Service Members

Risk factor identification is a critical first step in informing musculoskeletal injury (MSKI) risk mitigation strategies. This investigation aimed to determine if a self-reported MSKI risk assessment can accurately identify military service members at greater MSKI risk and determine whether a traffic light model can differentiate service members' MSKI risks. A retrospective cohort study was conducted using existing self-reported MSKI risk assessment data and MSKI data from the Military Health System. A total of 2520 military service members (2219 males: age 23.49 ± 5.17 y, BMI 25.11 ± 2.94 kg/m²; and 301 females: age 24.23 ± 5.85 y, BMI 25.59 ± 3.20 kg/m², respectively) completed the MSKI risk assessment during in-processing. The risk assessment consisted of 16 self-report items regarding demographics, general health, physical fitness, and pain experienced during movement screens. These 16 data points were converted to 11 variables of interest. For each variable, service members were dichotomized as at risk or not at risk. Nine of the 11 variables were associated with a greater MSKI risk and were thus considered as risk factors for the traffic light model. Each traffic light model included three color codes (i.e., green, amber, and red) to designate risk (i.e., low, moderate, and high). Four traffic light models were generated to examine the risk and overall precision of different cut-off values for the amber and red categories. In all four models, service members categorized as amber [hazard ratio (HR) = 1.38-1.70] or red (HR = 2.67-5.82) were at a greater MSKI risk. The traffic light model may help prioritize service members who require individualized orthopedic care and MSKI risk mitigation plans.

Financial Impact of Embedded Injury-Prevention Experts in US Army Initial Entry Training

CONTEXT

The US Army embedded injury-prevention experts (IPEs), specifically athletic trainers and strength and conditioning coaches, into initial entry training (IET) to limit musculoskeletal (MSK) conditions and their negative consequences. However, little is known about the financial impact of IPEs.

OBJECTIVE

To assess whether IPEs were associated with fewer sunk training costs due to MSK-related early discharges from service.

DESIGN

Retrospective cohort study.

SETTING

Database of US Army soldiers' administrative, medical, and readiness records.

PATIENTS OR OTHER PARTICIPANTS

A total of 198 166 soldiers (age = 20.7 ± 3.2 years, body mass index = 24.4 ± 3.5 kg/m2) who began IET during 2014 to 2017.

MAIN OUTCOME MEASURE(S)

Early discharge from service was defined as occurring within 6 months of beginning IET. All IET sites employed IPEs from 2011 to 2017, except for 2 sites during April to November 2015. Soldiers who began IET at these 2 sites during these times were categorized as not having IPE exposure. All others were categorized as having IPE exposure. The unadjusted association between IPE access and MSK-related early discharge from service was assessed using logistic regression. Financial impact was assessed by quantifying differences in yearly sunk costs between groups with and those without IPE exposure and subtracting IPE hiring costs.

RESULTS

Among 14 094 soldiers without IPE exposure, 2.77% were discharged early for MSK-related reasons. Among 184 072 soldiers with IPE exposure, 1.01% were discharged. Exposure to IPEs was associated with reduced odds of MSK-related early discharge (odds ratio = 0.36, 95% CI = 0.32, 0.40, P < .001) and a decrease in yearly sunk training costs of $11.19 to $20.00 million.

CONCLUSIONS

Employing IPEs was associated with reduced sunk costs because of fewer soldiers being discharged from service early for MSK-related reasons. Evidence-based recommendations should be developed for guiding policy on the roles and responsibilities of IPEs in the military to reduce negative outcomes from MSK conditions and generate a positive return on investment.

Wearable technology assessing running biomechanics and prospective running-related injuries in Active Duty Soldiers

The purpose of this study was to determine if running biomechanical variables measured by wearable technology were prospectively associated with running injuries in Active Duty Soldiers. A total of 171 Soldiers wore a shoe pod that collected data on running foot strike pattern, step rate, step length and contact time for 6 weeks. Running-related injuries were determined by medical record review 12 months post-study enrollment. Differences in running biomechanics between injured and non-injured runners were compared using independent t-tests or ANCOVA for continuous variables and chi-square analyses for the association of categorical variables. Kaplan-Meier survival curves were used to estimate the time to a running-related injury. Risk factors were carried forward to estimate hazard ratios using Cox proportional hazard regression models. Forty-one participants (24%) sustained a running-related injury. Injured participants had a lower step rate than non-injured participants, but step rate did not have a significant effect on time to injury. Participants with the longest contact time were at a 2.25 times greater risk for a running-related injury; they were also relatively slower, heavier, and older. Concomitant with known demographic risk factors for injury, contact time may be an additional indicator of a running-related injury risk in Active Duty Soldiers.

Maintaining soldier musculoskeletal health using personalised digital humans, wearables and/or computer vision

OBJECTIVES

The physical demands of military service place soldiers at risk of musculoskeletal injuries and are major concerns for military capability. This paper outlines the development new training technologies to prevent and manage these injuries.

DESIGN

Narrative review.

METHODS

Technologies suitable for integration into next-generation training devices were examined. We considered the capability of technologies to target tissue level mechanics, provide appropriate real-time feedback, and their useability in-the-field.

RESULTS

Musculoskeletal tissues' health depends on their functional mechanical environment experienced in military activities, training and rehabilitation. These environments result from the interactions between tissue motion, loading, biology, and morphology. Maintaining health of and/or repairing joint tissues requires targeting the "ideal" in vivo tissue mechanics (i.e., loading and strain), which may be enabled by real-time biofeedback. Recent research has shown that these biofeedback technologies are possible by integrating a patient's personalised digital twin and wireless wearable devices. Personalised digital twins are personalised neuromusculoskeletal rigid body and finite element models that work in real-time by code optimisation and artificial intelligence. Model personalisation is crucial in obtaining physically and physiologically valid predictions.

CONCLUSIONS

Recent work has shown that laboratory-quality biomechanical measurements and modelling can be performed outside the laboratory with a small number of wearable sensors or computer vision methods. The next stage is to combine these technologies into well-designed easy to use products.

The Utility of Myotonometry in Musculoskeletal Rehabilitation and Human Performance Programming

Myotonometry is a relatively novel method used to quantify the biomechanical and viscoelastic properties (stiffness, compliance, tone, elasticity, creep, and mechanical relaxation) of palpable musculotendinous structures with portable mechanical devices called myotonometers. Myotonometers obtain these measures by recording the magnitude of radial tissue deformation that occurs in response to the amount of force that is perpendicularly applied to the tissue through a device's probe. Myotonometric parameters such as stiffness and compliance have repeatedly demonstrated strong correlations with force production and muscle activation. Paradoxically, individual muscle stiffness measures have been associated with both superior athletic performance and a higher incidence of injury. This indicates optimal stiffness levels may promote athletic performance, whereas too much or too little may lead to an increased risk of injury. Authors of numerous studies suggested that myotonometry may assist practitioners in the development of performance and rehabilitation programs that improve athletic performance, mitigate injury risk, guide therapeutic interventions, and optimize return-to-activity decision-making. Thus, the purpose of our narrative review was to summarize the potential utility of myotonometry as a clinical tool that assists musculoskeletal clinicians with the diagnosis, rehabilitation, and prevention of athletic injuries.

Subjective Measures of Workload and Sleep in Australian Army Recruits; Potential Utility as Monitoring Tools

INTRODUCTION

Subjective measures may offer practitioners a relatively simple method to monitor recruit responses to basic military training (BMT). Yet, a lack of agreement between subjective and objective measures may presents a problem to practitioners wishing to implement subjective monitoring strategies. This study therefore aims to examine associations between subjective and objective measures of workload and sleep in Australian Army recruits.

MATERIALS AND METHODS

Thirty recruits provided daily rating of perceived exertion (RPE) and differential RPE (d-RPE) for breathlessness and leg muscle exertion each evening. Daily internal workloads determined via heart rate monitors were expressed as Edwards training impulse (TRIMP) and average heart rate. External workloads were determined via global positioning system (PlayerLoadTM) and activity monitors (step count). Subjective sleep quality and duration was monitored in 29 different recruits via a customized questionnaire. Activity monitors assessed objective sleep measures. Linear mixed-models assessed associations between objective and subjective measures. Akaike Information Criterion assessed if the inclusion of d-RPE measures resulted in a more parsimonious model. Mean bias, typical error of the estimate (TEE) and within-subject repeated measures correlations examined agreement between subjective and objective sleep duration.

RESULTS

Conditional R2 for associations between objective and subjective workloads ranged from 0.18 to 0.78, P < 0.01, with strong associations between subjective measures of workload and TRIMP (0.65-0.78), average heart rate (0.57-0.73), and PlayerLoadTM (0.54-0.68). Including d-RPE lowered Akaike Information Criterion. The slope estimate between objective and subjective measures of sleep quality was not significant. A trivial relationship (r = 0.12; CI -0.03, 0.27) was observed between objective and subjective sleep duration with subjective measures overestimating (mean bias 25 min) sleep duration (TEE 41 min).

CONCLUSIONS

Daily RPE offers a proxy measure of internal workload in Australian Army recruits; however, the current subjective sleep questionnaire should not be considered a proxy measure of objective sleep measures.