Search

This paper aims to review the recent progress in the research carried out by scientists worldwide regarding American Footballers' head injuries and head protective equipment, focusing on the role of computation methods, mainly finite element method application to American Football helmet design and testing as well as head injury biomechanics. The helmet technology has been constantly improved, and it is driven by market competition, medical records, coaches and athletes' self-awareness. With finite element analysis and computational resources development, it is possible to develop more accurate brain models to recreate American Footballers' head impacts. This method seems to be an excellent simulation tool to verify the helmet's ability to absorb energy and enable the researchers to have an insight into head kinematics and tissue-level injuries. The work is focused on head injuries in American Football as the sport becomes more popular across the globe. Additionally, a reference to the development and newest technology is presented. The review's proposed approach gathers studies presented within the last decade regarding the coupling of finite element brain models with helmets in standardised or on-field conditions. The synthesis of the existing state of the art may enhance the researchers to continue investigating the athlete's trauma and improve the protective gear technology to minimise head injuries. The authors presented numerous studies regarding concussions and the newest findings from the last decade, including Finite Element Head models (FEHm) with American Football helmet simulations. All the studies were searched through Google Scholar, Scopus and ResearchGate databases.

Brain damage is a serious economic and social burden. Contact sports such as American football, are one of the most common sources of concussions. The biomechanical response of the head–helmet system caused by dynamic loading plays a major role. The literature has focused on measuring the resultant kinematics that act on the head and helmet during tackles. However, few studies have focused on helmet validation tests, supported by recent findings and emerging numerical approaches. The future of helmet standards could benefit from insights at the level of injury mechanisms, using numerical tools to assess the helmets. Therefore, in this work, a numerical approach is employed to investigate the influence of intracranial pressure (ICP) on brain pathophysiology during and after helmeted impacts, which are common in American football. The helmeted impacts were performed at several impact locations according to the NOCSAE standard (configurations A, AP, B, C, D, F, R, UT). In order to evaluate the ICP levels, the αHEAD finite element head and brain model was combined with a Hybrid III-neck structure and then coupled with an American football helmet to simulate the NOCSAE impacts. In addition, the ICP level was analyzed together with the resulting HIC value, since the latter is commonly used, in this application and others, as the injury criterion. The obtained results indicate that ICP values exceed the common threshold of head injury criteria and do not correlate with HIC values. Thus, this work raises concern about applying the HIC to predict brain injury in American football direct head impacts, since it does not correlate with ICP predicted with the FE head model.

The study of symmetrical and non-symmetrical effects in physics, mathematics, mechanics, medicine, and numerical methods is a current topic due to the complexity of the experiments, calculations, and virtual simulations. However, there is a limited number of research publications in computational biomechanics focusing on the symmetry of numerical head models. The majority of the models in the researched literature are symmetrical. Thus, we stated a hypothesis wherever the symmetrical models might be more applicable in numerical analysis. We carried out in-depth studies about head symmetry through clinical data, medical images, materials models, and computer analysis. We concluded that the mapping of the entire geometry of the skull and brain is essential due to the significant differences that affect the results of numerical analyses and the possibility of misinterpretation of the tissue deformation under mechanical load results.