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.

Can you tell people's cognitive ability level from their response patterns in questionnaires?

Questionnaires are ever present in survey research. In this study, we examined whether an indirect indicator of general cognitive ability could be developed based on response patterns in questionnaires. We drew on two established phenomena characterizing connections between cognitive ability and people's performance on basic cognitive tasks, and examined whether they apply to questionnaires responses. (1) The worst performance rule (WPR) states that people's worst performance on multiple sequential tasks is more indicative of their cognitive ability than their average or best performance. (2) The task complexity hypothesis (TCH) suggests that relationships between cognitive ability and performance increase with task complexity. We conceptualized items of a questionnaire as a series of cognitively demanding tasks. A graded response model was used to estimate respondents' performance for each item based on the difference between the observed and model-predicted response ("response error" scores). Analyzing data from 102 items (21 questionnaires) collected from a large-scale nationally representative sample of people aged 50+ years, we found robust associations of cognitive ability with a person's largest but not with their smallest response error scores (supporting the WPR), and stronger associations of cognitive ability with response errors for more complex than for less complex questions (supporting the TCH). Results replicated across two independent samples and six assessment waves. A latent variable of response errors estimated for the most complex items correlated .50 with a latent cognitive ability factor, suggesting that response patterns can be utilized to extract a rough indicator of general cognitive ability in survey research.

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.

Factors Influencing Marksmanship in Police Officers: A Narrative Review

Law enforcement officers routinely face unpredictable scenarios that may threaten the public, their colleagues, or themselves. In such situations, officers may be required to use firearms, with shooting accuracy becoming crucial. This literature review aimed to identify, synthesize, and report on research investigating factors that affect marksmanship in law enforcement personnel. A systematic search of seven databases was undertaken following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) approach. From an initial 5396 identified studies, 23 met the eligibility criteria. The key findings from these papers were: (1) physical exertion does not appear to decrease shooting performance, especially at close range (<10 m); (2) tactical load carriage does not appear to decrease shooting performance; in fact, it has been reported by officers as improving performance (likely due to training specificity); (3) the physical capability of officers may be of importance, notably grip strength, which the volume of evidence suggests is positively correlated with marksmanship; (4) anxiety imparted through high-stress scenarios negatively impacts shooting performance, but training under stress may counteract this factor, albeit for a short period. Together, these factors appear to have a trainability component where increased specific and realistic training can improve shooting accuracy, time, and precision, especially in high-stress situations.

Profiling the Typical Training Load of a Law Enforcement Recruit Class

Law enforcement academies, designed to prepare recruits for their prospective career, represent periods of high physical and mental stress, potentially contributing to recruits' injuries. Managing stress via monitoring training loads may mitigate injuries while ensuring adequate preparation. However, it is vital to first understand an academy's typical training load. The aim of this study was to profile the typical training load of law enforcement recruits over the course of 22 weeks. Data were prospectively collected using global positioning system (GPS) units placed on recruits during a portion of the academy training, while a desktop analysis was retrospectively applied to six other classes. A Bland-Altman plot was conducted to assess the agreement between the two methods. A linear mixed model was conducted to analyse the difference in distances covered per week, while other variables were presented graphically. Adequate agreement between the desktop analysis and GPS units was observed. Significant differences (p-value < 0.01) in distance covered (9.64 to 11.65 km) exist between weeks during early academy stages, which coincide with increases (~6 h) in physical training. Significant decreases in distances were experienced during the last five weeks of academy training. Most acute:chronic workload ratios stayed between the proposed 0.8 to 1.3 optimal range. Results from this study indicate that large increases in training occur early in the academy, potentially influencing injuries. Utilizing a desktop analysis is a pragmatic and reliable approach for instructors to measure load.

The Impact of Footwear on Occupational Task Performance and Musculoskeletal Injury Risk: A Scoping Review to Inform Tactical Footwear

The aim of this scoping review was to investigate the impact of footwear on worker physical task performance and injury risk. The review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews protocol and registered in the Open Science Framework. Key search terms were entered into five academic databases. Following a dedicated screening process and critical appraisal, data from the final articles informing this review were extracted, tabulated, and synthesised. Of 19,614 identified articles, 50 articles informed this review. Representing 16 countries, the most common populations investigated were military and firefighter populations, but a wide range of general occupations (e.g., shipping, mining, hairdressing, and healthcare workers) were represented. Footwear types included work safety boots/shoes (e.g., industrial, gumboots, steel capped, etc.), military and firefighter boots, sports shoes (trainers, tennis, basketball, etc.) and various other types (e.g., sandals, etc.). Occupational footwear was found to impact gait and angular velocities, joint ranges of motion, posture and balance, physiological measures (like aerobic capacity, heart rates, temperatures, etc.), muscle activity, and selected occupational tasks. Occupational footwear associated with injuries included boots, conventional running shoes, shoes with inserts, harder/stiffer outsoles or thin soles, and shoes with low comfort scores-although the findings were mixed. Occupational footwear was also linked to potentially causing injuries directly (e.g., musculoskeletal injuries) as well as leading to mechanisms associated with causing injuries (like tripping and slipping).

Profiling the absolute and relative strength of a special operations police unit

Background

Specialist police perform high-risk tasks and are required to have, and maintain, a high level of fitness. The aims of this study were to profile the strength of a specialist police unit and to investigate whether this profile remained constant over an 18-month period.

Methods

Retrospective data for 47 special operations police officers (mean initial weight = 88.84 ± 8.25 kg) were provided. Officers were tested five times over 18 months for 1 repetition maximum: bench press, squat, deadlift, and pull-up. All officers continued to participate in their typical physical conditioning programs. Repeated-measures ANOVAs with Bonferroni post-hoc adjustments or Friedman tests with Wilcoxon signed-rank tests were used to compare strength values across all five time points (TPs). Alpha levels were set at 0.05.

Results

All strength values increased significantly over the 18-month period. Over the five TPs, absolute squat increased the most (+ 9%: initial mean = 125.79 ± 24.53 kg), followed by absolute bench press (+ 8%: initial mean = 109.67 ± 19.80 kg), absolute deadlift (+ 7%: initial mean = 151.64 ± 26.31 kg) and absolute pull-up (+ 4%: initial mean = 121.43 ± 14.91 kg). Relatively, the highest increase was found with the squat (+ 8%: initial mean = 1.42 ± 0.25%), followed by the bench press (+ 7%: initial mean = 1.24 ± 0.20%), deadlift (+ 6%: initial mean = 1.71 ± 0.25%) then pull-up (+ 4%: initial mean = 1.37 ± 0.15%). The period between TP3 and TP4 yielded the fewest significant increases compared with other TP differences with only absolute bench press (+ 1.7%), absolute squat (+ 1.1%) and relative bench press (+ 1.6%) changing significantly (p < 0.05).

Conclusions

Specialist police can maintain, even increase strength, while serving in specialist units if provided with a Strength and Conditioning coach and time to train. Given changes over time, constant monitoring is required and a single timepoint may not be optimal to establish normative data.

The Relationship Between Acute: Chronic Workload Ratios and Injury Risk in Sports: A Systematic Review

PURPOSE

Low injury rates have previously been correlated with sporting team success, highlighting the importance of injury prevention programs. Recent methods, such as acute:chronic workload ratios (ACWR) have been developed in an attempt to predict and manage injury risk; however, the relation between these methods and injury risk is unclear. The aim of this systematic review was to identify and synthesize the key findings of studies that have investigated the relationship between ACWR and injury risk.

METHODS

Included studies were critically appraised using the Downs and Black checklist, and a level of evidence was determined. Relevant data were extracted, tabulated, and synthesized.

RESULTS

Twenty-seven studies were included for review and ranged in percentage quality scores from 48.2% to 64.3%. Almost perfect interrater agreement (κ = 0.885) existed between raters. This review found a high variability between studies with different variables studied (total distance versus high speed running), as well as differences between ratios analyzed (1.50-1.80 versus ≥1.50), and reference groups (a reference group of 0.80-1.20 versus ≤0.85).

CONCLUSION

Considering the high variability, it appears that utilizing ACWR for external (eg, total distance) and internal (eg, heart rate) loads may be related to injury risk. Calculating ACWR using exponentially weighted moving averages may potentially result in a more sensitive measure. There also appears to be a trend towards the ratios of 0.80-1.30 demonstrating the lowest risk of injury. However, there may be issues with the ACWR method that must be addressed before it is confidently used to mitigate injury risk. Utilizing standardized approaches will allow for more objective conclusions to be drawn across multiple populations.

Profiling the metabolic fitness of a special operations police unit

OBJECTIVES

Fitness is essential to specialist police forces, who have higher occupational demands than general police, and vital to performance and mission success. However, little research has been done profiling the metabolic fitness of these units and how they compare to other populations. The objective of this study was to profile the aerobic fitness of a specialist police unit.

METHODS

Body weight was measured to account for any impact on metabolic fitness, while VO2 max was estimated via number of shuttles completed on the 20 m Progressive Shuttle Run Test (PSRT) (n=47) on two dates one calendar year apart.

RESULTS

There were no significant (p=.116) differences (mean difference 0.40±1.70 kg) in body weight between the initial measures (mean=88.84±8.25 kg) and the final measure (mean=89.24±8.77 kg) 13 months later. PSRT results increased significantly (p<.005) between the initial (mean=72.62±11.76 shuttles) and final assessments (77.51±11.46 shuttles), with a mean increase of 4.89 (± 2.94) shuttles and a small effect size (d=0.42). The mean VO2 max of the specialist police unit was 51.06±3.61 ml/min/kg following the first assessment, and 52.56±3.46 ml/min/kg following the second assessment. This was a significant finding (p<.001), with a mean difference of 1.19±1.27 ml/min/kg and a small effect size (d=0.23).

CONCLUSIONS

Elite police forces have a higher metabolic fitness than the general population and general duties police officers. Having and maintaining this fitness level is imperative for their operational success and preventing injuries. This research suggests that despite the challenges posed by operational requirements, high fitness standards can not only be maintained, but also improved.

Stress, depression, and psychoneuroimmunology

Stress is a common phenomenon most people encounter every day, whereas depression represents a vast constellation of mental disorders of multifarious etiology. Both situations have been exhaustively evaluated and scrutinized in the complex field of psychoneuroimmunology (PNI). PNI studies have attempted to ascertain and define the extensive links among and intricate web of neural activity, the endocrine system, and altered immune responses in stressed patients and those with depressive disorders. Although the literature indicates some type of relationship exists between these systems, the associations between and relevance of immune alterations in depression and stress to health and illness remain to be determined. Only by seeking to expand our knowledge of these neurological, endocrine, and immunological alterations in depressed and stressed neurological patients will our understanding of stress, depression, and health be magnified and our ability to provide holistic care be maximized.

Depression: the forgotten diagnosis among hospitalized adults

Depression, one of the most frequent of all medical disorders, is an illness that often concomitantly occurs with many other diseases in hospitalized adult patients. Sadly, overwhelming evidence suggests that comorbid depression is commonly misdiagnosed, undertreated, or not diagnosed at all when present in critically ill patients. While safe, modern, and cost-effective treatments are available for treating this disorder, comorbid depression remains a silent and unseen illness adversely affecting patient outcomes. With an understanding that this pernicious underlying illness frequently exists in hospitalized adults, nurses can identify the symptoms and patterns of comorbid depression, thereby being extremely effective in decreasing the morbidity and mortality that often accompanies this forgotten diagnosis.

Host response to autologous endothelial seeding

Dacron and expanded polytetrafluoroethylene grafts, seeded with autologous venous endothelial cells at the time of implantation, subsequently develop endothelial linings. However, it has not been shown whether the endothelial cells in these linings are derived from the seeded cells, or whether the seeding process itself stimulates host endothelial cells to proliferate and cover the grafts. As a first step in testing this hypothesis, bilateral end-to-side aortoiliac expanded polytetrafluoroethylene grafts with an internal diameter of 6 mm, an internodal distance of 22 microns, and an average length of 9.2 cm were placed in 10 adult mongrel dogs weighing 20 to 25 kg; the aorta was ligated just distal to the origin of the grafts. The graft on one side, chosen at random, was seeded with autologous endothelium that was harvested by enzyme single-stage technique from external jugular veins; the other side was not seeded. After 4 weeks the animals were anesthetized and heparinized, and the grafts were fixed by perfusion in vivo with 2.5% glutaraldehyde solution before they were removed. Both grafts occluded in two animals, and both grafts were patent in five animals. In two animals the seeded grafts were open and the unseeded grafts were occluded. In one the seeded graft was occluded and the unseeded graft was patent. There was no significant difference in clot-free surface area between seeded (29% +/- 18%) and unseeded (31% +/- 11%) grafts. Scanning electron microscopy showed the presence of an endothelial monolayer that averaged 39% +/- 20% and 36% +/- 26% coverage, respectively, in the clot-free midgraft portions of all seeded and unseeded patent grafts.(ABSTRACT TRUNCATED AT 250 WORDS)