Ice hockey shoulder pad design and the effect on head response during shoulder-to-head impacts.

Ice hockey body checks involving direct shoulder-to-head contact frequently result in head injury. In the current study, we examined the effect of shoulder pad style on the likelihood of head injury from a shoulder-to-head check. Shoulder-to-head body checks were simulated by swinging a modified Hybrid-III anthropomorphic test device (ATD) with and without shoulder pads into a stationary Hybrid-III ATD at 21 km/h. Tests were conducted with three different styles of shoulder pads (traditional, integrated and tethered) and without shoulder pads for the purpose of control. Head response kinematics for the stationary ATD were measured. Compared to the case of no shoulder pads, the three different pad styles significantly (p < 0.05) reduced peak resultant linear head accelerations of the stationary ATD by 35-56%. The integrated shoulder pads reduced linear head accelerations by an additional 18-21% beyond the other two styles of shoulder pads. The data presented here suggest that shoulder pads can be designed to help protect the head of the struck player in a shoulder-to-head check.

Bicycle helmets are highly effective at preventing head injury during head impact: head-form accelerations and injury criteria for helmeted and unhelmeted impacts.

Cycling is a popular form of recreation and method of commuting with clear health benefits. However, cycling is not without risk. In Canada, cycling injuries are more common than in any other summer sport; and according to the US National Highway and Traffic Safety Administration, 52,000 cyclists were injured in the US in 2010. Head injuries account for approximately two-thirds of hospital admissions and three-quarters of fatal injuries among injured cyclists. In many jurisdictions and across all age levels, helmets have been adopted to mitigate risk of serious head injuries among cyclists and the majority of epidemiological literature suggests that helmets effectively reduce risk of injury. Critics have raised questions over the actual efficacy of helmets by pointing to weaknesses in existing helmet epidemiology including selection bias and lack of appropriate control for the type of impact sustained by the cyclist and the severity of the head impact. These criticisms demonstrate the difficulty in conducting epidemiology studies that will be regarded as definitive and the need for complementary biomechanical studies where confounding factors can be adequately controlled. In the bicycle helmet context, there is a paucity of biomechanical data comparing helmeted to unhelmeted head impacts and, to our knowledge, there is no data of this type available with contemporary helmets. In this research, our objective was to perform biomechanical testing of paired helmeted and unhelmeted head impacts using a validated anthropomorphic test headform and a range of drop heights between 0.5m and 3.0m, while measuring headform acceleration and Head Injury Criterion (HIC). In the 2m (6.3m/s) drops, the middle of our drop height range, the helmet reduced peak accelerations from 824g (unhelmeted) to 181g (helmeted) and HIC was reduced from 9667 (unhelmeted) to 1250 (helmeted). At realistic impact speeds of 5.4m/s (1.5m drop) and 6.3m/s (2.0m drop), bicycle helmets changed the probability of severe brain injury from extremely likely (99.9% risk at both 5.4 and 6.3m/s) to unlikely (9.3% and 30.6% risk at 1.5m and 2.0m drops respectively). These biomechanical results for acceleration and HIC, and the corresponding results for reduced risk of severe brain injury show that contemporary bicycle helmets are highly effective at reducing head injury metrics and the risk for severe brain injury in head impacts characteristic of bicycle crashes.

Towards clinical management of traumatic brain injury: a review of models and mechanisms from a biomechanical perspective.

Traumatic brain injury (TBI) is a major worldwide healthcare problem. Despite promising outcomes from many preclinical studies, the failure of several clinical studies to identify effective therapeutic and pharmacological approaches for TBI suggests that methods to improve the translational potential of preclinical studies are highly desirable. Rodent models of TBI are increasingly in demand for preclinical research, particularly for closed head injury (CHI), which mimics the most common type of TBI observed clinically. Although seemingly simple to establish, CHI models are particularly prone to experimental variability. Promisingly, bioengineering-oriented research has advanced our understanding of the nature of the mechanical forces and resulting head and brain motion during TBI. However, many neuroscience-oriented laboratories lack guidance with respect to fundamental biomechanical principles of TBI. Here, we review key historical and current literature that is relevant to the investigation of TBI from clinical, physiological and biomechanical perspectives, and comment on how the current challenges associated with rodent TBI models, particularly those involving CHI, could be improved.

Incidence of thoracic and lumbar spine injuries for restrained occupants in frontal collisions.

The increased utilization of three-point restraint systems has greatly reduced the incidence of spinal injuries in motor vehicle accidents. Nevertheless, several studies which rely upon the National Automotive Sampling System (NASS) have documented lower thoracic and upper lumbar fractures in restrained occupants involved in frontal collisions of moderate severities. Although it has been postulated that the injury mechanism may be related to the occupant being out-of-position or sitting in an unusual posture, conclusions with regard to the precise mechanism of injury are difficult due to the lack of information contained in the NASS database. In addition, previous studies have not reported statistical significance of these injuries. In this study, we combined statistical analysis of frontal collisions in the NASS database with the analysis of data acquired from sled and crash tests, which utilized anthropomorphic test devices (ATDs), in order to evaluate the incidence and potential injury mechanisms underlying thoracic and lumbar spine fractures in moderate frontal impacts. In the first portion of the study, we performed a statistical analysis of the NASS database to estimate the incidence rate of spinal fracture. This was complemented with measurements and analysis of lumbar spine load data derived from frontal sled and crash tests. Analysis of the NASS database demonstrated that thoracolumbar spinal injuries are rare when an occupant is restrained by a lap and shoulder belt, and are often accompanied by abdominal injury. The spinal loads measured during frontal impacts with restrained and nominally positioned ATDs were found to be well below injury thresholds. Our results also suggest that the potential for isolated fracture is increased when the geometry of occupant-to-restraint interaction is compromised, as occurs when an occupant submarines the lap belt.