Minimum depths to essential structures in a UK military population using computed tomography: application to stab-resistant body armour

The 21-foot principle: Effects of age and sex on knife attack characteristics

INTRODUCTION

Knives are commonly-used weapons in criminal activities and interpersonal assaults worldwide. Injury reports have identified the upper body as the most frequent location of knife injuries, and that stabbing attacks are more fatal than slashing attacks. The first two aims of the study explore whether the type of attack and attack location could be predicted from age and sex group. The following aims compared attack times between sex and age groups and evaluated the influence of subject characteristics on attack duration. The exploratory aim surveyed subjects on attack location during the scenario if the target was not wearing body armor.

METHODS

A total of 74 subjects (male: n = 40; female: n = 34) participated. Subjects were video recorded during a 21-foot (ft) attack and participated in follow-up questions and completed a push-up test to determine physical strength. Attack time (AT), concealment location, attack type, and demographic information were correlated to age group and sex.

RESULTS

Mean AT from 21 ft was 2.40 ± 0.47 s, with the fastest of 1.75 s. The most commonly observed concealment location, attack type, and attack location on the target included the right hip (n = 62), stab (n = 62), and the chest (n = 28), respectively. After controlling for push-up ability (p < 0.05), no differences were reported between any combination of sex and age group in AT from 21 ft. Push-up ability was the sole significant predictor of AT from 21 ft (p < 0.05). Twenty-eight subjects reported they purposely avoided the body armor vest during the 21 ft attack.

CONCLUSION

Law enforcement officers are encouraged to train for quick defensive or offensive responses, such as hand-to-knife combat or rapid firearm skills that can be performed in under 1.75 s. Stronger people were predicted to complete the 21 ft attack faster.

Injury modelling for strategic planning in protecting the national infrastructure from terrorist explosive events

Terrorist events in the form of explosive devices have occurred and remain a threat currently to the population and the infrastructure of many nations worldwide. Injuries occur from a combination of a blast wave, energised fragments, blunt trauma and burns. The relative preponderance of each injury mechanism is dependent on the type of device, distance to targets, population density and the surrounding environment, such as an enclosed space, to name but a few. One method of primary prevention of such injuries is by modification of the environment in which the explosion occurs, such as modifying population density and the design of enclosed spaces. The Human Injury Predictor (HIP) tool is a computational model which was developed to predict the pattern of injuries following an explosion with the goal to inform national injury prevention strategies from terrorist attacks. HIP currently uses algorithms to predict the effects from primary and secondary blast and allows the geometry of buildings to be incorporated. It has been validated using clinical data from the '7/7' terrorist attacks in London and the 2017 Manchester Arena terrorist event. Although the tool can be used readily, it will benefit from further development to refine injury representation, validate injury scoring and enable the prediction of triage states. The tool can assist both in the design of future buildings and methods of transport, as well as the situation of critical emergency services required in the response following a terrorist explosive event. The aim of this paper is to describe the HIP tool in its current version and provide a roadmap for optimising its utility in the future for the protection of national infrastructure and the population.

Ergonomic impact of prehospital clinicians using body armour: A qualitative study

Armed crime constitutes a significant number of offences in England. The associated healthcare burden forms 32% of the workload of London HEMS, requiring these clinicians to use body armour. Much research has explored the ergonomic impact of body armour in police and military populations however the impact on prehospital clinicians is not known. The aim of this study is to explore the perceptions of prehospital clinicians of wearing body armour.Focus groups were conducted until theoretical saturation was reached, utilising hermeneutic phenomenology.Problems with the comfort, safety, time, hygiene, coverage, and female fit of armour were identified. Clinicians feel hot in summer, time to respond to scenes is increased and the fit for females is poor.Consideration should be given to sourcing specific female-fit armour and to the interoperability with the rest of the protective clothing. A redesign of uniform could provide greater flexibility to mitigate some of the issues.

Gelatine Backing Affects the Performance of Single-Layer Ballistic-Resistant Materials Against Blast Fragments

Penetrating trauma by energized fragments is the most common injury from explosive devices, the main threat in the contemporary battlefield. Such devices produce projectiles dependent upon their design, including preformed fragments, casings, glass, or stones; these are subsequently energized to high velocities and cause serious injuries to the body. Current body armor focuses on the essential coverage, which is mainly the thoracic and abdominal area, and can be heavy and cumbersome. In addition, there may be coverage gaps that can benefit from the additional protection provided by one or more layers of lightweight ballistic fabrics. This study assessed the performance of single layers of commercially available ballistic protective fabrics such as Kevlar^®, Twaron^®, and Dyneema^®, in both woven and knitted configurations. Experiments were carried out using a custom-built gas-gun system, with a 0.78-g cylindrical steel fragment simulating projectile (FSP) as the impactor, and ballistic gelatine as the backing material. FSP velocity at 50% risk of material perforation, gelatine penetration, and high-risk wounding to soft tissue, as well as the depth of penetration (DoP) against impact velocity and the normalized energy absorption were used as metrics to rank the performance of the materials tested. Additional tests were performed to investigate the effect of not including a soft-tissue simulant backing material on the performance of the fabrics. The results show that a thin layer of ballistic material may offer meaningful protection against the penetration of this FSP. Additionally, it is essential to ensure a biofidelic boundary condition as the protective efficacy of fabrics was markedly altered by a gelatine backing.