Models to predict injury, physical fitness failure and attrition in recruit training: a retrospective cohort study

Background:Attrition rate in new army recruits is higher than in incumbent troops.In the current study,we identified the risk factors for attrition due to injuries and physical fitness failure in recruit training.A variety of predictive models were attempted.Methods:This retrospective cohort included 19,769 Army soldiers of the Australian Defence Force receiving recruit training during a period from 2006 to 2011.Among them,7692 reserve soldiers received a 28-day training course,and the remaining 12,077 full-time soldiers received an 80-day training course.Retrieved data included anthropometric measures,course-specific variables,injury,and physical fitness failure.Multivariate regression was used to develop a variety of models to predict the rate of attrition due to injuries and physical fitness failure.The area under the receiver operating characteristic curve was used to compare the performance of the models.Results:In the overall analysis that included both the 28-day and 80-day courses,the incidence of injury of any type was 27.8%.The 80-day course had a higher rate of injury if calculated per course(34.3%vs.17.6%in the 28-day course),but lower number of injuries per person-year(1.56 vs.2.29).Fitness test failure rate was significantly higher in the 28-day course(30.0%vs.12.1%).The overall attrition rate was 5.2%and 5.0%in the 28-day and 80-day courses,respectively.Stress fracture was common in the 80-day course(n=44)and rare in the 28-day course(n=1).The areas under the receiver operating characteristic curves for the course-specific predictive models were relatively low(ranging from 0.51 to 0.69),consistent with"failed"to"poor"predictive accuracy.The course-combined models performed somewhat better than the course-specific models,with two models having AUC of 0.70 and 0.78,which are considered"fair"predictive accuracy.Conclusion:Attrition rate was similar between 28-day and 80-day courses.In comparison to the 80-day full course,the 28-day course had a lower rate of injury but a higher number of injuries per person-year and of fitness test failure.These findings suggest fitness level at the commencement of training is a critically important factor to consider when designing the course curriculum,particularly short courses.

Depression in military medicine cadets: a cross-sectional study

Background: Military medicine cadets undergo strenuous military training alongside demanding medical studies. This stressful and complex educational environment can lead to the emergence of depressive symptoms. We investigated the prevalence of depressive symptoms in a cohort of military medicine cadets.Methods: We conducted a descriptive questionnaire-based cross-sectional study among Greek military medicine cadets in the undergraduate program of the Hellenic Military School of Combat Support Officers. The Greek translation of the Zung self-rating depression scale questionnaire was used to screen for the presence of depressive symptoms. In addition, demographic, academic and dietary information was collected. The Shapiro-Wilk test of normality, Pearson correlation test, Chi-square test, t-test and Mann Whitney U test were employed for statistical analysis.Results: We enrolled 55 female and 91 male military medicine cadets with a mean age of 19.84 years(SD=0.99). The mean Zung crude score was 43.32(SD=4.55): 42.8(SD=4.43) for female cadets and 43.64(SD=4.6) for male cadets. Cadets were further subdivided into low and high risk groups for the presence of depressive symptoms. We identified 57(39%) cadets with a total Zung crude score of 45 or above: 21 females and 36 males. Statistical analysis did not reveal any significant differences between the two groups based on gender, year of training, academic performance, alcohol consumption, smoking status, vitamin supplementation, dietary habits or BMI.Conclusion: We report a high prevalence of depressive symptoms in a cohort of military medicine cadets that underscores the need for effective screening and appropriate and timely interventions. We did not identify any related risk factors. Military medicine cadets are exposed to a challenging military and medical training environment, and thus represent a group at risk for development of depression.

Military training-related abdominal injuries and diseases:Common types,prevention and treatment

Military training is intense,difficult and often dangerous,so all kinds of injuries or diseases frequently occur during training.Most of the previous studies and reviews on military training-related injuries focused on musculoskeletal system,whereas there are no reviews of abdominal injuries and diseases.Although the incidence of military training-related abdominal injuries and diseases is relatively low,the patients’condition is often critical especially in the presence of abdominal organ injury,leading to multiorgan dysfunction syndrome and even death.This paper elaborates on common types of military training-related abdominal injuries and diseases as well as the prevention and treatment measures,which provides some basis for scientific and reasonable training and improvement of medical security.

An Improved Underwater Confrontation Simulation Method of Naval Amphibious Operational Training System

This paper described an improved underwater confrontation simulation method of naval amphibious operational training system. The initial position of submarine forces on the enemy is generated automatically, and the attacking distance model of torpedoes is established based on the kinematics theory, which is more flexible and reasonable to judge the launch condition compared to traditional method. The two kinds of confrontation behavior models on the enemy submarine are created to depict its tactical action from the defensive to the offensive as well as the contrary, ensuring that operational style is simulated more comprehensively and properly. The existing motion trajectory estimation and collision detection algorithms on operational platforms are also improved to reduce the iteration error and further enhance the detection accuracy of target hit.

Study on the Correlation Between Fracture and Bone Mineral Density Caused by Military Training and the Construction of Prediction Model

Objective:Analyze the correlation between the bone mineral density value of army officers and soldiers and the fracture caused by military training,and construct the prediction model of the risk factors of the fracture caused by military training.Methods:A total of 1019 officers and soldiers in a military training unit from January 2015 to November 2020 were selected and divided into groups according to whether they were fractured during military training.The basic data were collected in the form of a questionnaire,and the bone mineral density of the forearm and wrist of all subjects were measured by osteosys exa-3000 dual-energy X-ray absorptiometry in Korea.Pearson correlation analysis was used to analyze the correlation between bone mineral density and fractures caused by military training.Multivariate logistic regression was used to analyze the risk factors of fractures caused by military training,build a prediction model,and draw an ROC curve to verify its predictive value for fractures caused by military training.Results:There were statistically significant differences between patients with fractures caused by military training and those without fractures in previous fracture history,training period,self-evaluation of training intensity,the intensity of self-protection awareness,and bone mineral density(p<0.05);Multivariate logistic regression analysis showed that past fracture history,training intensity,injury subjects,self-protection awareness,and bone mineral density were all independent factors influencing fractures caused by military training(P<0.05);Pearson correlation analysis showed that bone mineral density was negatively correlated with fractures caused by military training(r=0.686,P<0.01);a predictive model was constructed,model1 was previous fracture history+training intensity+injury subjects+self-protection awareness,model 2 is the previous fracture history+training intensity+injury subjects+self-protection awareness+bone mineral density value.The area under the ROC curve of model 1 and model 2 were 0.729(0.648-0.785)and 0.893(0.837-0.914),respectively,and the Youde index were 0.415 and 0.682,respectively.Conclusion:There is a negative correlation between bone mineral density and fractures caused by military training.The prediction value of the fracture prediction model caused by military training constructed by the bone mineral density value is higher.

Informing management of rare species with an approach combining scenario modeling and spatially explicit risk assessment

Wildlife managers are tasked with identifying and managing stressors that threaten persistence of populations.We demonstrate an approach to land-use planning that combines scenario modeling and ecological risk assessment to map and quantify risk to population persistence for three rare prairie species in Washington State,USA.Following corroboration of model output,we found that of the management scenarios considered,only a scenario with year-round restrictions on use of off-road vehicles,digging,and camping enforced in all potential habitat reduces risk to the species.Decreased risk is focused primarily in two patches of prairie habitat in our study area,indicating stringent restrictions need not be applied broadly.However,one area is not easily accessed by two of the three species considered,suggesting reintroductions to suitable but inaccessible habitat may play an important role in management of these species.Our analyses suggest changes in land use and management that might improve habitat for rare species,with options for minimizing monetary and social costs.Because the proposed approach relies on hypothetical management scenarios and uses a model flexible in data requirements to provide spatially explicit output,it can be used to inform adaptive management of rare species in diverse land-planning processes and will be especially useful when management decisions must be made under time or cost constraints.

Effects of disturbance on small mammal community structure in the New Jersey Pinelands, USA

We compared small mammal community composition among undisturbed habitats and habitats disturbed by military operations on Warren Grove Gunnery Range(WGR)in the New Jersey Pinelands.WGR is one of the largest tracts of protected land within this globally rare ecosystem.Disturbance in the form of fire,mowing,soil disruption and logging has had a large effect on small mammal occurrence and distribution.Of the 14 small mammal species that occur in the Pinelands,9 live on WGR,including large populations of the southern bog lemming(Synaptomys cooperi Baird,1858)and meadow jumping mouse[Zapus hudsonius(Zimmermann,1780)].Simpson’s Index of Diversity was 0 for most disturbed sites and was generally greater in wetlands than in uplands.White-footed mouse[Peromyscus leucopus(Rafinesque,1818)]was the most common species on WGR and had a dominant effect on species diversity and community similarity indices.It dominated upland habitats and was the only species to occur in several disturbed habitats,whereas all 9 species occurred in wetlands.Principal components analysis indicated that most variation in species diversity was explained by disturbance and differences between upland and wetland habitats,due to presence of white-footed mice in disturbed and upland sites.Meadow jumping mice,southern bog lemmings and red-back voles[Myodes gapperi(Vigors,1830)]were positively correlated with wetland habitats,and pine voles[Microtus pinetorum(Le Conte,1830)],short-tail shrews[Blarina brevicauda(Say,1823)]and eastern chipmunks[Tamias striatus(Linnaeus,1758)]were associated with uplands.Habitat heterogeneity at WGR,including extensive undisturbed wetlands and uplands supported a rich diversity of small mammal species.