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| 2. |
- Carlsson, Anna K, 1966, et al.
(author)
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Motion of the Head and Neck of Female and Male Volunteers
- 2010
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In: IRCOBI Conference – Hanover (Germany). - 9783033025509 ; , s. 29-39
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Conference paper (peer-reviewed)abstract
- In this study indications of differences in motion pattern of females and males have been found. The objective was to quantify dynamic motion responses of female and male volunteers in rear impact tests. Such data can be used as an input in the development process of improved occupant models such as computational models and crash test dummies.High-speed video data from rear impact tests at 4 km/h and 8 km/h with 12 female and 11 male volunteers was analysed. The females in this study had smaller rearward horizontal and angular motions of the head and T1 compared to the males. Furthermore, the females had more pronounced rebound motion.
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| 3. |
- Carlsson, Anna K, 1966, et al.
(author)
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Motion of the Head and Neck of Female and Male Volunteers in Rear Impact Car-to-Car Impacts
- 2012
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-9588 .- 1538-957X. ; 13:4, s. 378-387
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Journal article (peer-reviewed)abstract
- Objectives: The objectives of this study were to quantify and compare dynamic motion responses between 50th percentile female and male volunteers in rear impact tests. These data are fundamental for developing future occupant models for crash safety development and assessment.Methods: High-speed video data from a rear impact test series with 21 male and 21 female volunteers at 4 and 8 km/h, originally presented in Siegmund et al. (1997), were used for further analysis. Data from a subset of female volunteers, 12 at 4 km/h and 9 at 8 km/h, were extracted from the original data set to represent the 50th percentile female. Their average height was 163 cm and their average weight was 62 kg. Among the male volunteers, 11 were selected, with an average height of 175 cm and an average weight of 73 kg, to represent the 50th percentile male. Response corridors were generated for the horizontal and angular displacements of the head, T1 (first thoracic vertebra), and the head relative to T1. T-tests were performed with the statistical significance level of.05 to quantify the significance of the differences in parameter values for the males and females.Results: Several differences were found in the average motion response of the male and female volunteers at 4 and 8 km/h. Generally, females had smaller rearward horizontal and angular motions of the head and T1 compared to the males. This was mainly due to shorter initial head-to-head restraint distance and earlier head-to-head restraint contact for the females. At 8 km/h, the female volunteers showed 12 percent lower horizontal peak rearward head displacement (P =.018); 22 percent lower horizontal peak rearward head relative to T1 displacement (P =.018); and 30 percent lower peak head extension angle (P =.001). The females also had more pronounced rebound motion.Conclusions: This study indicates that there may be characteristic differences in the head-neck motion response between 50th percentile males and females in rear impacts. The exclusive use of 50th percentile male rear impact dummies may thus limit the assessment and development of whiplash prevention systems that adequately protect both male and female occupants. The results of this study could be used in the development and evaluation of a mechanical and/or computational average-sized female dummy model for rear impact safety assessment. These models are used in the development and evaluation of protective systems. It would be of interest to make further studies into seat configurations featuring a greater head-to-head restraint distance. © 2012 Copyright Taylor and Francis Group, LLC.
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| 4. |
- Carlsson, Anna, et al.
(author)
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Motion of the head and neck of female and male volunteers in rear impact car-to-car tests at 4 and 8 km/h
- 2010
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In: 2010 INTERNATIONAL IRCOBI CONFERENCE ON THE BIOMECHANICS OF INJURY 15. + 16. September 2010– HANOVER (Germany) PROCEEDINGS. ; , s. 29-39
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Conference paper (peer-reviewed)abstract
- In this study indications of differences in motion pattern of females and males have been found. The objective was to quantify dynamic motion responses of female and male volunteers in rear impact tests. Such data can be used as an input in the development process of improved occupant models such as computational models and crash test dummies. High-speed video data from rear impact tests at 4 km/h and 8 km/h with 12 female and 11 male volunteers was analysed. The females in this study had smaller rearward horizontal and angular motions of the head and T1 compared to the males. Furthermore, the females had more pronounced rebound motion.
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| 5. |
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| 6. |
- Fice, Jason, 1985, et al.
(author)
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Neck Muscle and Head/Neck Kinematic Responses While Bracing Against the Steering Wheel During Front and Rear Impacts
- 2021
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In: Annals of Biomedical Engineering. - : Springer Science and Business Media LLC. - 1573-9686 .- 0090-6964. ; 49:3, s. 1069-1082
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Journal article (peer-reviewed)abstract
- Drivers often react to an impending collision by bracing against the steering wheel. The goal of the present study was to quantify the effect of bracing on neck muscle activity and head/torso kinematics during low-speed front and rear impacts. Eleven seated subjects (3F, 8 M) experienced multiple sled impacts (Delta v = 0.77 m/s; a(peak) = 19.9 m/s(2), Delta t = 65.5 ms) with their hands on the steering wheel in two conditions: relaxed and braced against the steering wheel. Electromyographic activity in eight neck muscles (sternohyoid, sternocleidomastoid, splenius capitis, semispinalis capitis, semispinalis cervicis, multifidus, levator scapulae, and trapezius) was recorded unilaterally with indwelling electrodes and normalized by maximum voluntary contraction (MVC) levels. Head and torso kinematics (linear acceleration, angular velocity, angular rotation, and retraction) were measured with sensors and motion tracking. Muscle and kinematic variables were compared between the relaxed and braced conditions using linear mixed models. We found that pre-impact bracing generated only small increases in the pre-impact muscle activity (< 5% MVC) when compared to the relaxed condition. Pre-impact bracing did not increase peak neck muscle responses during the impacts; instead it reduced peak trapezius and multifidus muscle activity by about half during front impacts. Bracing led to widespread changes in the peak amplitude and timing of the torso and head kinematics that were not consistent with a simple stiffening of the head/neck/torso system. Instead pre-impact bracing served to couple the torso more rigidly to the seat while not necessarily coupling the head more rigidly to the torso.
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| 7. |
- Forman, Jason, et al.
(author)
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Variability in Body Shape, Superficial Soft Tissue Geometry, and Seatbelt Fit Relative to the Pelvis in Automotive Postures—Methods for Volunteer Data Collection With Open Magnetic Resonance Imaging
- 2024
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In: Journal of Biomechanical Engineering. - 0148-0731 .- 1528-8951. ; 146:3
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Journal article (peer-reviewed)abstract
- Variability in body shape and soft tissue geometry have the potential to affect the body’s interaction with automotive safety systems. In this study, we developed a methodology to capture information on body shape, superficial soft tissue geometry, skeletal geometry, and seatbelt fit relative to the skeleton—in automotive postures—using Open Magnetic Resonance Imaging (MRI). Volunteer posture and belt fit were first measured in a vehicle and then reproduced in a custom MRI-safe seat (with an MR-visible seatbelt) placed in an Open MR scanner. Overlapping scans were performed to create registered three-dimensional reconstructions spanning from the thigh to the clavicles. Data were collected with ten volunteers (5 female, 5 male), each in their self-selected driving posture and in a reclined posture. Examination of the MRIs showed that in the males with substantial anterior abdominal adipose tissue, the abdominal adipose tissue tended to overhang the pelvis, narrowing in the region of the Anterior Superior Iliac Spine (ASIS). For the females, the adipose tissue depth around the lower abdomen and pelvis was more uniform, with a more continuous layer superficial to the ASIS. Across the volunteers, the pelvis rotated rearward by an average of 62% of the change in seatback angle during recline. In some cases, the lap belt drew nearer to the pelvis as the volunteer reclined (as the overhanging folds of adipose tissue stretched). In others, the belt-to-pelvis distance increased as the volunteer reclined. These observations highlight the importance of considering both interdemographic and intrademographic variability when developing tools to assess safety system robustness.
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| 8. |
- Linder, Astrid, et al.
(author)
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Dynamic responses of female and male volunteers in rear impacts
- 2008
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-9588 .- 1538-957X. ; 9:6, s. 592-599
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Journal article (peer-reviewed)abstract
- Objectives: Whiplash injuries from vehicle collisions are common and costly. These injuries most frequently occur as a result of a rear impact and, compared to males, females have up to twice the risk of whiplash-associated disorders (WAD) resulting from vehicle crashes. The present study focuses on the differences in the dynamic response corridors of males and females in low-severity rear impacts.Methods: In this study, analysis of data from volunteer tests of females from previously published data has been performed. Corridors for the average female response were generated based on 12 volunteers exposed to a change of velocity of 4 km/h and 9 volunteers exposed to a change of velocity of 8 km/h. These corridors were compared to corridors for the average male response that were previously generated based on 11 male volunteers exposed to the same test conditions.Results: Comparison between the male and female data showed that the maximum x-acceleration of the head for the females occurred on average 10 ms earlier and was 29% higher during the 4 km/h test and 12 ms earlier and 9% higher during the 8 km/h test. Head-to-head restraint contact for the females occurred 14 ms earlier at 4 km/h and 11 ms earlier at 8 km/h compared to the males. For the same initial head-to-head restraint distance, head restraint contact occurred 11 and 7 ms earlier for the females than the males at 4 and 8 km/h, respectively. Furthermore, the calculated Neck Injury Criteria (NIC) values were similar for males and females at 4 km/h, whereas they were lower for females compared to the males at 8 km/h (3.2 and 4.0 m2/s2, respectively).Conclusions: The results of this study highlight the need to further investigate the differences in dynamic responses between males and females at low-severity impacts. Such data are fundamental for the development of future computer models and dummies for crash safety assessment. These models can be used not only as a tool in the design and development process of protective systems but also in the process of further evaluation and development of injury criteria. Copyright © 2008 Taylor & Francis Group, LLC.
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| 9. |
- Olafsdottir, Jóna Marin, 1985, et al.
(author)
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Cervical Muscle Responses to Multi-Directional Perturbations
- 2014
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In: 7th World Congress of Biomechanics.
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Conference paper (other academic/artistic)abstract
- Numerical human models are widely used in the design process and evaluation of passive and active vehicle safety systems in pre-crash and crash situations. Development and validation of human models that simulate neuromuscular control requires information on muscle activation patterns and contraction levels for different loading directions. Due to the lack of experimental data on cervical muscle recruitment strategies, the aim of this study was to provide activation patterns for superficial and deep cervical muscles during multidirectional perturbations.Eight volunteers received three perturbations (apeak=1.5g, ∆v=0.5m/s) in each of eight different directions while seated unrestrained on a sled-mounted car seat without a head restraint. Volunteers received no warning of perturbation onset. Electromyographic (EMG) activity was measured with wire electrodes inserted into the left sternocleidomastoid (SCM), trapezius (Trap), levator scapulae (LS), splenius capitis (SPL), semispinalis capitis (SCap), semispinalis cervicis (SCerv), and multifidus (Multi) muscles, and with surface electrodes over the sternohyoid (STH) muscle. All EMG signals were normalized with maximum voluntary isometric contraction activity.All median muscle activities were below 5%MVC before perturbation onset. During perturbation, most muscles showed distinctive activation patterns consistent with their anatomical location and function. Anterior muscles (SCM, STH) activated to counteract head extension and posterior muscles, except SPL, activated to counteract flexion (Figure). Although with different levels of contraction, SCap, SCerv, and Multi activated synergistically with the highest activity (89%, 50%, and 36%MVC respectively, 110ms after perturbation onset) during rearward and ipsilateral rearward oblique perturbations. Activation levels were generally five times lower in other directions. Despite its posterior location, SPL had activities between 19%MVC and 27%MVC during forward, forward oblique and lateral perturbations, but
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| 10. |
- Olafsdottir, Jóna Marin, 1985, et al.
(author)
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Dynamic Spatial Tuning of Cervical Muscle Reflexes to Multidirectional Seated Perturbations
- 2015
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In: Spine. - 0362-2436 .- 1528-1159. ; 40:4, s. E211-E219
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Journal article (peer-reviewed)abstract
- Study Design. Human volunteers were exposed experimentally to multidirectional seated perturbations.Objective. To determine the activation patterns, spatial distribution and preferred directions of reflexively activated cervical muscles for human model development and validation.Summary of Background Data. Models of the human head and neck are used to predict occupant kinematics and injuries in motor vehicle collisions. Because of a dearth of relevant experimental data, few models use activation schemes based on in vivo recordings of muscle activation and instead assume uniform activation levels for all muscles within presumed agonist or antagonist groups. Data recorded from individual cervical muscles are needed to validate or refute this assumption.Methods. Eight subjects (6 males, 2 females) were exposed to seated perturbations in 8 directions. Electromyography was measured with wire electrodes inserted into the sternocleidomastoid, trapezius, levator scapulae, splenius capitis, semispinalis capitis, semispinalis cervicis, and multifidus muscles. Surface electrodes were used to measure sternohyoid activity. Muscle activity evoked by the perturbations was normalized with recordings from maximum voluntary contractions.Results. The multidirectional perturbations produced activation patterns that varied with direction within and between muscles. Sternocleidomastoid and sternohyoid activated similarly in forward and forward oblique directions. The semispinalis capitis, semispinalis cervicis, and multifidus exhibited similar spatial patterns and preferred directions, but varied in activation levels. Levator scapulae and trapezius activity generally remained low, and splenius capitis activity varied widely between subjects.Conclusion. All muscles showed muscle- and direction-specific contraction levels. Models should implement muscle- and direction-specific activation schemes during simulations of the head and neck responses to omnidirectional horizontal perturbations where muscle forces influence kinematics, such as during emergency maneuvers and low-severity crashes.Level of Evidence: N/A
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| 11. |
- Olafsdottir, Jóna Marin, 1985, et al.
(author)
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Trunk muscle recruitment patterns in simulated precrash events
- 2018
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 19, s. S186-S188
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Journal article (peer-reviewed)abstract
- Objectives: To quantify trunk muscle activation levels during whole body accelerations that simulate precrash events in multiple directions and to identify recruitment patterns for the development of active human body models. Methods: Four subjects (1 female, 3 males) were accelerated at 0.55 g (net Δv = 4.0 m/s) in 8 directions while seated on a sled-mounted car seat to simulate a precrash pulse. Electromyographic (EMG) activity in 4 trunk muscles was measured using wire electrodes inserted into the left rectus abdominis, internal oblique, iliocostalis, and multifidus muscles at the L2–L3 level. Muscle activity evoked by the perturbations was normalized by each muscle's isometric maximum voluntary contraction (MVC) activity. Spatial tuning curves were plotted at 150, 300, and 600 ms after acceleration onset. Results: EMG activity remained below 40% MVC for the three time points for most directions. At the 150- and 300 ms time points, the highest EMG amplitudes were observed during perturbations to the left (–90°) and left rearward (–135°). EMG activity diminished by 600 ms for the anterior muscles, but not for the posterior muscles. Conclusions: These preliminary results suggest that trunk muscle activity may be directionally tuned at the acceleration level tested here. Although data from more subjects are needed, these preliminary data support the development of modeled trunk muscle recruitment strategies in active human body models that predict occupant responses in precrash scenarios.
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| 12. |
- Siegmund, Gunter P., et al.
(author)
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Letter to the editor
- 2019
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In: Spine. - Malmö : Malmö universitet. - 1528-1159 .- 0362-2436. ; 44:2, s. E133-E133:1, s. i-i
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Journal article (other academic/artistic)
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| 13. |
- Siegmund, Gunter P., et al.
(author)
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The Anatomy and Biomechanics of Acute and Chronic Whiplash Injury
- 2009
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In: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 10:2, s. 101-112
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Journal article (peer-reviewed)abstract
- Whiplash injury is the most common motor vehicle injury, yet it is also one of the most poorly understood. Here we examine the evidence supporting an organic basis for acute and chronic whiplash injuries and review the anatomical sites within the neck that are potentially injured during these collisions. For each proposed anatomical site—facet joints, spinal ligaments,intervertebral discs, vertebral arteries, dorsal root ganglia, and neck muscles—we present the clinical evidence supporting that injury site, its relevant anatomy, the mechanism of and tolerance to injury, and the future research needed to determinewhether that site is responsible for some whiplash injuries. This article serves as a snapshot of the current state of whiplash biomechanics research and provides a roadmap for future research to better understand and ultimately prevent whiplash injuries.
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| 14. |
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| 15. |
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| 16. |
- Soltan, Nikoo, et al.
(author)
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Validating a Device for Whiplash Motion Simulation in a Porcine Model
- 2021
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Conference paper (other academic/artistic)abstract
- Whiplash injury is a common outcome following minor automobile collisions. One theorized mechanism for whiplash injury is that the rapid head and neck motions induced by a collision can injure nerve cells in the dorsal root ganglia through pressure gradients developed in the spinal canal and surrounding tissues. This injury mechanism has previously been studied in human cadaver and porcine models. However, the whiplash motion simulation methods in the latter studies lacked the control necessary to explore the independent effects of head rotation and retraction on the measured spinal pressures. This project aimed to address the limitations of previous porcine whiplash studies by developing and validating a new whiplash motion simulation device to enable further study of this injury mechanism. The new proposed device consists of two servomotors which can be programmed to precisely actuate a headplate through mechanical linkages. For the current study, an inert surrogate model was used for preliminary testing of the device using a whiplash motion profile from previous porcine studies. The time scale of the motion profile was adjusted to incrementally increase severity. The positional accuracy and repeatability of the device was assessed through marker tracking of the headplate and logging of the motor encoder positions. Angular rates and linear accelerations of the plate were also measured. Testing demonstrated the strengths of the proposed device in accurately and repeatably replicating programmed motion profiles. Some design modifications can potentially enable simulating whiplash motion severities commensurate with previous porcine whiplash studies. With future testing using this device, our understanding of the pressure-induced whiplash injury mechanism can be improved, which can inform effective treatments and preventative measures for whiplash injury.
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