Development of a test method for adult ice hockey helmet evaluation

Quantifying the effects of ice hockey upper body pads on mobility and comfort

Ice hockey is a high-intensity sport in which pads such as shoulder and elbow pads (S/EPs) are necessary to help players avoid injury. However, they can also affect mobility and comfort, thereby affecting players' on-ice performance. We aimed to quantify the effects of S/EPs on mobility and comfort by comparing the range of motion (ROM) of nine elite college-level ice hockey players performing static (nine single-DOF upper-body movements) and dynamic (wrist and slap shots) tasks under six pad conditions (no S/EPs and five types of S/EPs). We also analyzed the relationship between ROM and subjective comfort to provide an objective comfort evaluation of hockey pads. Five types of S/EPs restrict ROM at different levels, imposing additional mobility restrictions. We found significant differences among the five types and a high correlation between comfort and ROM. We conducted a comprehensive evaluation of the impact of ice hockey pads on mobility and comfort.

Evaluation of two rotational helmet technologies to decrease peak rotational acceleration in cycling helmets

The risk of brain trauma has been associated with the rotational kinematics leading to the development of helmets with a variety rotational management technologies. The purpose of this paper was to employ a rotation specific test protocol to evaluate the effectiveness of two of these technologies. Dynamic response of the head was measured to assess the performance of each technology. Three cycling helmets with identical construction were included in this study. One helmet with no rotational technology, an established, commercial technology and a novel helmet rotational technology designed and assembled by the authors were tested. A drop test onto a 45° anvil was used to measure the ability of each helmet to manage the dynamic response of the head form during a series of impacts. The results revealed both rotational helmet technologies resulted in lower peak rotational acceleration and brain strain, however each technology demonstrated unique performance characteristics depending on the impact condition.

The cushioning function of woodpecker's jaw apparatus during the pecking process

Woodpeckers can withstand a fierce impact during pecking without any brain injury. Although directly involved in the whole pecking, the role of the jaw apparatus played in the impact-resistant process of woodpeckers is still not fully clear. We employed finite element analysis, impact tests in vivo, and post-traumatic brain anatomical observation to evaluate the protective function of the jaw apparatus. Forehead impact model and beaks impact without quadrate joints model were selected as control groups. The maximum impact force, the maximum stress of skull, the maximum strain and strain rate of brain were employed as the main parameters for comparison. The simulations showed that: the impact force, the skull's maximum von Mises stress, the brain's maximum principal strain and the principal strain rate increased by 72%, 24%, 148% and 106%, when the forehead rather than beaks were impacted; while they increased by 23%, 74%, 116% and 72% in the beaks impact without quadrate joints model. The results of simulations were supported by the anatomical observation: brain injury was not found after beak impact tests; serious hyperaemia, bleeding, and contra-coup injury were observed after forehead impact tests. This study discovered that the jaw apparatus acted as a cushion during the pecking process and the quadrate bone and joints changed the type of load and prolonged the acting time, which reduced the impact load acted on the skull and brain. This study would provide new inspirations to develop the device for brain protection, bio-inspired structure and material for energy-absorbing.