Evaluating the impact of a combined aerobic and strength training intervention on the physical performance of male Chinese People's Liberation Army air force pilots

This study aimed to assess the impact of a 16-week combined training program on the physical performance of 20 male Air Force pilots, with an average age of 31.87 ± 2.75 years, body mass of 76.33 ± 0.79 kg, and height of 175.55 ± 3.65 cm. This intervention encompassed both aerobic and strength training, involving six weekly training sessions. The participants were categorized into two groups based on their initial physical performance levels to explore potential baseline influences on post-intervention adaptations. The study measured changes in estimated maximal oxygen uptake (VO2 max), maximal strength, muscular endurance, and long jump performance before and after the training program. Repeated measures ANOVA revealed significant differences over time in theV ˙ O2 max (F = 86.898; p < 0.001;η p 2  = 0.821), handgrip strength right hand (F = 160.480; p < 0.001;η p 2  = 0.894), handgrip strength left hand (F = 102.196; p < 0.001;η p 2  = 0.843), squat maximal strength (F = 525.725; p < 0.001;η p 2  = 0.965), push-ups (F = 337.197; p < 0.001;η p 2  = 0.974), sit up (F = 252.500; p < 0.001;η p 2  = 0.930) and standing long jump (F = 521.714; p < 0.001;η p 2  = 0.965). In conclusion, the 16-week combined training regimen significantly enhanced the physical performance of Air Force pilots, regardless of their initial performance levels.

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.

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.

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.

Selection, Initiation, Continuation, and Efficacy of Reversible Contraception Among Enlisted U.S. Service Women in Their First Term of Service From 2012 to 2020

BACKGROUND

Pregnancy is the second most common cause of limited duty days among active duty service members in the U.S. Military. Pregnancy accounts for 10% of all days on restricted duty, despite impacting a minority of active duty service members. One out of five service women will experience an unintended pregnancy every year despite the availability of no-cost contraception and reproductive healthcare. Young, single, junior enlisted service women experience the highest rate of unintentional pregnancy. Previous studies have demonstrated service branch-based variability in selection, initiation, and continuation of specific contraceptive methods related to service branch culture and access to contraception during basic training. It is unclear if these differences impact overall contraception use or fertility rates among junior enlisted service women in their first term of enlistment. This study examines rates of contraceptive selection, initiation, continuation, and efficacy among junior enlisted service women in their first 4-year enlistment period, and the service branch specific variability in these outcomes.

METHODS

This study is a secondary analysis of Military Healthcare Data Repository records from women who began basic training between 2012 and 2020 and remained on active duty for at least 12 months. We used Kaplan-Meier analyses to examine the effect of age and military branch on contraceptive continuation and efficacy. We used binomial regression for interval censored data, to assess the association of service branch with rates of contraceptive initiation, contraception use, births, and childbirth-related duty restrictions.

RESULTS

We identified 147,594 women who began basic training between 2012 and 2020. The mean age of these women at the beginning of basic training was 20.4 ± 3.1 years. Women in the marines and navy had higher contraceptive initiation rates than women in the army or air force. Among women initiating a contraceptive pill, patch, or ring (short-acting reversible contraception), 58.3% were still using some form of hormonal contraception 3 months later. Among women initiating depot-medroxyprogesterone (DMPA), 38.8% were still using any form of hormonal contraception 14 weeks later. Long-acting reversible contraceptive methods, such as intrauterine or subdermal contraceptives, had higher continuation rates and less service-based variability in continuation and failure rates than short-acting reversible contraception or depot-medroxyprogesterone. The proportion of days on any form of prescription contraception during the first 4 years on active duty varied from 23.3% in the army to 38.6% in the navy. The birth rate varied from 34.8 births/1,000 woman-years in the air force up to 62.7 births/1,000 woman-years in the army. Compared with women in the air force, women in the army experienced 2,191 additional days of postpartum leave and 13,908 days on deployment restrictions per 1,000 woman-years.

DISCUSSION

Service branch specific variability in contraceptive use is associated with differences in days of pregnancy-related duty restrictions during first 4 years on active duty among junior enlisted females. Robust implementation of best practices in contraceptive care across the military health system to improve contraceptive initiation and continuation appears to offer an opportunity to improve military readiness and promote the health and well-being of active duty service women, particularly in the army.

Physically Active Adults with Low Back Pain do not Demonstrate Altered Deadlift Mechanics: A Novel Application of Myotonometry to Estimate Inter-Muscular Load Sharing

Background

Rehabilitation clinicians that work with physically active populations are challenged with how to safely return patients back to performing deadlift movements following low back injury. Application of reliable and valid tests and measures to quantify impairments related to low back pain (LBP) enhances clinical decision making and may affect outcomes. Myotonometry is a non-invasive method to assess muscle stiffness which has demonstrated significant associations with physical performance and musculoskeletal injury.

Hypothesis/Purpose

The purpose of this study was to compare the stiffness of trunk (lumbar multifidus [LM] and longissimus thoracis [LT]) and lower extremity (vastus lateralis [VL] and biceps femoris [BF]) muscles between individuals with and without LBP during the lying, standing, and deadlifting body positions.

Study Design

Cross-sectional cohort comparison.

Methods

Muscle stiffness measures were collected in the VL, BF, LM, and LT muscles with participants in lying (supine and prone), standing, and the trap bar deadlift position. Separate analyses of covariance were conducted to compare absolute and relative muscle stiffness between the groups for each muscle and condition.

Results

Sixty-eight participants (41 female, 21.3 years, 34 LBP) volunteered for the study. Within the deadlift condition there was a significantly greater increase in the percent-muscle stiffness change in the VL (p = .029, 21.9%) and BF (p = .024, 11.2%) muscles in the control group than in the LBP group. There were no differences in percent-muscle stiffness changes for the standing condition nor were there any absolute muscle stiffness differences between the two groups for the three conditions.

Conclusion

No differences in muscle stiffness were identified in the lying, standing, or deadlifting conditions between participants with and without LBP. Differences in percent stiffness changes were noted between groups for the deadlift position, however the differences were modest and within measurement error. Future studies should investigate the utility of myotonometry as a method to identify LBP-related impairments that contribute to chronic and/or recurrent low back injury.

Level of Evidence

Level 3.

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.

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.

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.

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.

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.

Universal Training Precautions: A Review of Evidence and Recommendations for Prevention of Exercise-Related Injury, Illness, and Death in Warfighters and Athletes

Facing pressure to train for victory, warfighters and athletes encounter numerous health risks that are directly related to their regular physical training. The concept of universal training precautions (UTPs) signifies universal processes designed to prevent unnecessary bodily harm, including injury, illness, and death, during physical training programs. Although no formal guidelines exist for collectively implementing a defined set of UTPs to address a broad scope of exercise-related health risks, recommendations and guidelines have been published relating to preventing sudden death during high school sports and collegiate conditioning sessions. A long list of critical topics must be considered as UTPs, including physical fitness factors, transition-period accommodation, hydration, environmental factors and acclimatization, appropriate recovery, use of medications and dietary supplements, and importantly, leadership. In this article, we outline in detail, with corresponding Strength of Recommendation Taxonomy ratings, what should be considered universal recommendations to minimize the risk of warfighters and athletes coming to harm when participating in group physical activities.

Gender data gap in military research: a review of the participation of men and women in military musculoskeletal injury studies

Servicewomen are at increased risk of musculoskeletal injuries compared with their male counterparts, but women are under-represented in sports medicine research. The aim of this review was to assess the representation of women in military musculoskeletal injury studies. PubMed was searched for human original research studies using the terms Military OR Army OR Navy OR 'Air Force' AND 'musculoskeletal injury' Each study was categorised as epidemiology (basic training), epidemiology (trained personnel), risk factors, interventions and other. The number of male and female participants was retrieved from each study. A total of 262 studies were included: 98 (37%) studies only included men, 17 (6%) studies only included women and 147 (56%) studies included both men and women. A total of 8 051 778 participants were included in these studies (men: 6 711 082, 83%; women: 1 340 696, 17%). The study theme with the greatest proportion of women was musculoskeletal injury epidemiology studies in a basic training population (20% of participants) with the lowest proportion of women in intervention trials (6% of participants). These data suggest women are not under-represented in military musculoskeletal injury studies when considering the gender representation of most militaries. Our data are, however, biased by large epidemiological trials and women were under-represented in intervention trials. The under-representation of women in intervention trials could be due to difficulties in controlling for the effects of female sex steroids on musculoskeletal outcomes, or a focus on interventions in the most arduous military roles where injury risk is highest and women have been previously excluded.

Predictive utility of commercial grade technologies for assessing musculoskeletal injury risk in US Marine Corps Officer candidates

Recently, commercial grade technologies have provided black box algorithms potentially relating to musculoskeletal injury (MSKI) risk and functional movement deficits, in which may add value to a high-performance model. Thus, the purpose of this manuscript was to evaluate composite and component scores from commercial grade technologies associations to MSKI risk in Marine Officer Candidates. 689 candidates (Male candidates = 566, Female candidates = 123) performed counter movement jumps on SPARTA™ force plates and functional movements (squats, jumps, lunges) in DARI™ markerless motion capture at the start of Officer Candidates School (OCS). De-identified MSKI data was acquired from internal OCS reports for those who presented to the Physical Therapy department for MSKI treatment during the 10 weeks of training. Logistic regression analyses were conducted to validate the utility of the composite scores and supervised machine learning algorithms were deployed to create a population specific model on the normalized component variables in SPARTA™ and DARI™. Common MSKI risk factors (cMSKI) such as older age, slower run times, and females were associated with greater MSKI risk. Composite scores were significantly associated with MSKI, although the area under the curve (AUC) demonstrated poor discrimination (AUC = .55-.57). When supervised machine learning algorithms were trained on the normalized component variables and cMSKI variables, the overall training models performed well, but when the training models were tested on the testing data the models classified MSKI "by chance" (testing AUC avg = .55-.57) across all models. Composite scores and component population specific models were poor predictors of MSKI in candidates. While cMSKI, SPARTA™, and DARI™ models performed similarly, this study does not dismiss the use of commercial technologies but questions the utility of a singular screening task to predict MSKI over 10 weeks. Further investigations should evaluate occupation specific screening, serial measurements, and/or load exposure for creating MSKI risk models.

Physical Injuries, Treatment-Seeking, and Perceived Barriers to Treatment in U.S. Army Drill Sergeants

INTRODUCTION

Drill sergeants work under mentally and physically challenging conditions. The current study examined self-reported rates of physical injuries in drill sergeants; rates of treatment-seeking for injuries; perceived barriers toward treatment-seeking; and associated demographic and environmental factors.

MATERIALS AND METHODS

Drill sergeants from across all Army basic training locations completed self-report surveys from September to November of 2018. In total, 726 drill sergeants were included in analyses. Drill sergeants indicated whether they had acquired an injury during their time in the drill sergeant role and whether they had sought treatment for all such injuries. Furthermore, drill sergeants rated their agreement with a number of possible perceived barriers to treatment-seeking for physical injuries. Regression models examining each phenomenon included hours of sleep obtained per day; general- and health-specific leadership behaviors of the company command teams; unit cohesion; time as a drill sergeant; duty location; gender; military operational specialty; years in the military; previous combat deployments; and route of assignment. The study was approved by the Walter Reed Army Institute of Research Institutional Review Board.

RESULTS

In total, 38% of respondents reported acquiring an injury during their time as drill sergeants. Of those who had acquired an injury, 61% reported seeking medical help for all injuries acquired. Injuries were more likely in females (49%) than in males (34%) and less likely in drill sergeants reporting at least 6 hours of sleep (27%) versus those reporting 5 hours (40%) and 4 hours or less (43%). Reported comparisons were significant after controlling for demographic and environmental variables in regression models. The most strongly endorsed perceived barriers to treatment-seeking were "Seeking help would place too much burden on the other drill sergeants" (69%) and "Seeking help would interfere with my ability to train the recruits" (60%). Both of these perceived barriers were significantly associated with reduced treatment-seeking in injured drill sergeants, after controlling for demographic and environmental variables.

CONCLUSIONS

This study is the first to examine injury occurrence, treatment-seeking, and perceived barriers to treatment-seeking in U.S. Army drill sergeants. Building on previous studies that showed the negative effects of sleep deprivation on the safety and behavioral health of drill sergeants, the current study gives further evidence of the negative effects of such sleep deprivation, this time in the domain of physical injuries. The results suggest that pursuing strategies that allow for healthier sleep duration may contribute to injury reduction.

Biomechanical and Psychological Predictors of Failure in the Air Force Physical Fitness Test

Physical fitness is a pillar of U.S. Air Force (USAF) readiness and ensures that Airmen can fulfill their assigned mission and be fit to deploy in any environment. The USAF assesses the fitness of service members on a periodic basis, and discharge can result from failed assessments. In this study, a 21-feature dataset was analyzed related to 223 active-duty Airmen who participated in a comprehensive mental and social health survey, body composition assessment, and physical performance battery. Graphical analysis revealed pass/fail trends related to body composition and obesity. Logistic regression and limited-capacity neural network algorithms were then applied to predict fitness test performance using these biomechanical and psychological variables. The logistic regression model achieved a high level of significance (p < 0.01) with an accuracy of 0.84 and AUC of 0.89 on the holdout dataset. This model yielded important inferences that Airmen with poor sleep quality, recent history of an injury, higher BMI, and low fitness satisfaction tend to be at greater risk for fitness test failure. The neural network model demonstrated the best performance with 0.93 accuracy and 0.97 AUC on the holdout dataset. This study is the first application of psychological features and neural networks to predict fitness test performance and obtained higher predictive accuracy than prior work. Accurate prediction of Airmen at risk of failing the USAF fitness test can enable early intervention and prevent workplace injury, absenteeism, inability to deploy, and attrition.

Test-Retest Reliability and Translation of the Musculoskeletal Screening Protocol Questionnaire Used in the Swedish Armed Forces

INTRODUCTION

Musculoskeletal disorders (MSDs) in military personnel are common, and it is important to identify those at risk so that appropriate preventive and rehabilitative strategies can be undertaken. The Musculoskeletal Screening Protocol (MSP) questionnaire is part of the implemented prevention strategy to reduce MSDs in the Swedish Armed Forces. The aims of this study were to evaluate the questionnaire's reliability and to translate it into English.

MATERIALS AND METHODS

One-week test-retest reliability of the questionnaire was evaluated in a sample of 35 Swedish military personnel. Reliability was evaluated by calculations of Cohen's kappa or quadratic-weighted kappa. Percent agreement was used as a parameter for measurement error. Translation into English included forward and backward translations and expert committee discussions.

RESULTS

Kappa values relating to physical complaints/injuries were excellent (>0.75) except for knee and lower leg MSDs and for the intensity ratings, where Kappa values were mostly interpreted as fair-to-good (0.4-0.75). Kappa values of items pertaining physical performance, physical activity and exercise, eating and tobacco habits, sleep, and perceived health ranged between 0.72 and 1. Kappa values for feeling mentally or physical prepared were 0.47 and 0.65, respectively. Most percentage agreement values ranged between 90% and 100%. The English version was found to be satisfactorily equivalent to the Swedish MSP questionnaire.

CONCLUSION

The Swedish MSP questionnaire was found to be highly reliable and was satisfactorily translated into English. This provides support for the questionnaire's ability to trustworthily capture the prevalence of MSDs and perceived health in military personnel. Future research is warranted on the psychometric properties of the English MSP questionnaire.

Utilization of the Department of Defense Peer-Reviewed Orthopaedic Research Program (PRORP): Combating Musculoskeletal Disease With PRORP

INTRODUCTION

Established in 2009, the Department of Defense (DoD) Peer-Reviewed Orthopaedic Research Program (PRORP) is an annual funding program for orthopaedic research that seeks to develop evidence for new clinical practice guidelines, procedures, technologies, and drugs. The aim was to help reduce the burden of injury for wounded Service members, Veterans, and civilians and to increase return-to-duty and return-to-work rates. Relative to its burden of disease, musculoskeletal injuries (MSKIs) are one of the most disproportionately underfunded conditions. The focus of the PRORP includes a broad spectrum of MSKI in areas related to unique aspect of combat- and some noncombat-related injuries. The PRORP may serve as an important avenue of research for nonmilitary communities by offering areas of shared interests for the advancement of military and civilian patient cohort MSKI care. The purpose of this study was to provide a descriptive analysis of the DoD PRORP, which is an underrecognized but high value source of research funding for a broad spectrum of both combat- and noncombat-related MSKIs.

METHODS

The complete PRORP Funding Portfolio for FY2009-FY2017 was obtained from the Congressionally Directed Medical Research Programs (CDMRP), which includes 255 awarded grants. Information pulled from the CDMRP included awardee descriptors (sex, education level, affiliated institution type, research specialty, and previous award winner [yes/no]) and grant award descriptors (grant amount, year, primary and secondary awarded topics, research type awarded, and mechanism of award). Distribution statistics were broken down by principal investigator specialty, sex, degree, organization type, research type, mechanism, and research topics. Distribution and statistical analysis was applied using R software version 3.6.3.

RESULTS

From FY2009 to 2017, $285 million was allocated for 255 PRORP-funded research studies. The seven major orthopaedic subspecialties (foot and ankle, hand, musculoskeletal oncology, pediatrics, spine, sports medicine, and trauma) were represented. Trauma and hand subspecialists received the largest amount of funding, approximately $28 (9.6%) and $22 million (7.1%), respectively. However, only 22 (8.6%) and 26 (10.2%) of the primary investigators were trauma and hand subspecialists, respectively. The primary research categories were diverse with the top five funded PRORP topics being rehabilitation ($53 million), consortia ($39 million), surgery ($37 million), device development ($30 million), and pharmacology ($10 million).

DISCUSSION

The CDMRP funding represents an excellent resource for orthopaedic medical research support that includes trauma and nontrauma orthopaedic conditions. This study serves to promote and communicate the missions of the PRORP both within and beyond the DoD to raise awareness and expand access of available funding for orthopaedic focused research.

SIGNIFICANCE/CLINICAL RELEVANCE

A likelihood exists that this project will provide sustained and powerful influence on future research by promoting awareness of orthopaedic funding sources.

LEVEL OF EVIDENCE

Level III.

Predictors of Temporary Profile Days Among U.S. Army Active Duty Soldiers

Introduction

More than 40,000 soldiers cannot deploy every year, which undermines readiness. The medical readiness of soldiers is a critical component of the overall operational readiness of the U.S. Army. Acute musculoskeletal injuries (MSIs) are the greatest threat to medical readiness. Medical providers place soldiers on temporary profiles to facilitate treatment and recovery of acute MSIs. Poorly managed temporary profiles negatively impact a soldier’s work attendance, resulting in the loss or limitation of over 25 million workdays annually. Upgrading the electronic profile system and implementing the Army Medical Home has led to improvements in managing temporary profiles over the last decade. The Army Medical Home encompasses care delivery platforms, including the Patient-Centered Medical Home (PCMH) and Soldier-Centered Medical Home (SCMH). The structure of U.S. Army PCMHs and SCMHs differ in ways that may affect care processes and patient outcomes. Temporary profile management is an important soldier health outcome that has not been studied in relation to the U.S. Army’s PCMH and SCMH structures or care processes. Access to care, continuity, and communication are three care processes that have been described as essential factors in reducing lost workdays and functional limitations in workers after an acute injury. Understanding the impact of the medical home on temporary profile days is vital to medical readiness. This study aimed to (1) compare temporary profile days between the U.S. Army PCMHs and SCMHs and (2) determine the influence of medical home structures and care processes on temporary profile days among active duty U.S. Army soldiers receiving care for MSIs.

Materials and Methods

This was a retrospective, cross-sectional, and correlational study guided by Donabedian’s conceptual framework. We used secondary data from the Military Data Repository collected in 2018. The sample included 27,214 temporary profile records of active duty U.S. Army soldiers and 266 U.S. Army PCMH and SCMH teams. We evaluated bivariate and multivariate associations between outcomes and predictors using general and generalized linear mixed regression models. The U.S. Army Medical Department Center and School Institutional Review Board approved this study.

Results

Total temporary profile days ranged from 1 to 357, with a mean of 37 days (95% CI [36.2, 37.0]). There was a significant difference in mean temporary profile days between PCMHs (43) and SCMHs (35) (P &lt; 0.001). Soldiers in PCMHs were more likely to have temporary profiles over 90 days (OR = 1.54, 95% CI [1.17, 2.03]). Soldiers in the heavy physical demand category had fewer temporary profile days (P &lt; 0.001) than those in the moderate physical demand category. Age, sex, rank level, physical demand category, profile severity, medical home type, the “explain things” communication subscale, and primary care manager continuity were significant predictors of temporary profile days.

Conclusions

Excessive temporary profile days threaten medical readiness and overall soldier health. Aspects of the medical home structure and care processes were predictors of temporary profile days for musculoskeletal conditions. This work supports continued efforts to improve MSI-related outcomes among soldiers. Knowledge gained from this study can guide future research questions and help the U.S. Army better meet soldier needs.

Musculoskeletal Injuries Among Females in the Military: A Scoping Review

INTRODUCTION

Musculoskeletal injuries (MSKi) are a common challenge for those in military careers. Compared to their male peers, reports indicate that female military members and recruits are at greater risk of suffering MSKi during training and deployment. The objectives of this study were to identify the types and causes of MSKi among female military personnel and to explore the various risk factors associated with MSKi.

MATERIALS AND METHODS

A scoping review was conducted over a 4-month time frame of English language, peer-reviewed studies published from 1946 to 2019. Search strategies for major biomedical databases (e.g., MEDLINE; Embase Classic + Embase; and the following EBM Reviews-Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment, and the NHS Economic Evaluation Database) were developed by a senior medical information specialist and included 2,891 titles/abstracts. Study selection and data collection were designed according to the Population, Concept, and Context framework. Studies were included if the study population provided stratified data for females in a military context.

RESULTS

From a total of 2,287 citations captured from the literature searches, 168 peer-reviewed publications (144 unique studies) were eligible for inclusion. Studies were identified from across 10 countries and published between 1977 and 2019. Study designs were primarily prospective and retrospective cohorts. Most studies assessed both prevalence/incidence and risk factors for MSKi (62.50%), with few studies assessing cause (13.69%). For MSKi of female recruits compared to active female members, the prevalence was higher (19.7%-58.3% vs. 5.5%-56.6%), but the incidence (0.02%-57.7% vs. 13.5%-71.9%) was lower. The incidence of stress fractures was found to be much higher in female recruits than in active members (1.6%-23.9% vs. 2.7%). For anthropometric risk factors, increased body fat was a predictor of MSKi, but not stress fractures. For physiological risk factors for both female military groups, being less physically fit, later menarche, and having no/irregular menses were predictors of MSKi and stress fractures. For biomechanical risk factors, among female recruits, longer tibial length and femoral neck diameter increased the risk of stress fractures, and low foot arch increased risk of an ankle sprain. For female active military members, differences in shoulder rotation and bone strength were associated with risk of MSKi. For biological sex, being female compared to male was associated with an increased risk of MSKi, stress fractures, and general injuries. The consequences of experiencing MSKi for active military included limited duties, time off, and discharge. For recruits, these included missed training days, limited duty days, and release.

CONCLUSIONS

This scoping review provides insight into the current state of the evidence regarding the types and causes of MSKi, as well as the factors that influence MSKi among females in the military. Future research endeavors should focus on randomized controlled trials examining training paradigms to see if women are more susceptible. The data presented in the scoping review could potentially be used to develop training strategies to mitigate some of the identified barriers that negatively impact women from pursuing careers in the military.