Now showing 1 - 9 of 9
  • Publication
    Determining the relationship between linear and rotational acceleration and MPS for different magnitudes of classified brain injury risk in ice hockey
    (International Research Council on the Biomechanics of Injury (IRCOBI), 2015-09-11) ; ; ;
    Helmets have successfully decreased the incidence of traumatic brain injuries (TBI) in ice hockey, yet the incidence of concussions has essentially remained unchanged. Current ice hockey helmet certification standards use peak linear acceleration as the principal measuring helmet performance, however peak linear acceleration may not be an appropriate variable to evaluate risk at all magnitudes of brain injury. The purpose of this study is to determine the relationship between linear acceleration, rotational acceleration and maximum principal strain (MPS) for different magnitudes of classified brain injury risk in ice hockey. A helmeted and unhelmeted Hybrid III headform were impacted to the side of the head at two sites and at three velocities under conditions representing three common mechanisms of injury. Resulting linear and rotational accelerations were used as input for the University College Dublin Brain Trauma Model (UCDBTM), to calculate MPS in the brain. The resulting MPS magnitudes were used to separate the data into three groups: low risk; concussion; and TBI. The results demonstrate that the relationship between injury metrics in ice hockey impacts is dependent on the magnitude of classified injury risk and the mechanism of injury.
      399
  • Publication
    The Association among Injury Metrics for Different Events in Ice Hockey Goaltender Impact
    (International Research Council on Biomechanics of Injury (IRCOBI), 2016-09-16) ; ; ;
    Current ice hockey goaltender helmet standards use a drop test and peak linear acceleration to evaluate performance. However, ice hockey goaltenders are exposed to impacts from collisions, falls and pucks which each create unique loading conditions. As a result, the use of peak linear acceleration as a predictor for brain trauma in current ice hockey standards may not be most appropriate. The purpose of this study was to determine how kinematic response measures correlate to maximum principal strain and von Mises stress for different impact events. A NOCSAE headform was fitted with three ice hockey goaltender helmet models and impacted under conditions representing these three different impact events (fall, puck, collision). Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. Resulting accelerations were input into the University College Dublin Brain Trauma Model, which calculated maximum principal strain and von Mises stress in the cerebrum. The results demonstrated that the relationship between injury metrics in ice hockey goaltender impacts is dependent on the impact event and velocity. As a result of these changing relationships, the inclusion of finite element analysis in test protocols may provide a more practical representation of brain loading in evaluating the performance of ice hockey goaltender helmets.
      536
  • Publication
    Assessing women's lacrosse head impacts using finite element modelling
    Recently studies have assessed the ability of helmets to reduce peak linear and rotational acceleration for women's lacrosse head impacts. However, such measures have had low correlation with injury. Maximum principal strain interprets loading curves which provide better injury prediction than peak linear and rotational acceleration, especially in compliant situations which create low magnitude accelerations but long impact durations. The purpose of this study was to assess head and helmet impacts in women's lacrosse using finite element modelling. Linear and rotational acceleration loading curves from women's lacrosse impacts to a helmeted and an unhelmeted Hybrid III headform were input into the University College Dublin Brain Trauma Model. The finite element model was used to calculate maximum principal strain in the cerebrum. The results demonstrated for unhelmeted impacts, falls and ball impacts produce higher maximum principal strain values than stick and shoulder collisions. The strain values for falls and ball impacts were found to be within the range of concussion and traumatic brain injury. The results also showed that men's lacrosse helmets reduced maximum principal strain for follow-through slashing, falls and ball impacts. These findings are novel and demonstrate that for high risk events, maximum principal strain can be reduced by implementing the use of helmets if the rules of the sport do not effectively manage such situations.
      440Scopus© Citations 8
  • Publication
    Protective Capacity of Ice Hockey Helmets against Different Impact Events
    In ice hockey, concussions can occur as a result of many different types of impact events, however hockey helmets are certified using a single injury scenario, involving drop tests to a rigid surface. The purpose of this study is to measure the protective capacity of ice hockey helmets for different impact events in ice hockey. A helmeted and unhelmeted Hybrid III headform were impacted simulating falls, elbow, shoulder and puck impacts in ice hockey. Linear and rotational acceleration and maximum principal strain (MPS) were measured. A comparison of helmeted and unhelmeted impacts found significant differences existed in most conditions (p < 0.05), however some shoulder and puck impacts showed no significant difference (p > 0.05). Impacts to the ice hockey helmet tested resulted in acceleration levels below reported ranges of concussion and TBI for falls up to 5 m/s, elbow collisions, and low velocity puck impacts but not for shoulder collisions or high velocity puck impacts and falls. The helmet tested reduced MPS below reported ranges of concussion and TBI for falls up to 5 m/s but not for the other impact events across all velocities and locations. This suggests that the ice hockey helmet tested is unable to reduce engineering parameters below reported ranges of concussion and TBI for impact conditions which do not represent a drop against a rigid surface.
      766Scopus© Citations 36
  • Publication
    Comparison of Ice Hockey Goaltender Helmets for Concussion Type Impacts
    Concussions are among the most common injuries sustained by ice hockey goaltenders and can result from collisions, falls and puck impacts. However, ice hockey goaltender helmet certification standards solely involve drop tests to a rigid surface. This study examined how the design characteristics of different ice hockey goaltender helmets affect head kinematics and brain strain for the three most common impact events associated with concussion for goaltenders. A NOCSAE headform was impacted under conditions representing falls, puck impacts and shoulder collisions while wearing three different types of ice hockey goaltender helmet models. Resulting linear and rotational acceleration as well as maximum principal strain were measured for each impact condition. The results indicate that a thick liner and stiff shell material are desirable design characteristics for falls and puck impacts to reduce head kinematic and brain tissue responses. However for collisions, the shoulder being more compliant than the materials of the helmet causes insufficient compression of the helmet materials and minimizing any potential performance differences. This suggests that current ice hockey goaltender helmets can be optimized for protection against falls and puck impacts. However, given collisions are the leading cause of concussion for ice hockey goaltenders and the tested helmets provided little to no protection, a clear opportunity exists to design new goaltender helmets which can better protect ice hockey goaltenders from collisions.
      703Scopus© Citations 13
  • Publication
    Protective capacity of an ice hockey goaltender helmet for three events associated with concussion
    The purpose of this study was to assess the protective capacity of an ice hockey goaltender helmet for three concussive impact events. A helmeted and unhelmeted headform was used to test three common impact events in ice hockey (fall, puck impacts and shoulder collisions). Peak linear acceleration, rotational acceleration and rotational velocity as well as maximum principal strain and von Mises stress were measured for each impact condition. The results demonstrated the tested ice hockey goaltender helmet was well designed to manage fall and puck impacts but does not consistently protect against shoulder collisions and an opportunity may exist to improve helmet designs to better protect goaltenders from shoulder collisions.
      606Scopus© Citations 17
  • Publication
    The effect of acceleration signal processing for head impact numeric simulations
    Brain injury research in sport employs a variety of physical models equipped with accelerometers. These acceleration signals are commonly processed using filters. The purpose of this research was to determine the effect of applying filters with different cutoff frequencies to the acceleration signals used as input for finite element modelling of the brain. Signals were generated from reconstructions of concussion events from American football and ice hockey in the laboratory using a Hybrid III headform. The resulting acceleration signals were used as input for the University College Dublin Brain Trauma Model after being processed with filters. The results indicated that using a filter with a cutoff of 300 Hz or higher had little effect on the resulting strain measures. In some cases there was some effect of the filters on the peak linear (8¿30g) and rotational measures (1000¿4000 rad/s2), but little effect on the finite element strain result (approximately 2¿6 %). The short duration and high magnitude accelerations, such as the puck impact, were most affected by the cutoff frequency of different filters.
      1775Scopus© Citations 23
  • Publication
    Effect of impact surface in equestrian falls
    (International Society of Biomechanics in Sports (ISBS), 2016-07-22) ; ; ; ;
    This study examines the effect of impact surface on head kinematic response and maximum principal strain (MPS) for equestrian falls. A helmeted Hybrid III headform was dropped unrestrained onto three impact surfaces of different stiffness (steel, turf and sand) and three locations. Peak resultant linear acceleration, rotational acceleration and duration of the impact events were measured. A finite element brain model was used to calculate MPS. The results revealed that drops onto steel produced higher peak linear acceleration, rotational acceleration and MPS but lower impact durations than drops to turf and sand. However, despite lower MPS values, turf and sand impacts compared to steel impacts still represented a risk of concussion. This suggests that certification standards for equestrian helmets do not properly account for the loading conditions experienced in equestrian accidents.
      223
  • Publication
    Damage to Real World Equestrian Helmets Sustained from Impact against Different Surfaces
    (International Research Council on the Biomechanics of Injury, 2017-09-15) ; ; ;
    Concussion is one of the most common injuries in equestrian sports. Currently, the majority of the literature in equestrian head impact biomechanics has focused on the performance of helmets to rigid surfaces in order to reduce risk of injury through helmet design. Although there is a risk of sustaining in jury from impacting rigid surfaces in equestrian sport, concussions are more commonly a result of impacts to softer surfaces, such as turf. Little research has been performed to evaluate equestrian helmet’s performance for impacts to turf and, as a result, little is known about how equestrian helmets perform under common accident conditions. Differences in loading conditions have been shown to affect the protective capabilities of helmets, as helmets have been less effective at attenuating energy in impacts against highly compliant surfaces. A better understanding of how different impact surfaces influence equestrian helmet performance in real world accident conditions may provide a more effective strategy for developing a safer riding environment through improved helmet design. One method that can be used to assess helmet performance in real world conditions is to analyze damage sustained by the helmet during an impact. The purpose of this research is to evaluate the influence of impact surface on such damage during real world equestrian accidents.
      221