Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
Abstract | BibTeX | Tags: *HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {*HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY},
pubstate = {published},
tppubtype = {article}
}
Caryn, R C; Hazell, T J; Dickey, J P
Transmission of acceleration from a synchronous vibration exercise platform to the head Journal Article
In: International Journal of Sports Medicine, vol. 35, no. 4, pp. 330–338, 2014.
Abstract | BibTeX | Tags: *Exercise/ph [Physiology], *HEAD, *Knee Joint/ph [Physiology], *Posture/ph [Physiology], *Sports Equipment, *Vibration, Acceleration, adult, Humans, Male
@article{Caryn2014,
title = {Transmission of acceleration from a synchronous vibration exercise platform to the head},
author = {Caryn, R C and Hazell, T J and Dickey, J P},
year = {2014},
date = {2014-01-01},
journal = {International Journal of Sports Medicine},
volume = {35},
number = {4},
pages = {330--338},
abstract = {Exercise vibration platforms are becoming commonplace in homes and fitness centers. However, excessive mechanical energy transferred to the head and eye can cause injury. The purpose of this study was to evaluate how changes in platform frequency and knee flexion angle affect acceleration transmission to the head. Participants (N=12) stood on a whole-body vibration platform with knee flexion angles of 0degree, 20degree, and 40degree to evaluate how changes in knee flexion affected head acceleration. 7 specific platform frequencies were tested between 20-50Hz at 2 peak-to-peak displacement settings (1 and 2mm nominal). Accelerations were measured with triaxial accelerometers at the platform and head to generate transmissibility ratios. Platform-to-head transmissibility was not significantly different between the 2 platform peak-to-peak amplitudes (P\>0.05). Transmissibility measures varied depending on platform frequency and knee angle (P\<0.05). Flexing the knees resulted in reduced head transmissibility at all frequencies (P\<0.05). Platform-to-head transmissibility values exceeded 1.0 at both 20 and 25Hz platform vibration frequencies with the knees in full extension. To reduce the risk of injury to structures of the head during vibration exercise, using platforms frequencies below 30Hz with small knee flexion angles (\<40degree) should be avoided. Copyright © Georg Thieme Verlag KG Stuttgart . New York.},
keywords = {*Exercise/ph [Physiology], *HEAD, *Knee Joint/ph [Physiology], *Posture/ph [Physiology], *Sports Equipment, *Vibration, Acceleration, adult, Humans, Male},
pubstate = {published},
tppubtype = {article}
}
Estevan, I; Alvarez, O; Falco, C; Molina-Garcia, J; Castillo, I
Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo Journal Article
In: Journal of Strength & Conditioning Research, vol. 25, no. 10, pp. 2851–2856, 2011.
Abstract | BibTeX | Tags: *HEAD, *Martial Arts/ph [Physiology], *Task Performance and Analysis, adult, Biomechanical Phenomena, Humans, Male, Young Adult
@article{Estevan2011,
title = {Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo},
author = {Estevan, I and Alvarez, O and Falco, C and Molina-Garcia, J and Castillo, I},
year = {2011},
date = {2011-01-01},
journal = {Journal of Strength \& Conditioning Research},
volume = {25},
number = {10},
pages = {2851--2856},
abstract = {The execution distance is a tactic factor that affects mechanical performance and execution technique in taekwondo. This study analyzes the roundhouse kick to the head by comparing the maximum impact force, execution time, and impact time in 3 distances according to the athletes' competition level. It also analyzes the relationship between impact force and weight in each group. It examines whether the execution distance affects the maximum impact force, execution time, and impact time, in each level group or 2 different competition levels. Participants were 27 male taekwondo players (13 medallists and 14 nonmedallists). The medallists executed the roundhouse kick to the head with greater impact force and in a shorter execution time than did the nonmedallists when they kicked from any distance different to their combat distance. However, the results showed that the execution distance is influential in the execution time and impact time in the nonmedallist group. It is considered appropriate to orientate the high-level competitors to train for offensive actions from any distance similar to the long execution distance because it offers equally effectiveness and a greater security against the opponent. Also, practitioners should focus their training to improve time performance because it is more affected by distance than impact force.},
keywords = {*HEAD, *Martial Arts/ph [Physiology], *Task Performance and Analysis, adult, Biomechanical Phenomena, Humans, Male, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Hugenholtz, H; Richard, M T
On-site management of athletes with head injuries Journal Article
In: Physician & Sportsmedicine, vol. 11, no. 6, pp. 71, 1983, ISBN: 00913847.
BibTeX | Tags: *BRAIN -- Concussion, *DIAGNOSIS, *HEAD, *HEMODYNAMICS, *PERIODIC health examinations, *RESPIRATION, *THERAPEUTICS, *WOUNDS & injuries, Assessment & Testing, Treatment & Rehabilitation
@article{Hugenholtz1983,
title = {On-site management of athletes with head injuries},
author = {Hugenholtz, H and Richard, M T},
isbn = {00913847},
year = {1983},
date = {1983-01-01},
journal = {Physician \& Sportsmedicine},
volume = {11},
number = {6},
pages = {71},
keywords = {*BRAIN -- Concussion, *DIAGNOSIS, *HEAD, *HEMODYNAMICS, *PERIODIC health examinations, *RESPIRATION, *THERAPEUTICS, *WOUNDS \& injuries, Assessment \& Testing, Treatment \& Rehabilitation},
pubstate = {published},
tppubtype = {article}
}
Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Caryn, R C; Hazell, T J; Dickey, J P
Transmission of acceleration from a synchronous vibration exercise platform to the head Journal Article
In: International Journal of Sports Medicine, vol. 35, no. 4, pp. 330–338, 2014.
@article{Caryn2014,
title = {Transmission of acceleration from a synchronous vibration exercise platform to the head},
author = {Caryn, R C and Hazell, T J and Dickey, J P},
year = {2014},
date = {2014-01-01},
journal = {International Journal of Sports Medicine},
volume = {35},
number = {4},
pages = {330--338},
abstract = {Exercise vibration platforms are becoming commonplace in homes and fitness centers. However, excessive mechanical energy transferred to the head and eye can cause injury. The purpose of this study was to evaluate how changes in platform frequency and knee flexion angle affect acceleration transmission to the head. Participants (N=12) stood on a whole-body vibration platform with knee flexion angles of 0degree, 20degree, and 40degree to evaluate how changes in knee flexion affected head acceleration. 7 specific platform frequencies were tested between 20-50Hz at 2 peak-to-peak displacement settings (1 and 2mm nominal). Accelerations were measured with triaxial accelerometers at the platform and head to generate transmissibility ratios. Platform-to-head transmissibility was not significantly different between the 2 platform peak-to-peak amplitudes (P\>0.05). Transmissibility measures varied depending on platform frequency and knee angle (P\<0.05). Flexing the knees resulted in reduced head transmissibility at all frequencies (P\<0.05). Platform-to-head transmissibility values exceeded 1.0 at both 20 and 25Hz platform vibration frequencies with the knees in full extension. To reduce the risk of injury to structures of the head during vibration exercise, using platforms frequencies below 30Hz with small knee flexion angles (\<40degree) should be avoided. Copyright © Georg Thieme Verlag KG Stuttgart . New York.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Estevan, I; Alvarez, O; Falco, C; Molina-Garcia, J; Castillo, I
Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo Journal Article
In: Journal of Strength & Conditioning Research, vol. 25, no. 10, pp. 2851–2856, 2011.
@article{Estevan2011,
title = {Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo},
author = {Estevan, I and Alvarez, O and Falco, C and Molina-Garcia, J and Castillo, I},
year = {2011},
date = {2011-01-01},
journal = {Journal of Strength \& Conditioning Research},
volume = {25},
number = {10},
pages = {2851--2856},
abstract = {The execution distance is a tactic factor that affects mechanical performance and execution technique in taekwondo. This study analyzes the roundhouse kick to the head by comparing the maximum impact force, execution time, and impact time in 3 distances according to the athletes' competition level. It also analyzes the relationship between impact force and weight in each group. It examines whether the execution distance affects the maximum impact force, execution time, and impact time, in each level group or 2 different competition levels. Participants were 27 male taekwondo players (13 medallists and 14 nonmedallists). The medallists executed the roundhouse kick to the head with greater impact force and in a shorter execution time than did the nonmedallists when they kicked from any distance different to their combat distance. However, the results showed that the execution distance is influential in the execution time and impact time in the nonmedallist group. It is considered appropriate to orientate the high-level competitors to train for offensive actions from any distance similar to the long execution distance because it offers equally effectiveness and a greater security against the opponent. Also, practitioners should focus their training to improve time performance because it is more affected by distance than impact force.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hugenholtz, H; Richard, M T
On-site management of athletes with head injuries Journal Article
In: Physician & Sportsmedicine, vol. 11, no. 6, pp. 71, 1983, ISBN: 00913847.
@article{Hugenholtz1983,
title = {On-site management of athletes with head injuries},
author = {Hugenholtz, H and Richard, M T},
isbn = {00913847},
year = {1983},
date = {1983-01-01},
journal = {Physician \& Sportsmedicine},
volume = {11},
number = {6},
pages = {71},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Hernandez, F; Shull, P B; Camarillo, D B
Evaluation of a laboratory model of human head impact biomechanics Journal Article
In: Journal of Biomechanics, vol. 48, no. 12, pp. 3469–3477, 2015.
Abstract | BibTeX | Tags: *HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY
@article{Hernandez2015,
title = {Evaluation of a laboratory model of human head impact biomechanics},
author = {Hernandez, F and Shull, P B and Camarillo, D B},
year = {2015},
date = {2015-01-01},
journal = {Journal of Biomechanics},
volume = {48},
number = {12},
pages = {3469--3477},
abstract = {This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests ($sim$100 Hz) than field impacts ($sim$10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.},
keywords = {*HEAD, *Laboratories, *Mechanical Phenomena, *Models, Acceleration, Biological, Biomechanical Phenomena, Brain Concussion/et [Etiology], Football/in [Injuries], Head Protective Devices, Humans, Male, Neck/ph [Physiology], Rotation, SAFETY},
pubstate = {published},
tppubtype = {article}
}
Caryn, R C; Hazell, T J; Dickey, J P
Transmission of acceleration from a synchronous vibration exercise platform to the head Journal Article
In: International Journal of Sports Medicine, vol. 35, no. 4, pp. 330–338, 2014.
Abstract | BibTeX | Tags: *Exercise/ph [Physiology], *HEAD, *Knee Joint/ph [Physiology], *Posture/ph [Physiology], *Sports Equipment, *Vibration, Acceleration, adult, Humans, Male
@article{Caryn2014,
title = {Transmission of acceleration from a synchronous vibration exercise platform to the head},
author = {Caryn, R C and Hazell, T J and Dickey, J P},
year = {2014},
date = {2014-01-01},
journal = {International Journal of Sports Medicine},
volume = {35},
number = {4},
pages = {330--338},
abstract = {Exercise vibration platforms are becoming commonplace in homes and fitness centers. However, excessive mechanical energy transferred to the head and eye can cause injury. The purpose of this study was to evaluate how changes in platform frequency and knee flexion angle affect acceleration transmission to the head. Participants (N=12) stood on a whole-body vibration platform with knee flexion angles of 0degree, 20degree, and 40degree to evaluate how changes in knee flexion affected head acceleration. 7 specific platform frequencies were tested between 20-50Hz at 2 peak-to-peak displacement settings (1 and 2mm nominal). Accelerations were measured with triaxial accelerometers at the platform and head to generate transmissibility ratios. Platform-to-head transmissibility was not significantly different between the 2 platform peak-to-peak amplitudes (P\>0.05). Transmissibility measures varied depending on platform frequency and knee angle (P\<0.05). Flexing the knees resulted in reduced head transmissibility at all frequencies (P\<0.05). Platform-to-head transmissibility values exceeded 1.0 at both 20 and 25Hz platform vibration frequencies with the knees in full extension. To reduce the risk of injury to structures of the head during vibration exercise, using platforms frequencies below 30Hz with small knee flexion angles (\<40degree) should be avoided. Copyright © Georg Thieme Verlag KG Stuttgart . New York.},
keywords = {*Exercise/ph [Physiology], *HEAD, *Knee Joint/ph [Physiology], *Posture/ph [Physiology], *Sports Equipment, *Vibration, Acceleration, adult, Humans, Male},
pubstate = {published},
tppubtype = {article}
}
Estevan, I; Alvarez, O; Falco, C; Molina-Garcia, J; Castillo, I
Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo Journal Article
In: Journal of Strength & Conditioning Research, vol. 25, no. 10, pp. 2851–2856, 2011.
Abstract | BibTeX | Tags: *HEAD, *Martial Arts/ph [Physiology], *Task Performance and Analysis, adult, Biomechanical Phenomena, Humans, Male, Young Adult
@article{Estevan2011,
title = {Impact force and time analysis influenced by execution distance in a roundhouse kick to the head in taekwondo},
author = {Estevan, I and Alvarez, O and Falco, C and Molina-Garcia, J and Castillo, I},
year = {2011},
date = {2011-01-01},
journal = {Journal of Strength \& Conditioning Research},
volume = {25},
number = {10},
pages = {2851--2856},
abstract = {The execution distance is a tactic factor that affects mechanical performance and execution technique in taekwondo. This study analyzes the roundhouse kick to the head by comparing the maximum impact force, execution time, and impact time in 3 distances according to the athletes' competition level. It also analyzes the relationship between impact force and weight in each group. It examines whether the execution distance affects the maximum impact force, execution time, and impact time, in each level group or 2 different competition levels. Participants were 27 male taekwondo players (13 medallists and 14 nonmedallists). The medallists executed the roundhouse kick to the head with greater impact force and in a shorter execution time than did the nonmedallists when they kicked from any distance different to their combat distance. However, the results showed that the execution distance is influential in the execution time and impact time in the nonmedallist group. It is considered appropriate to orientate the high-level competitors to train for offensive actions from any distance similar to the long execution distance because it offers equally effectiveness and a greater security against the opponent. Also, practitioners should focus their training to improve time performance because it is more affected by distance than impact force.},
keywords = {*HEAD, *Martial Arts/ph [Physiology], *Task Performance and Analysis, adult, Biomechanical Phenomena, Humans, Male, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Hugenholtz, H; Richard, M T
On-site management of athletes with head injuries Journal Article
In: Physician & Sportsmedicine, vol. 11, no. 6, pp. 71, 1983, ISBN: 00913847.
BibTeX | Tags: *BRAIN -- Concussion, *DIAGNOSIS, *HEAD, *HEMODYNAMICS, *PERIODIC health examinations, *RESPIRATION, *THERAPEUTICS, *WOUNDS & injuries, Assessment & Testing, Treatment & Rehabilitation
@article{Hugenholtz1983,
title = {On-site management of athletes with head injuries},
author = {Hugenholtz, H and Richard, M T},
isbn = {00913847},
year = {1983},
date = {1983-01-01},
journal = {Physician \& Sportsmedicine},
volume = {11},
number = {6},
pages = {71},
keywords = {*BRAIN -- Concussion, *DIAGNOSIS, *HEAD, *HEMODYNAMICS, *PERIODIC health examinations, *RESPIRATION, *THERAPEUTICS, *WOUNDS \& injuries, Assessment \& Testing, Treatment \& Rehabilitation},
pubstate = {published},
tppubtype = {article}
}