J. Michio Clark

A comparison of the capacity of ice hockey goaltender masks for the protection from puck impacts

Abstract Goaltenders in ice hockey are the only players that are on the ice for the entire game. Their position exposes them to impacts from collisions with other players, falls to the ice, and puck impacts. In competitive ice hockey leagues, head injuries resulting from puck impacts have been reported with some cases resulting in ending the player’s career. Considerable research has been conducted to assess the performance of hockey helmets; however, few have assessed the performance of goaltenders’ masks. The purpose of this study was to compare the capacity of four goaltenders’ masks for the protection from puck impact as measured by head acceleration and peak force. A Hybrid III headform was fitted with four different goaltender masks and impacted with a hockey puck in three locations at 25 m/s. The masks were found to vary in the level of protection they offered as the mask with the thickest liner resulted in lower forces than the thinnest mask for side impacts; however, the thinnest mask resulted in the lowest force for front impacts. Despite performance differences at specific locations, no one mask proved to be superior as peak acceleration and peak force values did not exceed the thresholds necessary for concussion.

Protective capacity of an ice hockey goaltender helmet for three events associated with concussion

Abstract 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.

The Ability of Men’s Lacrosse Helmets to Reduce the Dynamic Impact Response for Different Striking Techniques in Women’s Field Lacrosse

Background: Women’s field lacrosse is described as a noncontact game relying primarily on rules to decrease the risk of head injuries. Despite not allowing head contact, however, concussions continue to be reported in women’s field lacrosse. Purpose: To assess the ability of men’s lacrosse helmets to decrease linear and angular acceleration for different striking techniques in women’s field lacrosse. Study Design: Controlled laboratory study. Methods: A helmeted and unhelmeted Hybrid III 50th Percentile headform was attached to a Hybrid III neckform and were subjected to impacts by 8 striking techniques. Eleven athletic females completed 5 slashing techniques, while physical reconstruction equipment was used to simulate falls and shoulder and ball impacts to the head. Three trials were conducted for each condition, and peak resultant linear and angular accelerations of the headform were measured. Results: Falls produced the highest linear and angular acceleration, followed by ball and high-velocity stick impacts. Low-velocity stick impacts were found to produce the lowest linear and angular accelerations. Men’s lacrosse helmets significantly decreased linear and angular accelerations in all conditions, while unhelmeted impacts were associated with high accelerations. Conclusion: If women’s field lacrosse is played within the rules, only falls were found to produce high linear and angular acceleration. However, ball and high-velocity stick impacts were found to produce high linear and angular accelerations. These linear and angular accelerations were found to be within the ranges reported for concussion. When the game is not played within the rules, men’s lacrosse helmets provide an effective method of reducing linear and angular accelerations. Thus, women’s field lacrosse may be able to reduce the occurrence of high linear and angular acceleration impacts by having governing bodies improving rules, implementing the use of helmets, or both. Clinical Relevance: Identifying striking techniques that produce high linear and angular acceleration specific to women’s lacrosse and measuring the capacity of a men’s lacrosse helmet to reduce linear and angular acceleration.

Event-specific impact test protocol for ice hockey goaltender masks

ABSTRACT Goaltenders in the sport of ice hockey are at high risk for concussions from falls to the ice, player collisions and puck impacts. However, current methods used to certify helmets only consider head accelerations for drop tests which may not describe all common injury mechanisms relating to concussion. The purpose of this study was to describe the characteristics of 3 events associated with concussions for ice hockey goaltenders. A helmeted medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was impacted under conditions representing 3 injury events. Three impact locations’ velocities were selected for each event based on video analysis of real-world concussive events. Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. Each impact event produced a unique dynamic response and brain stress and strain values. This demonstrates that a single impact event (i.e. falls) cannot adequately describe all impact events. As a result, impact protocols which assess multiple impact events such as the protocol described in this study should be used to evaluate ice hockey goaltender masks.

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 womens 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 womens lacrosse using finite element modelling. Linear and rotational acceleration loading curves from womens 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 mens 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.

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.