Cardiovascular Demand Differences Between Male and Female US Marine Recruits During Progressive Loaded Hikes.

ABSTRACT: Schram, B, Orr, R, Niederberger, B, Givens, A, Bernards, J, and Kelly, KR. Cardiovascular demand differences between male and female US Marine recruits during progressive loaded hikes. J Strength Cond Res XX(X): 000-000, 2024-Despite having to carry the same occupational load, female soldiers tend to be lighter than male soldiers. The aim of this study was to determine the differences in cardiovascular load between female and male US Marine recruits during progressive load carriage hikes. United States Marine Corps recruits (565 male recruits; 364 female recruits) completed 6 loaded hikes over 6 weeks (1: 10 kg, 30 minutes; 2: 10 kg, 45 minutes; 3: 15 kg, 30 minutes, 4: 15 kg, 45 minutes; 5: 20 kg, 30 minutes; 6: 20 kg, 45 minutes) during which cardiovascular response was measured. Average heart rate (HRavg), HR maximum (HRmax), and pace were measured via a wrist-worn physiological monitor. Independent sample t-tests were conducted to compare between sexes, with significance set at 0.008 after adjusting for multiple comparisons. The average female recruit had significantly lower body mass (BM) compared with the average male recruit (p < 0.001) and thus carried a significantly heavier relative load. (10 kg ∼17%, 15 kg ∼25%, 20 kg ∼33%, p < 0.001). There were no significant differences in pace in any hike, and no significant differences were found in HRavg or HRmax when comparing female and male Marines during Hike 1. For female Marines, HRavg was significantly higher compared with male Marines during Hike 2 (+6.5 b·min-1, p < 0.001) and Hike 3 (+7.4 b·min-1, p < 0.001), and both HRavg and HRmax were significantly higher in Hike 4 (+11.9 b·min-1, +8.4 b·min-1, p < 0.001), Hike 5 (+7.7 b·min-1, +7.9 b·min-1, p < 0.001), and Hike 6 (+6.9 b·min-1, +7.1 b·min-1, p < 0.001), respectively. Female Marines endured greater cardiovascular demand compared with male Marines during load carriage events when carrying loads greater than 15 kg (∼25% BM).

Exploring the Impact of Firefighter Trainee Fitness on Academy Graduation or Release.

ABSTRACT: Lockie, RG, Orr, RM, Montes, F, and Dawes, JJ. A research note exploring the impact of firefighter trainee fitness on academy graduation or release. J Strength Cond Res 38(5): 999-1003, 2024-This study investigated the impact of fitness test performance on firefighter trainee ability to graduate an academy using ordinal logistic generalized linear models. Retrospective analysis was conducted on trainee data ( N = 686) from one fire department who completed an occupational physical ability test (OPAT) that included the following: Illinois agility test (IAT); push-ups; pull-ups; leg tucks; maximal aerobic capacity (V̇ o2 max); backward overhead 4.54-kg medicine ball throw (BOMBT); 10-repetition maximum deadlift; and 91.44-m farmer's carry. Data were recorded in raw and scaled scores based on internal scoring (tests scored from 0 to 100; maximum total OPAT score of 800). Trainees were split into graduated ( n = 576) or released ( n = 110) groups. Data were analyzed through ordinal logistic generalized linear models ( p < 0.05). Raw and scaled scores were investigated separately, with odds ratios (OR) and confidence intervals (CI) produced. Regarding raw scores, there was a difference in the odds of graduating relative to the IAT (OR = 1.357; CI = 1.047-1.760; p = 0.021), BOMBT (OR = 0.744; CI = 0.628-0.882; p < 0.001), and V̇ o2 max (OR = 0.907; CI = 0.862-0.954; p < 0.001). For scaled scores, there was a difference in the odds of graduating relative to the points attained for the BOMBT (OR = 0.985; CI = 0.972-0.999; p = 0.032), deadlift (OR = 0.982; CI = 0.968-0.995; p = 0.008), and total OPAT (OR = 0.994; CI = 0.988-1.000; p = 0.047). Change-of-direction speed (IAT), total-body power (BOMBT), aerobic fitness (V̇ o2 max), lower-body strength (deadlift), and overall fitness (total OPAT points) impacted the odds of trainee fire academy graduation. The IAT presented as the largest impacting variable where, for every unit increase in time (i.e., a slower IAT), there was 1.36 greater chance of a trainee being released from the academy.

Determining the Changes in Law Enforcement Recruit Aerobic Fitness Using the 2.4-km Run and 20-m Multistage Fitness Test. Does the Type of Test Matter?

ABSTRACT: Campbell, P, Maupin, D, Lockie, RG, Dawes, JJ, Simas, V, Canetti, E, Schram, B, and Orr, R. Determining the changes in law enforcement recruit aerobic fitness using the 2.4-km run and 20-m multistage fitness test. Does the type of test matter? J Strength Cond Res XX(X): 000-000, 2023-Aerobic fitness is linked with academy graduation, employment, and the long-term health of law enforcement officers and is often used as a training outcome. However, different tests can be used, and aerobic improvements may differ according to the test used. The aim of this study was to determine whether recruits improved to a greater extent in 1 aerobic test compared with the other. Retrospective data from 5 law enforcement recruit cohorts (males = 741; females = 353) who underwent 18 weeks of academy training were analyzed. Initial 20-m multistage fitness test (20MSFT) and 2.4-km run assessments were completed during weeks 4 and 5 of training, with final testing completed during weeks 16 and 17, respectively. A repeated-measures analysis of variance (p < 0.05) with a Bonferroni post hoc analysis determined changes in aerobic fitness in the 20MSFT and 2.4-km run between male and female recruits. A mean difference of 9.27 (95% confidence intervals [CI] 14.8-10.9; d = 0.63; p < 0.001) shuttle increase in 20MSFT performance and 20.1 (95% CI 16.0-24.2; d = 0.49; p < 0.001) second improvement in 2.4-km run time were demonstrated when averaged across sex, yielding a larger performance improvement for the 20MSFT compared with the 2.4-km run. Conversely, there was a smaller magnitude of change in aerobic fitness between male recruits and female recruits for the 20MSFT (d = 0.47) compared with the 2.4-km run (d = 0.50). The findings indicate that current academy training results in improvements to aerobic fitness and to a greater magnitude in the 20MSFT compared with the 2.4-km run. These results may affect policy considerations for law enforcement agencies regarding aerobic test selection.

Expanding Research on Firefighter Trainee Fitness, Reasons for Academy Release, and the Predictive Capabilities of Fitness Tests.

ABSTRACT: Lockie, RG, Orr, RM, Montes, F, and Dawes, JJ. Expanding research on firefighter trainee fitness, reasons for academy release, and the predictive capabilities of fitness tests. J Strength Cond Res 38(4): 724-733, 2024-Firefighter trainees need a level of fitness to be admitted to and complete a training academy. Fitness could indicate a trainee's likelihood of graduation, in addition to their reasons for release. This study determined fitness differences between firefighter trainees who graduated (GRAD) from academy or were released because of injury (RELI), performance test failures (RELP), or resignation (RELR), and whether fitness predicted graduation. Occupational physical ability test (OPAT) data for 686 trainees were analyzed, including: Illinois agility test; push-ups; pull-ups; leg tucks; maximal aerobic capacity (V̇O2max); backward overhead medicine ball throw; 10-repetition maximum deadlift; and farmer's carry. Raw and scaled (based on internal scoring) scores were recorded. Trainees were split into GRAD (n = 576), RELI (n = 33), RELP (n = 66), and RELR (n = 11) groups. A 1-way ANOVA with Bonferroni post hoc calculated between-group differences. Stepwise linear regression determined whether fitness predicted group inclusion. Receiver operating curves and area under the curve (AUC) derived test accuracy for predicting academy release. The GRAD group was superior (p ≤ 0.04) to the RELI group in all tests except push-ups, pull-ups, and farmer's carry; RELP group in all tests except the farmer's carry; and RELR group in V̇O2max, deadlift, and total OPAT score. Select fitness tests could predict inclusion in each group, although the explained variances were low (∼1-11%). Raw V̇O2max (AUC = 0.71) and total OPAT score (AUC = 0.74) had acceptable prediction accuracy. Fitness influenced academy graduation and reasons for release. Scaled scores could predict group inclusion in this department; V̇O2max and total OPAT score provided the most accurate predictors for release.

Profiling injuries sustained following implementation of a progressive load carriage program in United States marine corps recruit training.

BACKGROUND: Load carriage tasks during United States Marine Corps (USMC) recruit training can cause injury. Load carriage conditioning, if optimized, can reduce injury risk. OBJECTIVE: To compare injuries sustained by USMC recruits following participation in either the Original Load Carriage (OLC) program or a Modified Load Carriage (MLC) program. METHODS: Retrospective musculoskeletal injury data were drawn from the USMC San Diego Sports Medicine injury database for recruits completing the OLC (n = 2,363) and MLC (n = 681) programs. Data were expressed as descriptive statistics and a population estimate of the OLC:MLC relative risk ratio (RR) was calculated. RESULTS: The proportion of injuries sustained in the MLC cohort (n = 268; 39% : OLC cohort, n = 1,372 : 58%) was lower, as was the RR (0.68, 95% CI 0.61- 0.75). The leading nature of injury for both cohorts was sprains and strains (OLC n = 396, 29%; MLC n = 66; 25%). Stress reactions were proportionally higher in MLC (n = 17, 6%; OLC n = 4, 0.3%), while stress fractures were proportionately lower (MLC n = 9, 3%; OLC n = 114, 8%). Overuse injuries were lower in MLC (- 7%). The knee, lower leg, ankle, and foot were the top four bodily sites of injuries and the Small Unit Leadership Evaluation (SULE), Crucible, overuse-nonspecific, running, and conditioning hikes were within the top five most common events causing injury. The prevalence rates of moderate severity injury were similar (MLC = 23%; OLC = 24%), although MLC presented both a higher proportion and prevalence of severe injuries (MLC = 6%; OLC = 3%, respectively). CONCLUSION: A periodized load carriage program concurrently increased exposure to load carriage hikes while reducing injuries both during the load carriage hikes and overall.

Incidence and Risk Factors for Acute Articular Cartilage Tears in Military and Other Occupational Settings: A Systematic Review.

Damage to the articular cartilage resulting in an acute tear can lead to functional changes within the joint and increase the risk of osteoarthritis developing. There is limited understanding of the association between occupational risk factors and sustaining an acute articular cartilage tear in the military and other physically demanding occupations. Therefore, the aim of this systematic review was to identify and evaluate original research reporting on occupational risk factors associated with sustaining acute articular cartilage tears. METHODS: A systematic review following the Preferred Reporting Items for Systematic review and Meta-Analysis-Protocols was conducted and registered with the Open Science Framework. Key academic databases were searched using terms from the following concepts: risk or cause, paid occupations, and acute articular cartilage tears. RESULTS: Of an initial 941 studies, 2 studies met the eligibility criteria, both reporting data from military contexts; only one evaluated acute articular cartilage tears in both males and females. One paper focused on articular cartilage injury within the knee and the other within the ankle joint with incidence rates being 0.2 and 0.3 per 1000 person-years, respectively. People in more physically active occupations and individuals with an above-normal body mass index were reported as being at higher risk of sustaining an acute articular cartilage tear. CONCLUSION: Physically demanding occupations, such as the military, may increase the risk for acute tears of the articular cartilage. However, the findings of this review indicate there is a paucity of research to underpin understanding of the injury mechanisms and occupational risk factors for acute articular cartilage tears.

A profile of occupational tasks performed by mounted police officers.

BACKGROUND: Within individual policing organisations, there are a wide variety of units and job roles. OBJECTIVE: To profile the occupational tasks performed by Australian mounted police officers, aiming to offer conditioning insight into this unique job role. METHODS: Thirteen fully qualified and operational mounted police officers (n = 11 females), who served in the mounted police unit for ∼3.3 (±2.3) years, participated in this observational cohort study. Participants completed a survey outlining common occupational tasks and were monitored throughout four consecutive shifts. Participants' heart rate (HR), respiratory rate (RR), and skin temperature (ST) data were collected via wearable monitoring (Equivital EQ-02, Hidalgo, UK) and body position, physical activity undertaken, task effort, and load carriage were recorded by researchers. A one-way ANOVA was used to assess mean differences in physiological measures between the three most reported tasks. RESULTS: Survey identified 130 tasks, with 38 listed as most common. The three most reported mounted police tasks were: 'horse riding' (n = 13, 34%), 'mounted patrols' (n = 10, 26%), and 'horse care' (n = 10, 26%). These were also reported as the most physically demanding. HR during 'horse care' and 'horse riding' were significantly higher than when 'mounted patrolling' (27±7bpm, p = 0.001 and 33±8bpm; p = 0.001, respectively). Mean RR was higher when 'horse riding' when compared to 'horse care' (5.3±1.6brpm) and 'mounted patrol' (8.5±1.9brpm). CONCLUSION: Mounted police officers experience unique physiological challenges throughout their routine occupational tasks. This study highlights the significance of understanding occupation-specific tasks and stressors undertaken by mounted police to develop relevant conditioning, rehabilitation, and monitoring procedures.

Occupational stress and musculoskeletal disorders in firefighters: the mediating effect of depression and job burnout.

The firefighting profession carries a heightened risk of musculoskeletal disorders. A firefighter's job is physically demanding and includes activities such as running, climbing, dragging, and lifting. Often, these tasks are unpredictable, performed in harsh environments, and have been found to cause psychological stress. The purpose of this study was to investigate the effects of occupational stress on work-related musculoskeletal disorders (WRMSD) in firefighters. In addition, the mediating effects of depression and job burnout on proposed relationships were examined. Data informing this study were collected using a survey questionnaire. The survey questionnaire included the Beck Depression Inventory, the Center for Epidemiological Studies Depression Scale (CES-D), the Maslach Burnout Inventory, the Post Traumatic Stress Disorder Inventory (PCL), and the Nordic Musculoskeletal Questionnaire. Collected data were analyzed using structural equation modeling approach in AMOS. The results of the 2339 responding firefighters suggest that work related stress is positively related to WRMSDs in firefighters and can lead to musculoskeletal symptoms through four paths, being emotional exhaustion, personal accomplishment, CES-D total score, and depersonalization. Through depersonalization, job stress had the most significant impact on musculoskeletal symptoms (coefficient = 0.053). Furthermore, the results showed that post-traumatic stress disorders (PTSD) can affect musculoskeletal symptoms through ten paths, again through depersonalization, PTSD had the most significant impact on musculoskeletal symptoms (coefficient = 0.141). The results of this study suggest that organizations should design interventions and policies to prevent and manage occupational stress, depression, and job burnout to negate its undesired consequences on firefighters' health (i.e. WRMSD).

Relationships between job stress, post-traumatic stress and musculoskeletal symptoms in firefighters and the role of job burnout and depression mediators: a bayesian network model.

INTRODUCTION: Job stress, post-traumatic stress disorder (PTSD), and negative psychological outcomes in firefighters can be caused, or aggravated, by their work. These mental disorders can impart musculoskeletal symptoms. This study aimed to investigate relationships between musculoskeletal and psychological disorders in a population of firefighters using a Bayesian network model. METHODS: This cross-sectional study, conducted in 2022, included 2339 firefighters who completed questionnaires during their rest periods. The questionnaires comprised of demographical information, the Occupational Stress Questionnaire-HSE, the PTSD Checklist, Maslach Burnout Inventory, Center for Epidemiologic Studies - Depression scale (CES-D), and Nordic Musculoskeletal Questionnaire. GeNIe academic software was used to analyze the Bayesian network. RESULTS: High job stress and high PTSD each increased the probability of musculoskeletal symptoms by 34%. When combined, high job stress and high PTSD increased the probability of musculoskeletal symptoms by 37%. Among the mediator's burnout and depression, depression had the highest association with musculoskeletal symptoms. CONCLUSIONS: Job stress and PTSD can increase musculoskeletal symptoms and are influenced by psychological mediators (like burnout and depression). Adopting preventive and therapeutic measures to mitigate job stress and PTSD, mitigate and rehabilitate WMSD, and manage associated mediators are critical for the mental and physical health of firefighters.

Heart rate variability profile changes associated with specialist police selection activities: A case study.

BACKGROUND: Police Tactical Groups (PTGs) are specialist police units tasked with rigorous physical and psychosocial duties. Consequently, selection courses (SCs) for service in these units must also be rigorous. Given the intensity of SCs, holistic monitoring for potential overstress may be beneficial. Heart Rate Variability (HRV) is one holistic stress measure that can be obtained in austere environments. OBJECTIVE: The purpose of this study was to profile HRV during a PTG SC. Six (n = 6) qualified male police officers attempted a 36-hour PTG selection course held at an Australian state facility. METHODS: HRV was obtained from Equivitaltrademark EQ02 + LifeMonitor bioharnesses. The selection course consisted of physically demanding events with minimal sleep (approx. 45 mins). Only one candidate completed the full selection course; whose results are reported here. RESULTS: A visual time-series of 384 consecutive 5 min HRV analyses was generated. Contextual analysis was applied to appreciate HRV changes between SC serials. HRV decline occurred during the planning of a navigation exercise and a pack march. Increases in HRV were observed throughout the pack march exercise and rest period. CONCLUSION: This case study demonstrates the potential utility for selection personnel to obtain additional insight into candidate responses to various occupational challenges throughout an SC. Information provided by HRV monitoring may support leadership decisions when evaluating personnel holistically. For example, the ability to continue occupational task execution even while experiencing potential overstress (as measured by HRV) and after food and sleep deprivation is desirable. HRV may potentially inform stakeholders regarding overstress in PTG candidates.

Effects of a single-day pre-academy physical test training session on physical fitness scores of police candidates.

BACKGROUND: Concerns are sometimes raised by police applicants undertaking physical fitness testing that they were unfamiliar with the test requirements which in turn negatively impacted their performance. OBJECTIVE: The aim of this study was to investigate the effects of a single day physical test training session on physical fitness scores of police candidates. METHODS: The sample consisted of female police candidates (n = 133) who attended a pre-academy training session. On the first day of pre-training, candidates' physical fitness was measured following official assessment day protocols. Measures included maximal handgrip strength, number of push-ups in 10 sec (PU), number of sit-ups in 30 sec (SU), standing long jump (SLJ), Abalakow jump test (AJ), 12 min Cooper running test (CT), and a motor educability test (ME). After the assessment, the overseeing UCIPS staff provided a detailed test skills briefing to candidates (e.g., common mistakes made during testing, how test performance could be improved, etc.). Immediately after the briefing, candidates performed the tests once again. Differences between results were measured using a paired samples t-test with significance set at 0.05. RESULTS: Paired sample t-tests determined significant (p < 0.001), large (Rank-Biserial Correlation = 1.00), improvements in physical fitness scores during the second assessment following familiarisation and feedback on test performance. CONCLUSION: Pre-academy training may be effective in improving candidates' physical fitness scores, in most tests, prior to the official assessment for the enrolment to police studies. Thus, to optimise initial candidate scores and opportunities for successful enlistment, police agencies may benefit from providing pre-assessment training.

Evaluating the Variability Between 20-m Multistage Fitness Test Estimating Equations in Law Enforcement Recruits.

ABSTRACT: Campbell, P, Maupin, D, Lockie, RG, Dawes, JJ, Simas, V, Canetti, E, Schram, B, and Orr, R. Evaluating the variability between 20-m multistage fitness test estimating equations in law enforcement recruits. J Strength Cond Res 38(4): 742-748, 2024-The 20-m multistage fitness test (20MSFT) is commonly used by law enforcement agencies to measure aerobic fitness and to estimate maximal aerobic consumption (V̇ o2 max). These measures are an important occupational variable with aerobic fitness levels linked to employment status, occupational performance, and long-term health in law enforcement officers. There are a multitude of predictive equations used to provide an estimate of V̇ o2 max, with the extent of variability in the estimated V̇ o2 max currently unknown in this population. This has consequences for comparisons between, and across, differing agencies, and in capabilities of deriving normative data. The aim of this investigation was to compare the variability in estimated V̇ o2 max scores derived from different 20MSFT predictive equations. The 20-m multistage fitness test data from 1,094 law enforcement recruits (male n = 741, 25.2 ± 6.3 years; female: n = 353, 25.6 ± 5.6 years) from a single agency were retrospectively analyzed. The 20MSFT scores were transformed into estimated V̇ o2 max scores using 6 different predictive equations. Significance was set at p < 0.05. Results demonstrated significantly different V̇ o2 max scores between each predictive equation ( p < 0.001; d = 0.25-1.53) and between male and female recruits ( p < 0.001, r = 0.55). All estimated V̇ o2 max equations showed small to very strong correlations with each other ( p < 0.001; r = 0.32-0.99). The findings indicate considerable dispersion of V̇ o2 max scores when using differing equations, suggesting raw 20MSFT variables (e.g., shuttles or distance completed) should be preferred to measure and apply results from aerobic fitness tests if standardized approaches are not developed within law enforcement.

Identifying the most important, frequent, and physically demanding tasks of Brazilian firefighters.

This study aimed to identify the most important, frequently performed, and physically demanding tasks performed by Brazilian firefighters and to identify tasks that could be used to assess physical fitness. A subjective task analysis was conducted. Five hundred twenty-four firefighters (84% male; 16% females) responded to an online survey and rated 37 tasks across three domains (most important, most frequent, and most physically demanding). A dichotomous decision analysis was used to inform the proposed physical fitness tests. Wildland firefighting tasks presented the highest overall mean rate. Traffic control was considered the most important and frequently performed task. Lifeguard rescue was considered the most physically demanding task. The dichotomous analysis identified 14 essential tasks (seven structural firefighting and seven automobile accidents). The tasks identified may be helpful in developing criterion physical fitness tests and training programs related to firefighters' demands.Practitioner summary: The unpredictability, variability, and dangerousness of firefighting make it challenging to observe the physical demands imposed on firefighters. A subjective task analysis was conducted to identify essential tasks performed by Brazilian firefighters. Wildland firefighting, lifeguard rescue, automobile accidents, and structural firefighting tasks were the most important, frequent, and physically demanding.

Relationships Between Anthropometric Measures and Body Composition With Individual ACFT Event Performance Among Army Reserve Officers' Training Corps Cadets.

ABSTRACT: Thompson, MB, Lawson, DJ, Orr, RM, Lockie, RG, and Dawes, JJ. Relationships between anthropometric measures and body composition with individual ACFT event performance among army reserve officers' training corps cadets. J Strength Cond Res 38(4): 749-754, 2024-The U.S. military commonly uses body composition as an indicator of a soldier's potential to meet the physical demands required of their occupation. The purpose of this study was to determine whether significant relationships existed between select body composition variables and Army Combat Fitness Test (ACFT) performance among a cohort of university Army Reserve Officers' Training Corps (ROTC) cadets. Twenty-six male (20.4 ± 1.6 years, 81.8 ± 8.5 kg, 178.3 ± 7.8 cm) and 12 female (19.9 ± 1.4 years, 64.2 ± 6.7 kg, 161.9 ± 4.9 cm) cadets voluntarily participated in this study. Body composition was measured using bioelectrical impedance analysis, and ACFT event scores were recorded by the cadre using the U.S. Army standard protocol and provided to the investigators. Pearson's correlations were used to identify relationships between body composition variables and ACFT event performance with an alpha level of p ≤ 0.05. Moderate to strong relationships were observed between total body water, dry lean mass, lean body mass, skeletal muscle mass, body fat mass (FM), and body fat percentage and all event scores for the sample as a whole. Body mass index showed weak to moderate significant positive relationships with hand-release push-up and maximum hexagonal bar deadlift in the sample as a whole. No relationships were observed in the men of this sample. All body composition variables showed moderate, nonsignificant relationships with at least 1 ACFT event within the women of this sample. Considering the findings of this study, a multitude of variables could be useful to assess ROTC cadets as predictors for ACFT performance. Reserve Officers' Training Corps programs should emphasize attaining and maintaining functional lean mass, whereas reducing nonfunctional body mass (i.e., excess FM) among cadets to enhance health and performance across the occupational life span.

Introduction of an applicant Job-Related Task Assessment (JTA) and the effects on the health and fitness of police recruits.

BACKGROUND: In 2020, a police department in the south-eastern USA introduced a Job-Related Task Assessment (JTA). The JTA included running, climbing, crawling, balance, direction changes, stair climbing, dragging, pushing, and simulated controlling of a struggling subject and needed to be completed by applicants in 6 : 57 min:s. It is not known whether introducing the JTA in the hiring process affected the health and fitness of hired recruits. OBJECTIVE: To compare the health and fitness of recruits hired prior to, and following, the JTA introduction. METHODS: Analysis was conducted on recruit data split into academy training year: 2016 (n = 91), 2017 (n = 129), 2018 (n = 167), 2019 (n = 242), and 2020 (n = 37). The 2020 group was hired after the JTA introduction and included one academy class. The following were recorded for all recruits: age, height, body mass, and body mass index; systolic and diastolic blood pressure (BP); sit-and-reach; grip strength; push-ups; sit-ups; 2.4-km run; and a physical ability test (PAT). A univariate ANOVA, with sex and age as covariates and Bonferroni post hoc, determined between-year differences. RESULTS: The recruits from 2020 were significantly lighter than 2018 recruits (p < 0.031), had higher systolic and diastolic BP than recruits from 2016-2018 (p≤0.006), completed the 2.4-km run faster than recruits from all years (p < 0.001), and completed the PAT faster than the 2016 and 2019 (p = 0.006-0.007) recruits. CONCLUSION: The JTA introduction led to the selection of recruits with lower body mass, and better aerobic (2.4-km run) and job-specific fitness (PAT). However, 2020 recruits also had higher BP which should be monitored.

Physical fitness test performance in firefighter trainees: Differences between graduated and released trainees and predicting academy graduation.

BACKGROUND: Fitness tests have been previously used to predict academy graduation and highlight specific capacities to be targeted in applicants/trainees to optimise their potential for academy success. OBJECTIVE: To compare the fitness of graduated and released (did not complete academy requirements) firefighter trainees and explore using decision tree analysis to predict academy graduation via fitness tests. METHODS: Retrospective analysis was conducted on 686 trainees who completed an occupational physical ability test (OPAT): Illinois agility test; push-ups; pull-ups; leg tucks; estimated maximal aerobic capacity (VO2max); backwards overhead 4.54-kg medicine ball throw; 10-repetition maximum deadlift; and 91.44-m farmer's carry. Data were recorded in raw and scaled scores (tests scored from 0-100; maximum OPAT score was 800). Trainees were split into 'graduated' (GRAD; n = 576) or 'released' (REL; n = 110) groups. Mann-Whitney U-tests compared between-group OPAT scores. A decision tree analysis using Chi-square automatic interaction detection was conducted, with raw and scaled scores entered into the analysis. A separate analysis was conducted with only the raw scores. RESULTS: GRAD trainees outperformed REL trainees in all OPAT events (p < 0.001). OPAT total score was the best predictor of academy graduation (p < 0.001), followed by the deadlift score (p = 0.003). Estimated VO2max was the only significant raw score predictor (p < 0.001). CONCLUSIONS: GRAD trainees were fitter than the REL trainees. Fitness could predict trainees who graduated from the academy. Overall fitness (OPAT total score), muscular strength (deadlift) and aerobic capacity were important graduation predictors. Training staff could develop these fitness qualities in their trainees to potentially improve fire academy graduation rates.

The global prevalence of musculoskeletal disorders among firefighters: a systematic review and meta-analysis.

This systematic review and meta-analysis study aimed to explore the global prevalence of musculoskeletal disorders (MSDs) among firefighters. A systematical search was performed in three international academic databases (Scopus, PubMed and Web of Science). Overall, 31 articles were included in this review. The pooled prevalence of total MSDs in firefighters was identified as 41% (95% confidence interval [CI] [33, 50]). The prevalence of MSDs in neck, shoulders, upper back, lower back, upper extremity and lower extremity was 9% (95% CI [7, 10]), 11% (95% CI [8, 15]), 8% (95% CI [5, 12]), 31% (95% CI [27, 34]), 13% (95% CI [9, 17]) and 16% (95% CI [14, 18]), respectively. No statistically significant relationship was observed between prevalence of MSDs and year of study, mean age, size of sample, duration of prevalence, region or income level. Demographic, occupational and medical condition factors were identified that can create these disorders among firefighters.

Occupation-Induced Fatigue and Impacts on Emergency First Responders: A Systematic Review.

Fatigue in emergency first responders (EFRs) is known to affect performance abilities and safety outcomes for both patients and EFRs. The primary aim of this review was to determine the main contributors to occupation-induced fatigue in EFRs and its subsequent impacts. Following the PRIMSA checklist, academic databases (Medline, Embase, CINAHL, and SPORTDiscus) were searched using key terms with results subjected to inclusion and exclusion criteria. Populations of interest were firefighters, paramedics, or emergency call centre personnel. Of the 5633 records identified, 43 studies, which reported on 186 unique measures from a total population of 6373 participants, informed the review. Synthesis revealed fatigue was caused by lack of sleep during the shift and consistent poor sleep quality which negatively impacted cognitive function, alertness, and physical and mental health while increasing safety-compromising behaviours and injuries. Both subjective and objective assessments of fatigue are necessary for effective risk management in EFRs. EFRs that are consistently fatigued are at a greater risk of poor physical and mental health, reduced cognitive function, and increased injuries. No studies reported on fatigue in emergency call centre personnel, highlighting a literature gap. Funding was provided by the Australian Capital Territory Emergency Services Agency. Preregistration was filed in OSF: osf.io/26f3s.

Heart Rate Variability Assessment of Land Navigation and Load Carriage Activities in Specialist Police Selection.

Police tactical group (PTG) personnel are exposed to physical, mental, and emotional stressors. Consequently, PTG selection courses (SCs) impart similar challenges, often resulting in candidate attrition. Holistic assessment may provide additional support to stakeholders given these risks. Heart Rate Variability (HRV) is an objective holistic stress measure that may be applicable in PTG SCs but has not been thoroughly researched. Therefore, this study aimed to report HRV data in an end-user accessible format and determine the relationship between HRV and attrition. A total of 18 qualified Australian State law enforcement officers completed a 1-day physical readiness assessment. Of those, six males progressed to an additional two-day course, on which this study is focused. This two-day selection consisted of additional physical challenges and occupational assessments. HRV was obtained from 2-lead ECGs and defined as the percentage of R-R intervals that varied by ≥50 ms (pRR50). Data were summarized in a heat map of consecutive short-term analyses. Three candidates withdrew. A logistic regression based on heat map data found high HRV was significant for predicting attrition, χ2 (6) = 8.318, p = 0.004. HRV may provide insight for PTG stakeholders monitoring attrition. While the sample size was limited and replication is needed, this study tentatively establishes value for HRV monitoring in PTG SCs.