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.

Law enforcement is an intermittently physically demanding job, interspersed with long periods of sedentary activity. To prepare for the physical demands of the job, law enforcement agencies enlist recruits into academies with a focus on physical training. Often, academies focus on aerobic-based exercise despite anaerobic fitness being strongly correlated to occupational tasks. The objective of this article is to analyze the changes in the fitness of police recruits during academy training. Initial and final fitness test results, encompassing muscular power, strength, endurance as well as aerobic and anaerobic fitness, were measured to analyze changes in fitness. Dependent t-tests showed significant increases (p < 0.05) across all fitness tests, with a trend towards larger increases in aerobic and muscle-endurance-based tests. Recruits from this academy tended to have higher fitness results compared to other academies and were either average or below average compared to age-matched standards in the general population. Physical training should persist for recruits beyond the academy to continue to develop fitness throughout their career. Academies should add a focus on muscular strength and power training as these measures relate to occupational tasks, which may better prepare recruits for demands they will be expected to face in the field.

Tactical populations often participate in demanding physical training and perform strenuous workplace tasks, increasing injury risk. Mitigating injury risk is vital for maintaining trained personnel and should be a focus for tactical populations. One such method, tracking training load, has not been studied in-depth in tactical populations, despite documented effectiveness in elite sport. Most injuries to tactical personnel are overuse in nature and therefore may be prevented by optimizing training load. A c c e p t e d While the methods used in elite sport may not be directly transferrable to tactical environments, they may be used to inform injury mitigation strategies in tactical populations.

Firefighter clothing is known to restrict movement and increase the risk of musculoskeletal injury. The aim of this study was to investigate differences between clothing variations and firefighter mobility. Data were collected from eight firefighters using a randomized counterbalanced, repeated measures, design. Three different clothing variants (V1-V3) in addition to current station wear (S) were trialed. Combinations of S and V1 (SV1) and V2 (SV2) were also trialed. Outcome measures included: standing reach height; the Functional Movement Screen [FMS]; vertical jump; a visual analogue scale [VAS] for the FMS, vertical jump, step ups and crawl; and a mannequin sketch to mark areas of discomfort. V3 was preferred over S in all tasks and performed better both objectively (FMS and vertical jump) and subjectively (VAS scores). While V1 was typically associated with poorer performance, the impacts of V1 and V2 when compared to each other and S varied depending on the tasks performed. This variation was greater when V1 or V2 were worn with S (SV1 and SV2). Areas of discomfort across all variations was the knees, followed by the thighs. Clothing that has the least impact on, or improves, mobility (especially around the lower limbs) may help reduce firefighter injury and limit subjective discomfort.Safety 2019, 5, 78 2 of 18 while stepping over it. Conversely, in wildland firefighters, a 15 kg pack was found to significantly increase their time to negotiate escape routes during a wilderness fire forced evacuation [14].In addition to the load weights, the nature of the equipment and clothing worn by firefighters is thought to impact both their performance and injury risk. The bulkiness and rigidity of the PPE clothing worn by firefighters, for example, is known to reduce their mobility and has been considered to increase the risk of injury through increasing the potential for a slip, trip or fall [2,3,15]. SCBA and boot sizes (heights), in particular, have been associated with reducing mobility, increasing physical stress, and increasing the risk of slips, trips, and falls (3). As such, it is not surprising that the wearing of SCBA and boots are major contributors to fireground musculoskeletal injuries [3].Given that slips, trips, and falls are a common mechanism for firefighter injuries to occur, and that the PPE worn by firefighters can increase their risk of a slip, trip, or fall, research investigating the impacts of different firefighter PPE clothing variations on their mobility may be of value and provide a means of optimising clothing design and development in order to mitigate these injuries. Furthermore, as not all injuries occur while performing fire suppression tasks, the impacts of different firefighter clothing in general (e.g., daily station wear) on mobility may be of value. However, there is no known research comparing different clothing variations and firefighter mobility specifically. As such, the aim of this research was to compare the impacts on firefighter mobility of three different clothing variati...

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.