Analysis of HIC and Hydrostatic Pressure in the Human Head during NOCSAE Tests of American Football Helmets

Abstract

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.

Physiological and Biomechanical Monitoring in American Football Players: A Scoping Review

“…Studies on CM aimed to create new test protocols and metrics to screen the safety of equipment [ 92 , 93 , 97 , 102 ], develop and validate new tools and technologies [ 91 , 96 , 98 , 99 ], study the interaction between neck muscle activation and head impacts [ 95 , 100 ], and study the strain on the brain during practices and games [ 103 ] In Table 4 , data regarding studies related to CM are summarized.…”

“…It was found that the most important branches of research on the studied topic were biomechanical studies regarding injuries encompassing concussions [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 ], footwear [ 105 ...…”

“…The issue related to the identification of sub-concussive events remains an open problem in the literature. Additionally, the description of concussion occurrence by only linear acceleration is limited [ 51 , 71 , 102 ]. The single use of metrics (such as the Gadd severity index or head injury criterion) is not adequate because they are only associated with linear acceleration, whereas rotational acceleration seems to play an essential role in the identification of concussions [ 93 , 97 ].…”

Design and Virtual Testing of American Football Helmets–A Review

“…Dymek et al [70] presented a different approach, where the ICP is investigated in 8 different NOCSAE setups. Additionally, the ICP calculated with the αHEAD model is compared to the Head Injury Criterion (HIC) calculated with the Hybrid III Head-Neck model.…”

The Application of Microelectromechanical Systems (MEMS) Accelerometers to the Assessment of Blast Threat to Armored Vehicle Crew

“…Traumatic brain injury is a severe condition, for which the main cause is excessive mechanical loading during vehicle accidents, sports injuries, violence, or injuries related to everyday activities (e.g., impact with furniture or falls down stairs) [ 27 , 28 , 29 , 30 , 31 ]. Asymmetry within military action zones characterizes actions which differ from those of a stronger enemy, the aim of which being to increase dominance, exploit the weaknesses of the stronger enemy, seize initiative, and gain increased freedom of action [ 32 , 33 , 34 , 35 ].…”