Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
Abstract | BibTeX | Tags: *Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {*Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
schmidtj uga edu Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W
Head Impact Magnitude in American High School Football Journal Article
In: Pediatrics, vol. 138, no. 2, pp. 1–9, 2016, ISBN: 00314005.
Abstract | Links | BibTeX | Tags: ACCELERATION (Mechanics), Biomechanics, DATA analysis -- Software, Football injuries -- Prevention, Head injuries -- Prevention, HIGH school athletes, SAFETY hats, SAMPLING (Statistics), VIDEO recording
@article{Schmidt2016,
title = {Head Impact Magnitude in American High School Football},
author = {schmidtj uga edu Schmidt, Julianne D and Guskiewicz, Kevin M and Mihalik, Jason P and Blackburn, J Troy and Siegmund, Gunter P and Marshall, Stephen W},
doi = {10.1542/peds.2015-4231},
isbn = {00314005},
year = {2016},
date = {2016-01-01},
journal = {Pediatrics},
volume = {138},
number = {2},
pages = {1--9},
abstract = {OBJECTIVES: To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS: Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects ($alpha$ = 0.05). RESULTS: The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P= .03); contact with another player (linear, rotational, HITsp: P \< .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P \< .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P \< .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS: Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered. [ABSTRACT FROM AUTHOR]},
keywords = {ACCELERATION (Mechanics), Biomechanics, DATA analysis -- Software, Football injuries -- Prevention, Head injuries -- Prevention, HIGH school athletes, SAFETY hats, SAMPLING (Statistics), VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
Hutchison, M G; Comper, P; Meeuwisse, W H; Echemendia, R J
A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what? Journal Article
In: British Journal of Sports Medicine, vol. 49, no. 8, pp. 547–551, 2015.
Abstract | BibTeX | Tags: *Brain Concussion/ep [Epidemiology], *Hockey/in [Injuries], adult, Athletic Injuries/ep [Epidemiology], Athletic Injuries/et [Etiology], Body Height/ph [Physiology], Body Weight/ph [Physiology], Brain Concussion/et [Etiology], Canada/ep [Epidemiology], checklist, Head Protective Devices/sn [Statistics & Numerical, Hockey/sn [Statistics & Numerical Data], Humans, Male, Sports Equipment/sn [Statistics & Numerical Data], VIDEO recording, Young Adult
@article{Hutchison2015,
title = {A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what?},
author = {Hutchison, M G and Comper, P and Meeuwisse, W H and Echemendia, R J},
year = {2015},
date = {2015-01-01},
journal = {British Journal of Sports Medicine},
volume = {49},
number = {8},
pages = {547--551},
abstract = {BACKGROUND: Although there is a growing understanding of the consequences of concussions in hockey, very little is known about the precipitating factors associated with this type of injury. AIM: To describe player characteristics and situational factors associated with concussions in the National Hockey League (NHL). METHODS: Case series of medically diagnosed concussions for regular season games over a 3.5-year period during the 2006-2010 seasons using an inclusive cohort of professional hockey players. Digital video records were coded and analysed using the Heads Up Checklist. RESULTS: Of 197 medically diagnosed concussions, 88% involved contact with an opponent. Forwards accounted for more concussions than expected compared with on-ice proportional representation (95% CI 60 to 73; p=0.04). Significantly more concussions occurred in the first period (47%) compared with the second and third periods (p=0.047), with the majority of concussions occurring in the defensive zone (45%). Approximately 47% of the concussions occurred in open ice, 53% occurred in the perimeter. Finally, 37% of the concussions involved injured players' heads contacting the boards or glass. CONCLUSIONS: This study describes several specific factors associated with concussions in the NHL, including period of the game, player position, body size, and specific locations on the ice and particular situations based on a player's position.Copyright Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.},
keywords = {*Brain Concussion/ep [Epidemiology], *Hockey/in [Injuries], adult, Athletic Injuries/ep [Epidemiology], Athletic Injuries/et [Etiology], Body Height/ph [Physiology], Body Weight/ph [Physiology], Brain Concussion/et [Etiology], Canada/ep [Epidemiology], checklist, Head Protective Devices/sn [Statistics \& Numerical, Hockey/sn [Statistics \& Numerical Data], Humans, Male, Sports Equipment/sn [Statistics \& Numerical Data], VIDEO recording, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Fuller, C W; Jones, R; Fuller, A D
Defining a safe player run-off zone around rugby union playing areas Journal Article
In: Injury Prevention, vol. 21, no. 5, pp. 309–313, 2015.
Abstract | Links | BibTeX | Tags: Accident prevention, Athletic Injuries, brain concussion, Competitive Behavior, Environment Design, environmental planning, exercise, football, human, Humans, Incidence, Male, Physical Conditioning, physical education, Physical Education and Training, procedures, risk factor, Risk Factors, Sprains and Strains, VIDEO recording, videorecording
@article{Fuller2015ab,
title = {Defining a safe player run-off zone around rugby union playing areas},
author = {Fuller, C W and Jones, R and Fuller, A D},
doi = {10.1136/injuryprev-2015-041587},
year = {2015},
date = {2015-01-01},
journal = {Injury Prevention},
volume = {21},
number = {5},
pages = {309--313},
abstract = {Objectives To identify the circumstances in which international rugby players exit the playing area during match activities and to define a safe run-off distance around the playing area. Method An observational study using video recordings of 102 matches associated with the Rugby World Cup (2011), Rugby Championship (2013, 2014) and Six Nations Championship (2013, 2014) were used to analyse every event in which one or more players exited the playing area during normal match activities. The circumstances in which a player exited the playing area were categorised using a range of parameters: playing position, location, out-of-play region, match activity, distance travelled over the touchline, contacts made with pitchside fixtures and fittings. Results Ninety-five per cent of player-excursions took place within 5.2 m of the touchline. Players exiting the playing area were nearly three times more likely to be a back than a forward (p\<0.001) and the event was more likely to take place when a team was defending than attacking (p\<0.001). Being forced out of play during a contact event (70%) was the major reason for players exiting the playing area. Most players (88%) exiting the playing area only made contact with the perimeter area surface; a small proportion of players contacted touchline flags (6.1%), advertising boards (2.3%) and TV cameras/equipment (1.0%). Conclusions A minimum hazard-free distance of 5 m around a Rugby pitch is proposed based on the 95% percentile frequency distribution of player-excursion events into the areas contiguous with the playing area. © 2015 BMJ Publishing Group. All rights reserved.},
keywords = {Accident prevention, Athletic Injuries, brain concussion, Competitive Behavior, Environment Design, environmental planning, exercise, football, human, Humans, Incidence, Male, Physical Conditioning, physical education, Physical Education and Training, procedures, risk factor, Risk Factors, Sprains and Strains, VIDEO recording, videorecording},
pubstate = {published},
tppubtype = {article}
}
Ivancic, P C
Neck injury response to direct head impact Journal Article
In: Accident Analysis & Prevention, vol. 50, pp. 323–329, 2013.
Abstract | BibTeX | Tags: *Accidents, *Neck Injuries/et [Etiology], *Neck Injuries/pp [Physiopathology], Acceleration, ANALYSIS of variance, Biomechanical Phenomena, Cadaver, Humans, Manikins, Rotation, Traffic, VIDEO recording
@article{Ivancic2013,
title = {Neck injury response to direct head impact},
author = {Ivancic, P C},
year = {2013},
date = {2013-01-01},
journal = {Accident Analysis \& Prevention},
volume = {50},
pages = {323--329},
abstract = {Previous in vivo studies have observed flexion of the upper or upper/middle cervical spine and extension at inferior spinal levels due to direct head impacts. These studies hypothesized that hyperflexion may contribute to injury of the upper or middle cervical spine during real-life head impact. Our objectives were to determine the cervical spine injury response to direct head impact, document injuries, and compare our results with previously reported in vivo data. Our model consisted of a human cadaver neck (n=6) mounted to the torso of a rear impact dummy and carrying a surrogate head. Rearward force was applied to the model's forehead using a cable and pulley system and free-falling mass of 3.6kg followed by 16.7kg. High-speed digital cameras tracked head, vertebral, and pelvic motions. Average peak spinal rotations observed during impact were statistically compared (P\<0.05) to physiological ranges obtained from intact flexibility tests. Peak head impact force was 249 and 504N for the 3.6 and 16.7kg free-falling masses, respectively. Occipital condyle loads reached 205.3N posterior shear, 331.4N compression, and 7.4Nm extension moment. We observed significant increases in intervertebral extension peaks above physiologic at C6/7 (26.3degree vs. 5.7degree) and C7/T1 (29.7degree vs. 4.6degree) and macroscopic ligamentous and osseous injuries at C6 through T1 due to the 504N impacts. Our results indicate that a rearward head shear force causes complex neck loads of posterior shear, compression, and extension moment sufficient to injure the lower cervical spine. Real-life neck injuries due to motor vehicle crashes, sports impacts, or falls are likely due to combined loads transferred to the neck by direct head impact and torso inertial loads. Copyright © 2012 Elsevier Ltd. All rights reserved.},
keywords = {*Accidents, *Neck Injuries/et [Etiology], *Neck Injuries/pp [Physiopathology], Acceleration, ANALYSIS of variance, Biomechanical Phenomena, Cadaver, Humans, Manikins, Rotation, Traffic, VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
schmidtj uga edu Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W
Head Impact Magnitude in American High School Football Journal Article
In: Pediatrics, vol. 138, no. 2, pp. 1–9, 2016, ISBN: 00314005.
@article{Schmidt2016,
title = {Head Impact Magnitude in American High School Football},
author = {schmidtj uga edu Schmidt, Julianne D and Guskiewicz, Kevin M and Mihalik, Jason P and Blackburn, J Troy and Siegmund, Gunter P and Marshall, Stephen W},
doi = {10.1542/peds.2015-4231},
isbn = {00314005},
year = {2016},
date = {2016-01-01},
journal = {Pediatrics},
volume = {138},
number = {2},
pages = {1--9},
abstract = {OBJECTIVES: To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS: Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects ($alpha$ = 0.05). RESULTS: The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P= .03); contact with another player (linear, rotational, HITsp: P \< .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P \< .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P \< .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS: Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered. [ABSTRACT FROM AUTHOR]},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hutchison, M G; Comper, P; Meeuwisse, W H; Echemendia, R J
A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what? Journal Article
In: British Journal of Sports Medicine, vol. 49, no. 8, pp. 547–551, 2015.
@article{Hutchison2015,
title = {A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what?},
author = {Hutchison, M G and Comper, P and Meeuwisse, W H and Echemendia, R J},
year = {2015},
date = {2015-01-01},
journal = {British Journal of Sports Medicine},
volume = {49},
number = {8},
pages = {547--551},
abstract = {BACKGROUND: Although there is a growing understanding of the consequences of concussions in hockey, very little is known about the precipitating factors associated with this type of injury. AIM: To describe player characteristics and situational factors associated with concussions in the National Hockey League (NHL). METHODS: Case series of medically diagnosed concussions for regular season games over a 3.5-year period during the 2006-2010 seasons using an inclusive cohort of professional hockey players. Digital video records were coded and analysed using the Heads Up Checklist. RESULTS: Of 197 medically diagnosed concussions, 88% involved contact with an opponent. Forwards accounted for more concussions than expected compared with on-ice proportional representation (95% CI 60 to 73; p=0.04). Significantly more concussions occurred in the first period (47%) compared with the second and third periods (p=0.047), with the majority of concussions occurring in the defensive zone (45%). Approximately 47% of the concussions occurred in open ice, 53% occurred in the perimeter. Finally, 37% of the concussions involved injured players' heads contacting the boards or glass. CONCLUSIONS: This study describes several specific factors associated with concussions in the NHL, including period of the game, player position, body size, and specific locations on the ice and particular situations based on a player's position.Copyright Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fuller, C W; Jones, R; Fuller, A D
Defining a safe player run-off zone around rugby union playing areas Journal Article
In: Injury Prevention, vol. 21, no. 5, pp. 309–313, 2015.
@article{Fuller2015ab,
title = {Defining a safe player run-off zone around rugby union playing areas},
author = {Fuller, C W and Jones, R and Fuller, A D},
doi = {10.1136/injuryprev-2015-041587},
year = {2015},
date = {2015-01-01},
journal = {Injury Prevention},
volume = {21},
number = {5},
pages = {309--313},
abstract = {Objectives To identify the circumstances in which international rugby players exit the playing area during match activities and to define a safe run-off distance around the playing area. Method An observational study using video recordings of 102 matches associated with the Rugby World Cup (2011), Rugby Championship (2013, 2014) and Six Nations Championship (2013, 2014) were used to analyse every event in which one or more players exited the playing area during normal match activities. The circumstances in which a player exited the playing area were categorised using a range of parameters: playing position, location, out-of-play region, match activity, distance travelled over the touchline, contacts made with pitchside fixtures and fittings. Results Ninety-five per cent of player-excursions took place within 5.2 m of the touchline. Players exiting the playing area were nearly three times more likely to be a back than a forward (p\<0.001) and the event was more likely to take place when a team was defending than attacking (p\<0.001). Being forced out of play during a contact event (70%) was the major reason for players exiting the playing area. Most players (88%) exiting the playing area only made contact with the perimeter area surface; a small proportion of players contacted touchline flags (6.1%), advertising boards (2.3%) and TV cameras/equipment (1.0%). Conclusions A minimum hazard-free distance of 5 m around a Rugby pitch is proposed based on the 95% percentile frequency distribution of player-excursion events into the areas contiguous with the playing area. © 2015 BMJ Publishing Group. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Ivancic, P C
Neck injury response to direct head impact Journal Article
In: Accident Analysis & Prevention, vol. 50, pp. 323–329, 2013.
@article{Ivancic2013,
title = {Neck injury response to direct head impact},
author = {Ivancic, P C},
year = {2013},
date = {2013-01-01},
journal = {Accident Analysis \& Prevention},
volume = {50},
pages = {323--329},
abstract = {Previous in vivo studies have observed flexion of the upper or upper/middle cervical spine and extension at inferior spinal levels due to direct head impacts. These studies hypothesized that hyperflexion may contribute to injury of the upper or middle cervical spine during real-life head impact. Our objectives were to determine the cervical spine injury response to direct head impact, document injuries, and compare our results with previously reported in vivo data. Our model consisted of a human cadaver neck (n=6) mounted to the torso of a rear impact dummy and carrying a surrogate head. Rearward force was applied to the model's forehead using a cable and pulley system and free-falling mass of 3.6kg followed by 16.7kg. High-speed digital cameras tracked head, vertebral, and pelvic motions. Average peak spinal rotations observed during impact were statistically compared (P\<0.05) to physiological ranges obtained from intact flexibility tests. Peak head impact force was 249 and 504N for the 3.6 and 16.7kg free-falling masses, respectively. Occipital condyle loads reached 205.3N posterior shear, 331.4N compression, and 7.4Nm extension moment. We observed significant increases in intervertebral extension peaks above physiologic at C6/7 (26.3degree vs. 5.7degree) and C7/T1 (29.7degree vs. 4.6degree) and macroscopic ligamentous and osseous injuries at C6 through T1 due to the 504N impacts. Our results indicate that a rearward head shear force causes complex neck loads of posterior shear, compression, and extension moment sufficient to injure the lower cervical spine. Real-life neck injuries due to motor vehicle crashes, sports impacts, or falls are likely due to combined loads transferred to the neck by direct head impact and torso inertial loads. Copyright © 2012 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wu, L C; Nangia, V; Bui, K; Hammoor, B; Kurt, M; Hernandez, F; Kuo, C; Camarillo, D B
In Vivo Evaluation of Wearable Head Impact Sensors Journal Article
In: Annals of Biomedical Engineering, vol. 44, no. 4, pp. 1234–1245, 2016.
Abstract | BibTeX | Tags: *Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording
@article{Wu2016,
title = {In Vivo Evaluation of Wearable Head Impact Sensors},
author = {Wu, L C and Nangia, V and Bui, K and Hammoor, B and Kurt, M and Hernandez, F and Kuo, C and Camarillo, D B},
year = {2016},
date = {2016-01-01},
journal = {Annals of Biomedical Engineering},
volume = {44},
number = {4},
pages = {1234--1245},
abstract = {Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (\<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for alpha(mag)) and the skull cap (320% NRMS error for a(mag), 500% for alpha(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.},
keywords = {*Head Movements/ph [Physiology], *Models, *Soccer/ph [Physiology], *Telemetry/is [Instrumentation], adult, Biological, Biomechanical Phenomena, Craniocerebral Trauma, Humans, Male, MOUTH protectors, Skin, Soccer/in [Injuries], VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
schmidtj uga edu Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W
Head Impact Magnitude in American High School Football Journal Article
In: Pediatrics, vol. 138, no. 2, pp. 1–9, 2016, ISBN: 00314005.
Abstract | Links | BibTeX | Tags: ACCELERATION (Mechanics), Biomechanics, DATA analysis -- Software, Football injuries -- Prevention, Head injuries -- Prevention, HIGH school athletes, SAFETY hats, SAMPLING (Statistics), VIDEO recording
@article{Schmidt2016,
title = {Head Impact Magnitude in American High School Football},
author = {schmidtj uga edu Schmidt, Julianne D and Guskiewicz, Kevin M and Mihalik, Jason P and Blackburn, J Troy and Siegmund, Gunter P and Marshall, Stephen W},
doi = {10.1542/peds.2015-4231},
isbn = {00314005},
year = {2016},
date = {2016-01-01},
journal = {Pediatrics},
volume = {138},
number = {2},
pages = {1--9},
abstract = {OBJECTIVES: To describe determinants of head impact magnitudes between various play aspects in high school football. METHODS: Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects ($alpha$ = 0.05). RESULTS: The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P= .03); contact with another player (linear, rotational, HITsp: P \< .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P \< .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P \< .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). CONCLUSIONS: Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered. [ABSTRACT FROM AUTHOR]},
keywords = {ACCELERATION (Mechanics), Biomechanics, DATA analysis -- Software, Football injuries -- Prevention, Head injuries -- Prevention, HIGH school athletes, SAFETY hats, SAMPLING (Statistics), VIDEO recording},
pubstate = {published},
tppubtype = {article}
}
Hutchison, M G; Comper, P; Meeuwisse, W H; Echemendia, R J
A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what? Journal Article
In: British Journal of Sports Medicine, vol. 49, no. 8, pp. 547–551, 2015.
Abstract | BibTeX | Tags: *Brain Concussion/ep [Epidemiology], *Hockey/in [Injuries], adult, Athletic Injuries/ep [Epidemiology], Athletic Injuries/et [Etiology], Body Height/ph [Physiology], Body Weight/ph [Physiology], Brain Concussion/et [Etiology], Canada/ep [Epidemiology], checklist, Head Protective Devices/sn [Statistics & Numerical, Hockey/sn [Statistics & Numerical Data], Humans, Male, Sports Equipment/sn [Statistics & Numerical Data], VIDEO recording, Young Adult
@article{Hutchison2015,
title = {A systematic video analysis of National Hockey League (NHL) concussions, part I: who, when, where and what?},
author = {Hutchison, M G and Comper, P and Meeuwisse, W H and Echemendia, R J},
year = {2015},
date = {2015-01-01},
journal = {British Journal of Sports Medicine},
volume = {49},
number = {8},
pages = {547--551},
abstract = {BACKGROUND: Although there is a growing understanding of the consequences of concussions in hockey, very little is known about the precipitating factors associated with this type of injury. AIM: To describe player characteristics and situational factors associated with concussions in the National Hockey League (NHL). METHODS: Case series of medically diagnosed concussions for regular season games over a 3.5-year period during the 2006-2010 seasons using an inclusive cohort of professional hockey players. Digital video records were coded and analysed using the Heads Up Checklist. RESULTS: Of 197 medically diagnosed concussions, 88% involved contact with an opponent. Forwards accounted for more concussions than expected compared with on-ice proportional representation (95% CI 60 to 73; p=0.04). Significantly more concussions occurred in the first period (47%) compared with the second and third periods (p=0.047), with the majority of concussions occurring in the defensive zone (45%). Approximately 47% of the concussions occurred in open ice, 53% occurred in the perimeter. Finally, 37% of the concussions involved injured players' heads contacting the boards or glass. CONCLUSIONS: This study describes several specific factors associated with concussions in the NHL, including period of the game, player position, body size, and specific locations on the ice and particular situations based on a player's position.Copyright Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.},
keywords = {*Brain Concussion/ep [Epidemiology], *Hockey/in [Injuries], adult, Athletic Injuries/ep [Epidemiology], Athletic Injuries/et [Etiology], Body Height/ph [Physiology], Body Weight/ph [Physiology], Brain Concussion/et [Etiology], Canada/ep [Epidemiology], checklist, Head Protective Devices/sn [Statistics \& Numerical, Hockey/sn [Statistics \& Numerical Data], Humans, Male, Sports Equipment/sn [Statistics \& Numerical Data], VIDEO recording, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Fuller, C W; Jones, R; Fuller, A D
Defining a safe player run-off zone around rugby union playing areas Journal Article
In: Injury Prevention, vol. 21, no. 5, pp. 309–313, 2015.
Abstract | Links | BibTeX | Tags: Accident prevention, Athletic Injuries, brain concussion, Competitive Behavior, Environment Design, environmental planning, exercise, football, human, Humans, Incidence, Male, Physical Conditioning, physical education, Physical Education and Training, procedures, risk factor, Risk Factors, Sprains and Strains, VIDEO recording, videorecording
@article{Fuller2015ab,
title = {Defining a safe player run-off zone around rugby union playing areas},
author = {Fuller, C W and Jones, R and Fuller, A D},
doi = {10.1136/injuryprev-2015-041587},
year = {2015},
date = {2015-01-01},
journal = {Injury Prevention},
volume = {21},
number = {5},
pages = {309--313},
abstract = {Objectives To identify the circumstances in which international rugby players exit the playing area during match activities and to define a safe run-off distance around the playing area. Method An observational study using video recordings of 102 matches associated with the Rugby World Cup (2011), Rugby Championship (2013, 2014) and Six Nations Championship (2013, 2014) were used to analyse every event in which one or more players exited the playing area during normal match activities. The circumstances in which a player exited the playing area were categorised using a range of parameters: playing position, location, out-of-play region, match activity, distance travelled over the touchline, contacts made with pitchside fixtures and fittings. Results Ninety-five per cent of player-excursions took place within 5.2 m of the touchline. Players exiting the playing area were nearly three times more likely to be a back than a forward (p\<0.001) and the event was more likely to take place when a team was defending than attacking (p\<0.001). Being forced out of play during a contact event (70%) was the major reason for players exiting the playing area. Most players (88%) exiting the playing area only made contact with the perimeter area surface; a small proportion of players contacted touchline flags (6.1%), advertising boards (2.3%) and TV cameras/equipment (1.0%). Conclusions A minimum hazard-free distance of 5 m around a Rugby pitch is proposed based on the 95% percentile frequency distribution of player-excursion events into the areas contiguous with the playing area. © 2015 BMJ Publishing Group. All rights reserved.},
keywords = {Accident prevention, Athletic Injuries, brain concussion, Competitive Behavior, Environment Design, environmental planning, exercise, football, human, Humans, Incidence, Male, Physical Conditioning, physical education, Physical Education and Training, procedures, risk factor, Risk Factors, Sprains and Strains, VIDEO recording, videorecording},
pubstate = {published},
tppubtype = {article}
}
Ivancic, P C
Neck injury response to direct head impact Journal Article
In: Accident Analysis & Prevention, vol. 50, pp. 323–329, 2013.
Abstract | BibTeX | Tags: *Accidents, *Neck Injuries/et [Etiology], *Neck Injuries/pp [Physiopathology], Acceleration, ANALYSIS of variance, Biomechanical Phenomena, Cadaver, Humans, Manikins, Rotation, Traffic, VIDEO recording
@article{Ivancic2013,
title = {Neck injury response to direct head impact},
author = {Ivancic, P C},
year = {2013},
date = {2013-01-01},
journal = {Accident Analysis \& Prevention},
volume = {50},
pages = {323--329},
abstract = {Previous in vivo studies have observed flexion of the upper or upper/middle cervical spine and extension at inferior spinal levels due to direct head impacts. These studies hypothesized that hyperflexion may contribute to injury of the upper or middle cervical spine during real-life head impact. Our objectives were to determine the cervical spine injury response to direct head impact, document injuries, and compare our results with previously reported in vivo data. Our model consisted of a human cadaver neck (n=6) mounted to the torso of a rear impact dummy and carrying a surrogate head. Rearward force was applied to the model's forehead using a cable and pulley system and free-falling mass of 3.6kg followed by 16.7kg. High-speed digital cameras tracked head, vertebral, and pelvic motions. Average peak spinal rotations observed during impact were statistically compared (P\<0.05) to physiological ranges obtained from intact flexibility tests. Peak head impact force was 249 and 504N for the 3.6 and 16.7kg free-falling masses, respectively. Occipital condyle loads reached 205.3N posterior shear, 331.4N compression, and 7.4Nm extension moment. We observed significant increases in intervertebral extension peaks above physiologic at C6/7 (26.3degree vs. 5.7degree) and C7/T1 (29.7degree vs. 4.6degree) and macroscopic ligamentous and osseous injuries at C6 through T1 due to the 504N impacts. Our results indicate that a rearward head shear force causes complex neck loads of posterior shear, compression, and extension moment sufficient to injure the lower cervical spine. Real-life neck injuries due to motor vehicle crashes, sports impacts, or falls are likely due to combined loads transferred to the neck by direct head impact and torso inertial loads. Copyright © 2012 Elsevier Ltd. All rights reserved.},
keywords = {*Accidents, *Neck Injuries/et [Etiology], *Neck Injuries/pp [Physiopathology], Acceleration, ANALYSIS of variance, Biomechanical Phenomena, Cadaver, Humans, Manikins, Rotation, Traffic, VIDEO recording},
pubstate = {published},
tppubtype = {article}
}