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.

Relationship Between Metabolic Fitness and Performance in Police Occupational Tasks

Purpose To determine the relationship between metabolic fitness test scores and performance in police occupational tasks.Methods Retrospective data from 106 law enforcement officers who completed two metabolic fitness assessments[anaerobic:a 20-m (10-m and 20-m splits) sprint,aerobic:20 m Multi-Stage Fitness Test (20 m-MSFT)]and three routine occupational tasks[1.22 m Fence jump (FJ),8.5 m Victim Drag (VD with 102.3 kg) and "Get-up" (GU)]were collected.A Person's cor-relation coefficient and a standard multiple regression were used to assess the relationship between and predictive ability of,respectively,the fitness tests scores and performance on occupational tasks.Results There was a significant positive correlation between the 10-m sprint scores and FJ (r=0.524,P<0.001),VD(r =0.528,P < 0.001) and GU (r=0.486,P < 0.001).Similarly,the 20-m sprint scores were significantly and moderately correlated with FJ (r=0.573,P < 0.001),VD (r=0.603,P < 0.001) and GU (r=0.533,P < 0.001).These anaerobic tests' scores predicted approximately 40% of the performance in the occupational tasks analysed.The MSFT fitness assessment had a small,albeit significant negative correlation with the three tasks:FJ (r=-0.360,P< 0.001),VD (r=-0.266,P=0.012)and GU (r=-0.375,P< 0.001).Conclusion High levels of metabolic fitness correlated with faster performance in police officer occupational tasks,particu-larly ones of an anaerobic nature (i.e.the maximal sprint tests).In addition to typical aerobic fitness conditioning,anaerobic fitness conditioning could be vital for optimal performance in physically demanding tasks required of police officer.

Associations Between Two Measures of Trunk Muscular Endurance Among Male Law Enforcement Officers

Purpose The purpose of this study was to explore the relationship between two measures of trunk muscular endurance.Methods Retrospective data for 520 male law enforcement officers(age 40.16±7.71 years;height=1.81±0.07 m;body mass=94.4±15.01 kg)belonging to a single US based law enforcement agency were used for this analysis.The data provided included:age,height,body mass,sit-up repetitions completed in 1-min(SU)and time to completion for the isometric prone plank(IPP).A Pearson’s product correlation coefficient was used to determine the relationships between the SU and IPP.Results Significant(P<0.001)moderate(r=0.594,R^(2)=0.352)relationships were discovered between the SU and IPP.Conclusion Based on the results of this study it appears that both the SU and IPP tests are appropriate for evaluating trunk muscular endurance,but measure separate qualities(i.e.,dynamic and static muscular endurance).

Correction to:Associations Between Two Measures of Trunk Muscular Endurance Among Male Law Enforcement Officers

The original version of this article,published on August 7,2020,contained a mistake.The affiliations were incorrect.The correct affiliations of the authors are given below.