Effects of surface compliance on the dynamic response and strains sustained by a player’s helmeted head during ice hockey impacts

2019 ◽  
Vol 234 (1) ◽  
pp. 98-106
Author(s):  
Santiago de Grau ◽  
Andrew Post ◽  
T Blaine Hoshizaki ◽  
Michael D Gilchrist
Keyword(s):  
Brain Injury ◽  
Dynamic Response ◽  
Ice Hockey ◽  
Principal Strain ◽  
Rotational Acceleration ◽  
High Compliance ◽  
Maximum Principal Strain ◽  
Hockey Players ◽  
Dependent Variables ◽  
Hybrid Iii

In hockey, players experience different compliances during impacts to the head, from stiff ice to compliant collisions against other players. The objective of this study was to examine the effect of striking compliance in ice hockey impacts and its influence on dynamic response and brain tissue strain. Three striking caps of low, medium, and high compliances were used to impact a helmeted 50th-percentile Hybrid III headform. The headform was impacted at five locations at three velocities, representative of collision scenarios in hockey. The dependent variables, peak resultant linear and rotational acceleration as well as maximum principal strain were analyzed using a multivariate analysis of variance to determine significant differences between the compliances. The results indicated a significant effect of compliance on the responses of the headform. As expected, low-impact compliance resulted in higher linear and rotational accelerations when compared to the medium and high compliance conditions. However, while the linear and rotational acceleration responses of the medium and high compliance conditions would indicate a low chance of brain injury, the maximum principal strain magnitudes indicated a high likelihood of concussion. Medium- and high-impact compliances are a factor that has not been considered when designing and testing helmet technology in sport, with current methods reflective of low compliance surfaces, that is, those with high stiffness and rigidity. The results of this study demonstrate that an impact compliance is an important factor in producing brain injury and should be considered when certifying helmets through standard testing to mitigate the risk of brain injury.

The Influence of Neck Stiffness on Head Kinematics and Maximum Principal Strain Associated With Youth American Football Collisions

2021 ◽  
pp. 1-8
Author(s):  
Janie Cournoyer ◽  
David Koncan ◽  
Michael D. Gilchrist ◽  
T. Blaine Hoshizaki
Keyword(s):  
American Football ◽  
Principal Strain ◽  
Neck Stiffness ◽  
Head Impacts ◽  
Head Kinematics ◽  
Upper Trapezius ◽  
Maximum Principal Strain ◽  
Direct Head ◽  
Hybrid Iii ◽  
Neck Strength

Understanding the relationship between head mass and neck stiffness during direct head impacts is especially concerning in youth sports where athletes have higher proportional head mass to neck strength. This study compared 2 neck stiffness conditions for peak linear and rotational acceleration and brain tissue deformations across 3 impact velocities, 3 impact locations, and 2 striking masses. A pendulum fitted with a nylon cap was used to impact a fifth percentile hybrid III headform equipped with 9 accelerometers and fitted with a youth American football helmet. The 2 neck stiffness conditions consisted of a neckform with and without resistance in 3 planes, representing the upper trapezius, the splenius capitis, and the sternocleidomastoid muscles. Increased neck stiffness resulted in significant changes in head kinematics and maximum principal strain specific to impact velocity, impact location, and striking mass.

scholarly journals Towards a comprehensive delineation of white matter tract-related deformation

2021 ◽  
Author(s):  
Zhou Zhou ◽  
Xiaogai Li ◽  
Yuzhe Liu ◽  
Madelen Fahlstedt ◽  
Marios Georgiadis ◽  
...  
Keyword(s):  
Brain Injury ◽  
White Matter ◽  
Shear Strain ◽  
Principal Strain ◽  
White Matter Tract ◽  
Related Strain ◽  
Normal Deformation ◽  
Fiber Tract ◽  
Fiber Tracts ◽  
Maximum Principal Strain

AbstractFinite element (FE) models of the human head are valuable instruments to explore the mechanobiological pathway from external loading, localized brain response, and resultant injury risks. The injury predictability of these models depends on the use of effective criteria as injury predictors. The FE-derived normal deformation along white matter (WM) fiber tracts (i.e., tract-oriented strain) has recently been suggested as an appropriate predictor for axonal injury. However, the tract-oriented strain only represents a partial depiction of the WM fiber tract deformation. A comprehensive delineation of tract-related deformation may improve the injury predictability of the FE head model by delivering new tract-related criteria as injury predictors. Thus, the present study performed a theoretical strain analysis to comprehensively characterize the WM fiber tract deformation by relating the strain tensor of the WM element to its embedded fiber tracts. Three new tract-related strains were proposed, measuring the normal deformation vertical to the fiber tracts (i.e., tract-vertical strain), and shear deformation along and vertical to the fiber tracts (i.e., axial-shear strain and lateral-shear strain, respectively). The injury predictability of these three newly-proposed strain peaks along with the previously-used tract-oriented strain peak and maximum principal strain (MPS) were evaluated by simulating 151 impacts with known outcome (concussion or no-concussion). The results showed that four tract-related strain peaks exhibit superior performance compared to MPS in discriminating concussion and non-concussion cases. This study presents a comprehensive quantification of WM tract-related deformation and advocates the use of orientation-dependent strains as criteria for injury prediction, which may ultimately contribute to an advanced mechanobiological understanding and enhanced computational predictability of brain injury.HighlightDeformation of white matte fiber tracts is directly related to brain injury, but only partially analyzed thus far.A theoretical derivation that comprehensively characterizes white matter tract-related deformation is conducted.Analytical formulas of three novel tract-related strains are presented.Tract-related strain peaks are better predictors for concussion than the maximum principal strain.

scholarly journals Canadian Minor Hockey Participants’ Knowledge about Concussion

2009 ◽  
Vol 36 (03) ◽  
pp. 315-320 ◽  
Author(s):  
Michael D. Cusimano ◽  
Mary L. Chipman ◽  
Richard Volpe ◽  
Peter Donnelly
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Physical Therapy ◽  
Ice Hockey ◽  
Return To Play ◽  
Educational Strategies ◽  
Greater Toronto Area ◽  
Minor League ◽  
Hockey Players ◽  
The Usa

Abstract:Background and Objectives:In Canada and the USA, ice hockey is a cause of traumatic brain injury. Post-concussive symptoms are the most important feature of the diagnosis of concussion in sports and it is recommended that athletes not return to play while still symptomatic. Lack of knowledge of concussions could therefore be one of the main detriments to concussion prevention in hockey. The purpose of this research is to describe what minor league hockey players, coaches, parents and trainers know about concussion and its management.Methods:A questionnaire to assess concussion knowledge and return to play guidelines was developed and administered to players at different competitive levels (n = 267), coaches, trainers and parents (total adults n = 142) from the Greater Toronto Area.Results:Although a majority of adults and players could identify mechanisms responsible for concussion, about one-quarter of adults and about a quarter to a half of children could not recall any symptoms or recalled only one symptom of a concussion. A significant number of players and some adults did not know what a concussion was or how it occurred. Almost half of the players and a fifth of the adults incorrectly stated that concussion was treated with medication or physical therapy. Nearly one quarter of all players did not know if an athlete experiencing symptoms of concussion should continue playing.Conclusions:This study demonstrated that a significant number of people held misconceptions about concussion in hockey which could lead to serious health consequences and creates a need for better preventive and educational strategies.

The development of a threshold curve for the understanding of concussion in sport

Trauma ◽  
2016 ◽  
Vol 19 (3) ◽  
pp. 196-206 ◽  
Author(s):  
T Blaine Hoshizaki ◽  
Andrew Post ◽  
Marshall Kendall ◽  
Janie Cournoyer ◽  
Philippe Rousseau ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Narrow Range ◽  
Rotational Acceleration ◽  
Threshold Curve ◽  
Head Protection ◽  
Hybrid Iii ◽  
Tolerance Curve ◽  
Minor Traumatic Brain Injury ◽  
Standard Development

Much of what is known concerning human brain injury thresholds is based upon impacts to cadavers and animal models that were used to generate the Wayne State Concussion Tolerance Curve (WSTC) and similar curves. These curves are the foundation for predictive metrics used in standard development as well as helmet design. These curves were based upon a very narrow range of impacts; impacts whose characteristics differ greatly from how the head is impacted in sport. This research examines the uses of time-based curves like the WSTC in the context of understanding mechanisms of brain injury and head protection. Published linear/rotational acceleration magnitude/duration data from Hybrid III laboratory reconstructions of brain injury events were plotted. This research further develops the understanding of injury thresholds in comparison to threshold curves such as the WSTC and Brain Injury Curve Leuven. The data demonstrate the relationships between magnitude and duration of dynamic response on minor traumatic brain injury (mTBI) in sport.

Positional Performance Profiling of Elite Ice Hockey Players

2006 ◽  
Vol 1 (2) ◽  
pp. 84-94 ◽  
Author(s):  
Jason D. Vescovi ◽  
Teena M. Murray ◽  
Jaci L. VanHeest
Keyword(s):  
Vertical Jump ◽  
Anaerobic Capacity ◽  
Cross Sectional Study ◽  
Ice Hockey ◽  
Upper Body ◽  
Fat Percentage ◽  
Cross Sectional ◽  
Hockey Players ◽  
Dependent Variables ◽  
Anthropometric Characteristics

Purpose:The primary purpose of this study was to determine whether positional profiling is possible for elite ice hockey players by examining anthropometric characteristics and physiological performance. In addition, performance ranges and percentiles were determined for each position (forwards, defensemen, and goalkeepers) on all dependent variables.Methods:A retrospective, cross-sectional study design was used with performance data from ice hockey players (mean age = 18.0 ± 0.6 years) attending the 2001 (n = 74), 2002 (n = 84), and 2003 (n = 92) Combines. Four anthropometric characteristics and 12 performance tests were the dependent variables. A 3 × 3 (position × year) 2-way ANOVA was used to determine whether any significant interactions were present. No significant interactions were observed, so the data were collapsed over the 3-year period and positional characteristics were analyzed using a 1-way ANOVA.Results:Defenders were heavier and/or taller compared with the other 2 positions (P ≤ .01), whereas goalkeepers showed greater body-fat percentage compared with that of forwards (P = .001). It was found that goalkeepers had significantly lower strength measures for the upper body (P ≤ .043) and lower anaerobic capacity (P ≤ .039) values compared with at least one other position, but they had greater flexibility (P ≤ .013). No positional differences were observed for the broad jump, vertical jump, aerobic power, or curl-ups.Conclusion:The current findings provide evidence supporting the use of anthropometric measurements, upper body strength, and anaerobic capacity to effectively distinguish among positions for elite-level ice hockey players.

scholarly journals Blood Biomarkers for Brain Injury in Concussed Professional Ice Hockey Players

2014 ◽  
Vol 71 (6) ◽  
pp. 684 ◽  
Author(s):  
Pashtun Shahim ◽  
Yelverton Tegner ◽  
David H. Wilson ◽  
Jeffrey Randall ◽  
Tobias Skillbäck ◽  
...  
Keyword(s):  
Brain Injury ◽  
Ice Hockey ◽  
Blood Biomarkers ◽  
Hockey Players

scholarly journals THE EFFECT OF A BODY CHECKING RULE CHANGE ON HEAD IMPACT BIOMECHANICS IN BANTAM ICE HOCKEY ATHLETES

2020 ◽  
Vol 8 (4_suppl3) ◽  
pp. 2325967120S0021
Author(s):  
Patricia R. Combs ◽  
Cassie B. Ford ◽  
Elizabeth F. Teel ◽  
Erin B. Wasserman ◽  
Michael J. Cools ◽  
...  
Keyword(s):  
Injury Risk ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Rotational Acceleration ◽  
Body Checking ◽  
Head Impacts ◽  
Head Impact Biomechanics ◽  
Impact Biomechanics ◽  
Hockey Players

Background: Body checking is the most common injury mechanism in ice hockey. Rule changes have sought to mitigate body checking exposure among youth players. In 2011, USA Hockey changed the legal body checking age from Pee Wee (11/12-year-olds) to Bantam (13/14-year-olds). Interestingly, Bantam players with checking experience during Pee Wee had a lower concussion risk relative to Bantam players without checking experience in a sample of Canadian youth hockey players. Understanding the head impact biomechanics underlying these findings could further elucidate the consequences of this rule change. Purpose: To determine the association between Pee Wee checking exposure and head impact biomechanics in a cohort of Bantam players. Methods: We prospectively collected data on Bantam ice hockey players during the 2006/07-2009/10 seasons and the 2012-2013 season. The 2006/07-2009/10 cohort (n= 61, age=13.9±0.5 years, height=168.2±8.7 cm, mass=59.9±10.4 kg) was allowed to body check (BC) as a Pee Wee player. The 2012-2013 cohort (n=15, age=13.3±0.4 years, height=167.5±7.4 cm, mass=57.5±8.6 kg) was not permitted to body check (NBC) as a Pee Wee player. Over the course of each season, head impacts were measured using in-helmet accelerometers. Only head impacts with linear acceleration ≥10 g were included in our analysis. Main outcome measures were mean linear acceleration (g) and rotational acceleration (rad/s2). Levene’s tests assessed equality of variance between groups. We employed mixed effects models to assess group differences in mean linear and rotational acceleration between BC and NBC groups. Results: The BC and NBC groups did not differ in height (t74=0.28, p=0.78) or mass (t74=0.84, p=0.40). When assessing group differences in head impact biomechanics, the NBC experienced significantly greater linear acceleration (F1,74=4.36, p=0.04) and greater rotational acceleration (F1,74=21.2, p<0.001) relative to the BC group. On average, the NBC group experienced 23.1 ± 0.87 g linear acceleration and 1993.5 ± 68.4 rad/s2 rotational acceleration compared to the BC group, which experienced 21.2 ± 0.30 g linear acceleration and 1615.9 ± 45.2 rad/s2 rotational acceleration. Conclusions: Bantam ice hockey players without body checking experience during their Pee Wee years experienced greater average linear and rotational acceleration relative to players with Pee Wee body checking experience. While removing body checking from Pee Wee ice hockey may reduce short-term injury risk, these athletes may demonstrate more high-risk head impact biomechanics when legally allowed to body check. Future research should continue to examine the influence of policy changes on head impact biomechanics and injury risk in youth ice hockey. [Figure: see text]

Comparison of dynamic response and maximum principal strain of diagnosed concussion in professional men’s rugby league

2021 ◽  
pp. 175433712110165
Author(s):  
Talia Ignacy ◽  
Andrew Post ◽  
Andrew J Gardner ◽  
Michael D Gilchrist ◽  
Thomas Blaine Hoshizaki
Keyword(s):  
Dynamic Response ◽  
Rugby League ◽  
Principal Strain ◽  
Response Data ◽  
Maximum Principal Strain ◽  
Long Duration ◽  
High Incidence ◽  
Trauma Model ◽  
The University ◽  
The Brain

Rugby league has been identified as a contact sport with a high incidence of concussion. Research has been conducted to describe incidence and mechanisms of concussion in rugby league, however the risks associated with injury events (shoulder, hip, head to head) are unknown. The purpose of this study was to describe the common injury events leading to concussion in the National Rugby League and compare these events through analysis of dynamic response and brain tissue deformation. Twenty-seven impact videos of concussive injuries were physically reconstructed to obtain linear and rotational accelerations of the head. Dynamic response data were input into the University College Dublin Brain Trauma Model (UCDBTM) to calculate maximum principal strain (MPS). Head-to-head events produced a short duration event with an average peak linear and peak rotational acceleration of 205 g and 15,890 rad/s2, respectively, which were significantly greater than the longer duration hip-to-head (24.7 g and 2650 rad/s2) and shoulder-to-head (24.2 g and 3280 rad/s2) impacts. There were no differences in MPS between events. These results suggest that risk of strain to the brain may be produced by short and long duration acceleration events. Thus, both of these accelerations need to be accounted for in the development of improved head and body protection in rugby. In addition, this data demonstrates that these events cause a risk of concussion requiring efforts to limit or modify how energy is transferred to the head.

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