scholarly journals Accident reconstructions of falls, collisions, and punches in sports

2020 ◽  
Vol 4 ◽  
pp. 205970022093695
Author(s):  
Marshall Kendall ◽  
Anna Oeur ◽  
Susan E Brien ◽  
Michael Cusimano ◽  
Shawn Marshall ◽  
...  
Keyword(s):  
Finite Element ◽  
Brain Tissue ◽  
Ice Hockey ◽  
American Football ◽  
External Loading ◽  
Loading Conditions ◽  
Head Impacts ◽  
Impact Parameters ◽  
Impact Events ◽  
Impact Mass

Objective Impacts to the head are the primary cause of concussive injuries in sport and can occur in a multitude of different environments. Each event is composed of combinations of impact characteristics (striking velocity, impact mass, and surface compliance) that present unique loading conditions on the head and brain. The purpose of this study was to compare falls, collisions, and punches from accident reconstructions of sports-related head impacts using linear, rotational accelerations and maximal principal strain of brain tissue from finite element simulation. Methods This study compared four types of head impact events through reconstruction. Seventy-two head impacts were taken from medical reports of accidental falls and game video of ice hockey, American football, and mixed-martial arts. These were reconstructed using physical impact systems to represent helmeted and unhelmeted falls, player-to-player collisions, and punches to the head. Head accelerations were collected using a Hybrid III headform and were input into a finite element brain model used to approximate strain in the cerebrum associated with the external loading conditions. Results Significant differences ( p < 0.01) were found for peak linear and rotational accelerations magnitudes (30–300 g and 3.2–7.8 krad/s2) and pulse durations between all impact event types characterized by unique impact parameters. The only exception was found where punch impacts and helmeted falls had similar rotational durations. Regression analysis demonstrated that increases to strain from unhelmeted falls were significantly influenced by both linear and rotational accelerations, meanwhile helmeted falls, punches, and collisions were influenced by rotational accelerations alone. Conclusion This report illustrates that the four distinct impact events created unique peak head kinematics and brain tissue strain values. These distinct patterns of head acceleration characteristics suggest that it is important to keep in mind that head injury can occur from a range of low to high acceleration magnitudes and that impact parameters (surface compliance, striking velocity, and impact mass) play an important role on the duration-dependent tolerance to impact loading.

scholarly journals Spectrum of acute clinical characteristics of diagnosed concussions in college athletes wearing instrumented helmets

2012 ◽  
Vol 117 (6) ◽  
pp. 1092-1099 ◽  
Author(s):  
Ann-Christine Duhaime ◽  
Jonathan G. Beckwith ◽  
Arthur C. Maerlender ◽  
Thomas W. McAllister ◽  
Joseph J. Crisco ◽  
...  
Keyword(s):  
Collegiate Athletes ◽  
Head Impact ◽  
Ice Hockey ◽  
Future Research ◽  
Impact Event ◽  
Head Impacts ◽  
Presenting Symptoms ◽  
Wide Range ◽  
Impact Events ◽  
Specific Impact

Object Concussive head injuries have received much attention in the medical and public arenas, as concerns have been raised about the potential short- and long-term consequences of injuries sustained in sports and other activities. While many student athletes have required evaluation after concussion, the exact definition of concussion has varied among disciplines and over time. The authors used data gathered as part of a multiinstitutional longitudinal study of the biomechanics of head impacts in helmeted collegiate athletes to characterize what signs, symptoms, and clinical histories were used to designate players as having sustained concussions. Methods Players on 3 college football teams and 4 ice hockey teams (male and female) wore helmets instrumented with Head Impact Telemetry (HIT) technology during practices and games over 2–4 seasons of play. Preseason clinical screening batteries assessed baseline cognition and reported symptoms. If a concussion was diagnosed by the team medical staff, basic descriptive information was collected at presentation, and concussed players were reevaluated serially. The specific symptoms or findings associated with the diagnosis of acute concussion, relation to specific impact events, timing of symptom onset and diagnosis, and recorded biomechanical parameters were analyzed. Results Data were collected from 450 athletes with 486,594 recorded head impacts. Forty-eight separate concussions were diagnosed in 44 individual players. Mental clouding, headache, and dizziness were the most common presenting symptoms. Thirty-one diagnosed cases were associated with an identified impact event; in 17 cases no specific impact event was identified. Onset of symptoms was immediate in 24 players, delayed in 11, and unspecified in 13. In 8 cases the diagnosis was made immediately after a head impact, but in most cases the diagnosis was delayed (median 17 hours). One diagnosed concussion involved a 30-second loss of consciousness; all other players retained alertness. Most diagnoses were based on self-reported symptoms. The mean peak angular and rotational acceleration values for those cases associated with a specific identified impact were 86.1 ± 42.6g (range 16.5–177.9g) and 3620 ± 2166 rad/sec2 (range 183–7589 rad/sec2), respectively. Conclusions Approximately two-thirds of diagnosed concussions were associated with a specific contact event. Half of all players diagnosed with concussions had delayed or unclear timing of onset of symptoms. Most had no externally observed findings. Diagnosis was usually based on a range of self-reported symptoms after a variable delay. Accelerations clustered in the higher percentiles for all impact events, but encompassed a wide range. These data highlight the heterogeneity of criteria for concussion diagnosis, and in this sports context, its heavy reliance on self-reported symptoms. More specific and standardized definitions of clinical and objective correlates of a “concussion spectrum” may be needed in future research efforts, as well as in the clinical diagnostic arena.

Head Kinematics by Contact Scenarios in Youth Ice Hockey

Neurology ◽  
2020 ◽  
Vol 95 (20 Supplement 1) ◽  
pp. S1.1-S1
Author(s):  
Abigail Swenson ◽  
Logan Miller ◽  
Jillian Urban ◽  
Joel Stitzel
Keyword(s):  
Rotational Velocity ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Head Impact ◽  
Ice Hockey ◽  
Contact Sports ◽  
Head Impacts ◽  
Rigorous Study ◽  
Improving Accuracy ◽  
Impact Events

ObjectiveThe objective of this pilot study was to characterize head impact exposure in a sample of youth boys' ice hockey using a novel instrumented mouthpiece, improving accuracy.BackgroundFrom 2010 to 2018 youth ice hockey saw a 15% increase in participation, despite growing concerns for concussion risk in contact sports. While contact sports with similar rates of concussion have been subjected to rigorous study, head impact exposure in youth ice hockey has been largely underexplored. Existing youth studies have utilized helmet-mounted sensors, which are associated with error due to poor coupling with the skull.Design/MethodsCustom mouthpieces containing a tri-axial accelerometer and gyroscope were fit to seven enrolled athletes, and monitored during practices and games throughout the season. Linear acceleration and rotational velocity of the head were recorded for 60 ms when 5 g was exceeded on any axis for at least 3 ms. Time-synchronized film was reviewed to identify the contact scenario and head contact. Summary statistics of kinematics were calculated by scenario and presence of head contact.ResultsA total of 465 events were recorded over 25 weeks. Of these events 25% involved head contact; 92% of all contact scenarios were board checks, falls, or ice checks. Events involving head contact (i.e., head impacts) had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 8.1 [30.9] g, 7.9 [20.2] rad/s, and 614 [2673] rad/s2, respectively. Events not involving head contact had median [95th percentile] peak linear acceleration, rotational velocity, and angular acceleration of 6.6 [43.8] g, 6.5 [17.5] rad/s, and 455 [4115] rad/s2, respectively.ConclusionsThe majority of the recorded events could be classified as board checks, falls, or ice checks. Median peak kinematics were higher for head impacts than non-head impact events. In contrast, 95th percentile linear and angular accelerations were greater for impacts not involving head contact.

An Integrated Musculoskeletal-Finite-Element Model to Evaluate Effects of Load Carriage on the Tibia During Walking

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Chun Xu ◽  
Amy Silder ◽  
Ju Zhang ◽  
Julie Hughes ◽  
Ginu Unnikrishnan ◽  
...  
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Injury Risk ◽  
Load Carriage ◽  
Body Motion ◽  
Bone Biomechanics ◽  
External Loading ◽  
Fe Model ◽  
Loading Conditions ◽  
Reaction Forces

Prior studies have assessed the effects of load carriage on the tibia. Here, we expand on these studies and investigate the effects of load carriage on joint reaction forces (JRFs) and the resulting spatiotemporal stress/strain distributions in the tibia. Using full-body motion and ground reaction forces from a female subject, we computed joint and muscle forces during walking for four load carriage conditions. We applied these forces as physiological loading conditions in a finite-element (FE) analysis to compute strain and stress. We derived material properties from computed tomography (CT) images of a sex-, age-, and body mass index-matched subject using a mesh morphing and mapping algorithm, and used them within the FE model. Compared to walking with no load, the knee JRFs were the most sensitive to load carriage, increasing by as much as 26.2% when carrying a 30% of body weight (BW) load (ankle: 16.4% and hip: 19.0%). Moreover, our model revealed disproportionate increases in internal JRFs with increases in load carriage, suggesting a coordinated adjustment in the musculature functions in the lower extremity. FE results reflected the complex effects of spatially varying material properties distribution and muscular engagement on tibial biomechanics during walking. We observed high stresses on the anterior crest and the medial surface of the tibia at pushoff, whereas high cumulative stress during one walking cycle was more prominent in the medioposterior aspect of the tibia. Our findings reinforce the need to include: (1) physiologically accurate loading conditions when modeling healthy subjects undergoing short-term exercise training and (2) the duration of stress exposure when evaluating stress-fracture injury risk. As a fundamental step toward understanding the instantaneous effect of external loading, our study presents a means to assess the relationship between load carriage and bone biomechanics.

Repetitive Head Trauma Induces Chronic Traumatic Encephalopathy by Multiple Mechanisms

2020 ◽  
Vol 40 (04) ◽  
pp. 430-438 ◽  
Author(s):  
Jonathan D. Cherry ◽  
Katharine J. Babcock ◽  
Lee E. Goldstein
Keyword(s):  
Cognitive Deficits ◽  
Tau Protein ◽  
Chronic Traumatic Encephalopathy ◽  
Biomechanical Properties ◽  
Ice Hockey ◽  
American Football ◽  
Head Impacts ◽  
Blast Exposure ◽  
Hyperphosphorylated Tau Protein ◽  
The Brain

AbstractExposure to repetitive neurotrauma increases lifetime risk for developing progressive cognitive deficits, neurobehavioral abnormalities, and chronic traumatic encephalopathy (CTE). CTE is a tau protein neurodegenerative disease first identified in boxers and recently described in athletes participating in other contact sports (notably American football, ice hockey, rugby, and wrestling) and in military veterans with blast exposure. Currently, CTE can only be diagnosed by neuropathological examination of the brain after death. The defining diagnostic lesion of CTE consists of patchy perivascular accumulations of hyperphosphorylated tau protein that localize in the sulcal depths of the cerebral cortex. Neuronal abnormalities, axonopathy, neurovascular dysfunction, and neuroinflammation are triggered by repetitive head impacts (RHIs) and likely act as catalysts for CTE pathogenesis and progression. However, the specific mechanisms that link RHI to CTE are unknown. This review will explore two important areas of CTE pathobiology. First, we will review what is known about the biomechanical properties of RHI that initiate CTE-related pathologies. Second, we will provide an overview of key features of CTE neuropathology and how these contribute to abnormal tau hyperphosphorylation, accumulation, and spread.

scholarly journals Head impacts in a junior rugby league team measured with a wireless head impact sensor: an exploratory analysis

2017 ◽  
Vol 19 (1) ◽  
pp. 13-23 ◽  
Author(s):  
Doug King ◽  
Patria Hume ◽  
Conor Gissane ◽  
Trevor Clark
Keyword(s):  
Cohort Analysis ◽  
Linear Acceleration ◽  
Rugby League ◽  
Ice Hockey ◽  
American Football ◽  
High School Football ◽  
Head Impacts ◽  
Hockey Players ◽  
Collegiate Football ◽  
Frequency Magnitude

OBJECTIVE The aim of this study was to investigate the frequency, magnitude, and distribution of head impacts sustained by players in a junior rugby league over a season of matches. METHODS The authors performed a prospective cohort analysis of impact magnitude, frequency, and distribution on data collected with instrumented XPatches worn behind the ear of players in an “under-11” junior rugby league team (players under 11 years old). RESULTS A total of 1977 impacts were recorded. Over the course of the study, players sustained an average of 116 impacts (average of 13 impacts per player per match). The measured linear acceleration ranged from 10g to 123g (mean 22g, median 16g, and 95th percentile 57g). The rotational acceleration ranged from 89 rad/sec2 to 22,928 rad/sec2 (mean 4041 rad/sec2, median 2773 rad/sec2, and 95th percentile 11,384 rad/sec2). CONCLUSIONS The level of impact severity based on the magnitude of impacts for linear and rotational accelerations recorded was similar to the impacts reported in studies of American junior and high school football, collegiate football, and youth ice hockey players, but the players in the rugby league cohort were younger, had less body mass, and played at a slower speed than the American players. Junior rugby league players are required to tackle the player to the ground and use a different tackle technique than that used in American football, likely increasing the rotational accelerations recorded at the head.

Distribution of Brain Strain in the Cerebrum for Laboratory Impacts to Ice Hockey Goaltender Masks

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
J. Michio Clark ◽  
Andrew Post ◽  
T. Blaine Hoshizaki ◽  
Michael D. Gilchrist
Keyword(s):  
Brain Regions ◽  
Ice Hockey ◽  
Tissue Response ◽  
Loading Conditions ◽  
Impact Site ◽  
Trauma Model ◽  
The University ◽  
The Impact ◽  
Impact Events ◽  
The Brain

Concussions are among the most common injuries sustained by goaltenders. Concussive injuries are characterized by impairment to neurological function which can affect many different brain regions. Understanding how different impact loading conditions (event type and impact site) affect the brain tissue response may help identify what kind of impacts create a high risk of injury to specific brain regions. The purpose of this study was to examine the influence of different impact conditions on the distribution of brain strain for ice hockey goaltender impacts. An instrumented headform was fitted with an ice hockey goaltender mask and impacted under a protocol which was developed using video analysis of real world ice hockey goaltender concussions for three different impact events (collision, puck, and fall). The resulting kinematic response served as input into the University College Dublin Brain Trauma Model (UCDBTM), which calculated maximum principal strain (MPS) in the cerebrum. Strain subsets were then determined and analyzed. Resulting peak strains (0.124–0.328) were found to be within the range for concussion reported in the literature. The results demonstrated that falls and collisions produced larger strain subsets in the cerebrum than puck impacts which is likely a reflection of longer impact duration for falls and collisions than puck impacts. For each impact event, impact site was also found to produce strain subsets of varying size and configuration. The results of this study suggest that the location and number of brain regions which can be damaged depend on the loading conditions of the impact.

Composite Solutions for Deck Catamarans

2018 ◽  
Vol 55 (1) ◽  
pp. 1-4
Author(s):  
Elena Felicia Beznea ◽  
Ionel Chirica ◽  
Adrian Presura ◽  
Ionel Iacob
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Sandwich Structure ◽  
High Strength ◽  
Total Weight ◽  
External Loading ◽  
Strength Analysis ◽  
Allowable Stress ◽  
The Finite Element Method ◽  
Inland Navigation

The paper is treating the strength analysis of the main deck structure of an inland navigation catamaran for 30 passengers. The main deck should have high stiffness and high strength to resist to external loading and endure high stresses from combined bending and torsion loads. Different materials for sandwich structure of the deck have been analysed by using the Finite Element Method in order to determine the solution which accomplish better designing criteria regarding allowable stress and deformations and total weight.

Design of Pipeline Composite Repairs: From Lab Scale Tests to FEA and Full Scale Testing

2014 ◽  
Author(s):  
Remy Her ◽  
Jacques Renard ◽  
Vincent Gaffard ◽  
Yves Favry ◽  
Paul Wiet
Keyword(s):  
Finite Element ◽  
Full Scale ◽  
Combined Loading ◽  
Material Strength ◽  
Repair System ◽  
Loading Conditions ◽  
Original Design ◽  
Composite Repair ◽  
Repair Systems ◽  
Composite Properties

Composite repair systems are used for many years to restore locally the pipe strength where it has been affected by damage such as wall thickness reduction due to corrosion, dent, lamination or cracks. Composite repair systems are commonly qualified, designed and installed according to ASME PCC2 code or ISO 24817 standard requirements. In both of these codes, the Maximum Allowable Working Pressure (MAWP) of the damaged section must be determined to design the composite repair. To do so, codes such as ASME B31G for example for corrosion, are used. The composite repair systems is designed to “bridge the gap” between the MAWP of the damaged pipe and the original design pressure. The main weakness of available approaches is their applicability to combined loading conditions and various types of defects. The objective of this work is to set-up a “universal” methodology to design the composite repair by finite element calculations with directly taking into consideration the loading conditions and the influence of the defect on pipe strength (whatever its geometry and type). First a program of mechanical tests is defined to allow determining all the composite properties necessary to run the finite elements calculations. It consists in compression and tensile tests in various directions to account for the composite anisotropy and of Arcan tests to determine steel to composite interface behaviors in tension and shear. In parallel, a full scale burst test is performed on a repaired pipe section where a local wall thinning is previously machined. For this test, the composite repair was designed according to ISO 24817. Then, a finite element model integrating damaged pipe and composite repair system is built. It allowed simulating the test, comparing the results with experiments and validating damage models implemented to capture the various possible types of failures. In addition, sensitivity analysis considering composite properties variations evidenced by experiments are run. The composite behavior considered in this study is not time dependent. No degradation of the composite material strength due to ageing is taking into account. The roadmap for the next steps of this work is to clearly identify the ageing mechanisms, to perform tests in relevant conditions and to introduce ageing effects in the design process (and in particular in the composite constitutive laws).

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