Gilchrist, I; Moglo, K; Storr, M; Pelland, L
Effects of head flexion posture on the multidirectional static force capacity of the neck Journal Article
In: Clinical Biomechanics, vol. 37, pp. 44–52, 2016.
Abstract | Links | BibTeX | Tags: adult, Article, Biomechanics, BIOPHYSICS, body equilibrium, body posture, Cervical spine, Concussions, contact sport, cross-sectional study, Dynamometry, force, head flexion, head movement, head position, human, human experiment, Male, Muscle, muscle contraction, muscle strength, neck injury, Neck muscle, neck strength, priority journal
@article{Gilchrist2016,
title = {Effects of head flexion posture on the multidirectional static force capacity of the neck},
author = {Gilchrist, I and Moglo, K and Storr, M and Pelland, L},
doi = {10.1016/j.clinbiomech.2016.05.016},
year = {2016},
date = {2016-01-01},
journal = {Clinical Biomechanics},
volume = {37},
pages = {44--52},
abstract = {Background Neck muscle force protects vertebral alignment and resists potentially injurious loading of osteoligamentous structures during head impacts. As the majority of neck muscles generate moments about all three planes of motion, it is not clear how the force capacity of the neck might be modulated by direction of force application and head posture. The aim of our study was to measure the multidirectional moment-generating capacity of the neck and to evaluate effects of 20° of head flexion, a common head position in contact sports, on the measured capacity. Methods We conducted a cross-sectional study, with 25 males, 20-30 years old, performing maximum voluntary contractions, with ballistic intent, along eight directions, set at 45° intervals in the horizontal plane of the head. Three-dimensional moments at C3 and T1 were calculated using equations of static equilibrium. The variable of interest was the impulse of force generated from 0-50 ms. Effects of direction of force application and head posture, neutral and 20° flexion, were evaluated by two-way analysis of variance and linear regression. Findings Impulse of force was lower along diagonal planes, at 45° from the mid-sagittal plane, compared to orthogonal planes (P \< 0.001). Compared to neutral posture, head flexion produced a 55.2% decrease in impulse capacity at C3 and 45.9% at T1. Interpretation The risk of injury with head impact would intrinsically be higher along diagonal planes and with a 20° head down position due to a lower moment generating capacity of the neck in the first 50 ms of force application. © 2015 Elsevier Ltd. All rights reserved.},
keywords = {adult, Article, Biomechanics, BIOPHYSICS, body equilibrium, body posture, Cervical spine, Concussions, contact sport, cross-sectional study, Dynamometry, force, head flexion, head movement, head position, human, human experiment, Male, Muscle, muscle contraction, muscle strength, neck injury, Neck muscle, neck strength, priority journal},
pubstate = {published},
tppubtype = {article}
}
Kawata, K; Rubin, L H; Lee, J H; Sim, T; Takahagi, M; Szwanki, V; Bellamy, A; Darvish, K; Assari, S; Henderer, J D; Tierney, R; Langford, D
Association of football subconcussive head impacts with ocular near point of convergence Journal Article
In: JAMA Ophthalmology, vol. 134, no. 7, pp. 763–769, 2016.
Abstract | Links | BibTeX | Tags: Acceleration, accelerometer, adult, Article, binocular convergence, Concussion, eye movement, follow up, football, head movement, human, KINEMATICS, major clinical study, Male, mouth protector, observational study, priority journal, prospective study, traumatic brain injury, Young Adult
@article{Kawata2016,
title = {Association of football subconcussive head impacts with ocular near point of convergence},
author = {Kawata, K and Rubin, L H and Lee, J H and Sim, T and Takahagi, M and Szwanki, V and Bellamy, A and Darvish, K and Assari, S and Henderer, J D and Tierney, R and Langford, D},
doi = {10.1001/jamaophthalmol.2016.1085},
year = {2016},
date = {2016-01-01},
journal = {JAMA Ophthalmology},
volume = {134},
number = {7},
pages = {763--769},
abstract = {IMPORTANCE An increased understanding of the relationship between subconcussive head impacts and near point of convergence (NPC) ocular-motor function may be useful in delineating traumatic brain injury. OBJECTIVE To investigate whether repetitive subconcussive head impacts during preseason football practice cause changes in NPC. DESIGN, SETTING, AND PARTICIPANTS This prospective, observational study of 29 National Collegiate Athletic Association Division I football players included baseline and preseason practices (1 noncontact and 4 contact), and postseason follow-up and outcome measures were obtained for each time. An accelerometer-embedded mouthguard measured head impact kinematics. Based on the sum of head impacts from all 5 practices, players were categorized into lower (n = 7) or higher (n = 22) impact groups. EXPOSURES Players participated in regular practices, and all head impacts greater than 10g from the 5 practices were recorded using the i1Biometerics Vector mouthguard (i1 Biometrics Inc). MAIN OUTCOMES AND MEASURES Near point of convergence measures and symptom scores. RESULTS A total of 1193 head impacts were recorded from 5 training camp practices in the 29 collegiate football players; 22 were categorized into the higher-impact group and 7 into the lower-impact group. Therewere significant differences in head impact kinematics between lower- and higher-impact groups (number of impacts, 6 vs 41 [lower impact minus higher impact = 35; 95%CI, 21-51; P \< .001]; linear acceleration, 99g vs 1112g [lower impact minus higher impact= 1013; 95%CI, 621 - 1578; P \< .001]; angular acceleration, 7589 radian/s2 vs 65016 radian/s2 [lower impact minus higher impact= 57 427; 95%CI , 31 123-80 498; P \< .001], respectively). The trajectory and cumulative burden of subconcussive impacts on NPC differed by group (F for group × linear trend1},
keywords = {Acceleration, accelerometer, adult, Article, binocular convergence, Concussion, eye movement, follow up, football, head movement, human, KINEMATICS, major clinical study, Male, mouth protector, observational study, priority journal, prospective study, traumatic brain injury, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Gilchrist, I; Moglo, K; Storr, M; Pelland, L
Effects of head flexion posture on the multidirectional static force capacity of the neck Journal Article
In: Clinical Biomechanics, vol. 37, pp. 44–52, 2016.
@article{Gilchrist2016,
title = {Effects of head flexion posture on the multidirectional static force capacity of the neck},
author = {Gilchrist, I and Moglo, K and Storr, M and Pelland, L},
doi = {10.1016/j.clinbiomech.2016.05.016},
year = {2016},
date = {2016-01-01},
journal = {Clinical Biomechanics},
volume = {37},
pages = {44--52},
abstract = {Background Neck muscle force protects vertebral alignment and resists potentially injurious loading of osteoligamentous structures during head impacts. As the majority of neck muscles generate moments about all three planes of motion, it is not clear how the force capacity of the neck might be modulated by direction of force application and head posture. The aim of our study was to measure the multidirectional moment-generating capacity of the neck and to evaluate effects of 20° of head flexion, a common head position in contact sports, on the measured capacity. Methods We conducted a cross-sectional study, with 25 males, 20-30 years old, performing maximum voluntary contractions, with ballistic intent, along eight directions, set at 45° intervals in the horizontal plane of the head. Three-dimensional moments at C3 and T1 were calculated using equations of static equilibrium. The variable of interest was the impulse of force generated from 0-50 ms. Effects of direction of force application and head posture, neutral and 20° flexion, were evaluated by two-way analysis of variance and linear regression. Findings Impulse of force was lower along diagonal planes, at 45° from the mid-sagittal plane, compared to orthogonal planes (P \< 0.001). Compared to neutral posture, head flexion produced a 55.2% decrease in impulse capacity at C3 and 45.9% at T1. Interpretation The risk of injury with head impact would intrinsically be higher along diagonal planes and with a 20° head down position due to a lower moment generating capacity of the neck in the first 50 ms of force application. © 2015 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Kawata, K; Rubin, L H; Lee, J H; Sim, T; Takahagi, M; Szwanki, V; Bellamy, A; Darvish, K; Assari, S; Henderer, J D; Tierney, R; Langford, D
Association of football subconcussive head impacts with ocular near point of convergence Journal Article
In: JAMA Ophthalmology, vol. 134, no. 7, pp. 763–769, 2016.
@article{Kawata2016,
title = {Association of football subconcussive head impacts with ocular near point of convergence},
author = {Kawata, K and Rubin, L H and Lee, J H and Sim, T and Takahagi, M and Szwanki, V and Bellamy, A and Darvish, K and Assari, S and Henderer, J D and Tierney, R and Langford, D},
doi = {10.1001/jamaophthalmol.2016.1085},
year = {2016},
date = {2016-01-01},
journal = {JAMA Ophthalmology},
volume = {134},
number = {7},
pages = {763--769},
abstract = {IMPORTANCE An increased understanding of the relationship between subconcussive head impacts and near point of convergence (NPC) ocular-motor function may be useful in delineating traumatic brain injury. OBJECTIVE To investigate whether repetitive subconcussive head impacts during preseason football practice cause changes in NPC. DESIGN, SETTING, AND PARTICIPANTS This prospective, observational study of 29 National Collegiate Athletic Association Division I football players included baseline and preseason practices (1 noncontact and 4 contact), and postseason follow-up and outcome measures were obtained for each time. An accelerometer-embedded mouthguard measured head impact kinematics. Based on the sum of head impacts from all 5 practices, players were categorized into lower (n = 7) or higher (n = 22) impact groups. EXPOSURES Players participated in regular practices, and all head impacts greater than 10g from the 5 practices were recorded using the i1Biometerics Vector mouthguard (i1 Biometrics Inc). MAIN OUTCOMES AND MEASURES Near point of convergence measures and symptom scores. RESULTS A total of 1193 head impacts were recorded from 5 training camp practices in the 29 collegiate football players; 22 were categorized into the higher-impact group and 7 into the lower-impact group. Therewere significant differences in head impact kinematics between lower- and higher-impact groups (number of impacts, 6 vs 41 [lower impact minus higher impact = 35; 95%CI, 21-51; P \< .001]; linear acceleration, 99g vs 1112g [lower impact minus higher impact= 1013; 95%CI, 621 - 1578; P \< .001]; angular acceleration, 7589 radian/s2 vs 65016 radian/s2 [lower impact minus higher impact= 57 427; 95%CI , 31 123-80 498; P \< .001], respectively). The trajectory and cumulative burden of subconcussive impacts on NPC differed by group (F for group × linear trend1},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gilchrist, I; Moglo, K; Storr, M; Pelland, L
Effects of head flexion posture on the multidirectional static force capacity of the neck Journal Article
In: Clinical Biomechanics, vol. 37, pp. 44–52, 2016.
Abstract | Links | BibTeX | Tags: adult, Article, Biomechanics, BIOPHYSICS, body equilibrium, body posture, Cervical spine, Concussions, contact sport, cross-sectional study, Dynamometry, force, head flexion, head movement, head position, human, human experiment, Male, Muscle, muscle contraction, muscle strength, neck injury, Neck muscle, neck strength, priority journal
@article{Gilchrist2016,
title = {Effects of head flexion posture on the multidirectional static force capacity of the neck},
author = {Gilchrist, I and Moglo, K and Storr, M and Pelland, L},
doi = {10.1016/j.clinbiomech.2016.05.016},
year = {2016},
date = {2016-01-01},
journal = {Clinical Biomechanics},
volume = {37},
pages = {44--52},
abstract = {Background Neck muscle force protects vertebral alignment and resists potentially injurious loading of osteoligamentous structures during head impacts. As the majority of neck muscles generate moments about all three planes of motion, it is not clear how the force capacity of the neck might be modulated by direction of force application and head posture. The aim of our study was to measure the multidirectional moment-generating capacity of the neck and to evaluate effects of 20° of head flexion, a common head position in contact sports, on the measured capacity. Methods We conducted a cross-sectional study, with 25 males, 20-30 years old, performing maximum voluntary contractions, with ballistic intent, along eight directions, set at 45° intervals in the horizontal plane of the head. Three-dimensional moments at C3 and T1 were calculated using equations of static equilibrium. The variable of interest was the impulse of force generated from 0-50 ms. Effects of direction of force application and head posture, neutral and 20° flexion, were evaluated by two-way analysis of variance and linear regression. Findings Impulse of force was lower along diagonal planes, at 45° from the mid-sagittal plane, compared to orthogonal planes (P \< 0.001). Compared to neutral posture, head flexion produced a 55.2% decrease in impulse capacity at C3 and 45.9% at T1. Interpretation The risk of injury with head impact would intrinsically be higher along diagonal planes and with a 20° head down position due to a lower moment generating capacity of the neck in the first 50 ms of force application. © 2015 Elsevier Ltd. All rights reserved.},
keywords = {adult, Article, Biomechanics, BIOPHYSICS, body equilibrium, body posture, Cervical spine, Concussions, contact sport, cross-sectional study, Dynamometry, force, head flexion, head movement, head position, human, human experiment, Male, Muscle, muscle contraction, muscle strength, neck injury, Neck muscle, neck strength, priority journal},
pubstate = {published},
tppubtype = {article}
}
Kawata, K; Rubin, L H; Lee, J H; Sim, T; Takahagi, M; Szwanki, V; Bellamy, A; Darvish, K; Assari, S; Henderer, J D; Tierney, R; Langford, D
Association of football subconcussive head impacts with ocular near point of convergence Journal Article
In: JAMA Ophthalmology, vol. 134, no. 7, pp. 763–769, 2016.
Abstract | Links | BibTeX | Tags: Acceleration, accelerometer, adult, Article, binocular convergence, Concussion, eye movement, follow up, football, head movement, human, KINEMATICS, major clinical study, Male, mouth protector, observational study, priority journal, prospective study, traumatic brain injury, Young Adult
@article{Kawata2016,
title = {Association of football subconcussive head impacts with ocular near point of convergence},
author = {Kawata, K and Rubin, L H and Lee, J H and Sim, T and Takahagi, M and Szwanki, V and Bellamy, A and Darvish, K and Assari, S and Henderer, J D and Tierney, R and Langford, D},
doi = {10.1001/jamaophthalmol.2016.1085},
year = {2016},
date = {2016-01-01},
journal = {JAMA Ophthalmology},
volume = {134},
number = {7},
pages = {763--769},
abstract = {IMPORTANCE An increased understanding of the relationship between subconcussive head impacts and near point of convergence (NPC) ocular-motor function may be useful in delineating traumatic brain injury. OBJECTIVE To investigate whether repetitive subconcussive head impacts during preseason football practice cause changes in NPC. DESIGN, SETTING, AND PARTICIPANTS This prospective, observational study of 29 National Collegiate Athletic Association Division I football players included baseline and preseason practices (1 noncontact and 4 contact), and postseason follow-up and outcome measures were obtained for each time. An accelerometer-embedded mouthguard measured head impact kinematics. Based on the sum of head impacts from all 5 practices, players were categorized into lower (n = 7) or higher (n = 22) impact groups. EXPOSURES Players participated in regular practices, and all head impacts greater than 10g from the 5 practices were recorded using the i1Biometerics Vector mouthguard (i1 Biometrics Inc). MAIN OUTCOMES AND MEASURES Near point of convergence measures and symptom scores. RESULTS A total of 1193 head impacts were recorded from 5 training camp practices in the 29 collegiate football players; 22 were categorized into the higher-impact group and 7 into the lower-impact group. Therewere significant differences in head impact kinematics between lower- and higher-impact groups (number of impacts, 6 vs 41 [lower impact minus higher impact = 35; 95%CI, 21-51; P \< .001]; linear acceleration, 99g vs 1112g [lower impact minus higher impact= 1013; 95%CI, 621 - 1578; P \< .001]; angular acceleration, 7589 radian/s2 vs 65016 radian/s2 [lower impact minus higher impact= 57 427; 95%CI , 31 123-80 498; P \< .001], respectively). The trajectory and cumulative burden of subconcussive impacts on NPC differed by group (F for group × linear trend1},
keywords = {Acceleration, accelerometer, adult, Article, binocular convergence, Concussion, eye movement, follow up, football, head movement, human, KINEMATICS, major clinical study, Male, mouth protector, observational study, priority journal, prospective study, traumatic brain injury, Young Adult},
pubstate = {published},
tppubtype = {article}
}