scholarly journals Kinetic and Kinematic Features of Pedestrian Avoidance Behavior in Motor Vehicle Conflicts

2021 ◽  
Vol 9 ◽  
Author(s):  
Quan Li ◽  
Shi Shang ◽  
Xizhe Pei ◽  
Qingfan Wang ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Injury Risk ◽  
Muscle Activation ◽  
Motor Vehicle ◽  
Movement Velocity ◽  
Physiological Signal ◽  
Avoidance Behaviors ◽  
Active Safety Systems ◽  
Traffic Conflict ◽  
Human Body Models ◽  
Biomechanical Features

The active behaviors of pedestrians, such as avoidance motions, affect the resultant injury risk in vehicle–pedestrian collisions. However, the biomechanical features of these behaviors remain unquantified, leading to a gap in the development of biofidelic research tools and tailored protection for pedestrians in real-world traffic scenarios. In this study, we prompted subjects (“pedestrians”) to exhibit natural avoidance behaviors in well-controlled near-real traffic conflict scenarios using a previously developed virtual reality (VR)-based experimental platform. We quantified the pedestrian–vehicle interaction processes in the pre-crash phase and extracted the pedestrian postures immediately before collision with the vehicle; these were termed the “pre-crash postures.” We recorded the kinetic and kinematic features of the pedestrian avoidance responses—including the relative locations of the vehicle and pedestrian, pedestrian movement velocity and acceleration, pedestrian posture parameters (joint positions and angles), and pedestrian muscle activation levels—using a motion capture system and physiological signal system. The velocities in the avoidance behaviors were significantly different from those in a normal gait (p < 0.01). Based on the extracted natural reaction features of the pedestrians, this study provides data to support the analysis of pedestrian injury risk, development of biofidelic human body models (HBM), and design of advanced on-vehicle active safety systems.

The Influence of Gait Stance and Vehicle Type on Pedestrian Kinematics and Injury Risk

2020 ◽  
Author(s):  
Wansoo Pak ◽  
Daniel Grindle ◽  
Costin Untaroiu
Keyword(s):  
Injury Risk ◽  
Bone Fractures ◽  
Leading Edge ◽  
Pedestrian Protection ◽  
Head Region ◽  
Vehicle Type ◽  
Low Profile ◽  
Active Safety Systems ◽  
The Usa ◽  
Human Body Models

Abstract Pedestrians are one of the most vulnerable road users. In 2018 the USA reported the highest number of pedestrian fatalities number in nearly three decades. Government safety agencies and car manufacturers have started paying greater attention towards pedestrian protection. The pre-impact conditions of Car-to-Pedestrian Collisions (CPC) varies significantly in terms of the characteristics of vehicles (e.g. front-end geometry, stiffness, etc.) and pedestrians (e.g. anthropometry, posture, etc.). The influence of vehicle type and pedestrian gait has not been analyzed. The purpose of this study was to numerically investigate the changes in pedestrian kinematics and injuries across various gait postures and two different car types. Five finite element (FE) human body models, representing 50th percentile male in gait cycle, were developed and used to perform CPC simulations with two generic vehicle FE models representing a family car (FCR), and a sport utility vehicle (SUV). In the impacts with the high-profile vehicle (SUV), the pedestrian models usually slide above the bonnet leading edge and report shorter wrap around distances (WAD) than in low-profile vehicle (FCR) impacts. The pedestrian postures influenced the post-impact rotation of the pedestrian and consequently, the impacted head region. The pedestrian posture also influenced the risk of injuries in the lower extremities. Higher risk of bone fractures was observed in the stance phase posture compared to the swing phase. The findings of this study should be taken into consideration when examining pedestrian protection protocols. In addition, the results of this study can be used to improve the design of active safety systems used to protect pedestrians in collisions.

Multilevel Validation of a Male Neck Finite Element Model With Active Musculature

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Jeffrey B. Barker ◽  
Duane S. Cronin
Keyword(s):  
Cervical Spine ◽  
Injury Risk ◽  
Muscle Activation ◽  
Computational Models ◽  
Soft Tissues ◽  
Motor Vehicle ◽  
Experimental Studies ◽  
Tissue Level ◽  
Open Loop ◽  
Frontal Impact

Abstract Computational models of the human neck have been developed to assess human response in impact scenarios; however, the assessment and validation of such models is often limited to a small number of experimental data sets despite being used to evaluate the efficacy of safety systems and potential for injury risk in motor vehicle collisions. In this study, a full neck model (NM) with active musculature was developed from previously validated motion segment models of the cervical spine. Tissue mechanical properties were implemented from experimental studies, and were not calibrated. The neck model was assessed with experimental studies at three levels of increasing complexity: ligamentous cervical spine in axial rotation, axial tension, frontal impact, and rear impact; postmortem human subject (PMHS) rear sled impact; and human volunteer frontal and lateral sled tests using an open-loop muscle control strategy. The neck model demonstrated good correlation with the experiments ranging from quasi-static to dynamic, assessed using kinematics, kinetics, and tissue-level response. The contributions of soft tissues, neck curvature, and muscle activation were associated with higher stiffness neck response, particularly for low severity frontal impact. Experiments presenting single-value data limited assessment of the model, while complete load history data and cross-correlation enabled improved evaluation of the model over the full loading history. Tissue-level metrics demonstrated higher variability and therefore lower correlation relative to gross kinematics, and also demonstrated a dependence on the local tissue geometry. Thus, it is critical to assess models at the gross kinematic and the tissue levels.

scholarly journals The influence of body side and sex on neck muscle responses to left-frontal-oblique impacts

2020 ◽  
Author(s):  
Andreas Mühlbeier ◽  
Kim Joris Boström ◽  
Marc H. E. de Lussanet ◽  
Wolfram Kalthoff ◽  
Cassandra Kraaijenbrink ◽  
...  
Keyword(s):  
Injury Risk ◽  
Muscle Activation ◽  
Motor Vehicle ◽  
Oblique Impact ◽  
Neck Muscle ◽  
Low Velocity ◽  
Oblique Collision ◽  
Cervical Muscles ◽  
The Impact ◽  
Muscle Responses

ABSTRACTLow-velocity motor vehicle crashes frequently induce chronic neck disorders also referred to as whiplash-associated disorders (WAD). The etiology of WAD is still not fully understood. Women are affected more often and more severely than men. A frontal-oblique collision direction leads to WAD relatively frequently, but is poorly investigated as compared to rear-end or frontal collision directions. An oblique impact direction is assumed to strain the contralateral neck side more than the ipsilateral side, provoking an asymmetrical response pattern of the left and right cervical muscles. In this study, we examined the muscle reflex responses of the sternocleidomastoid, the paraspinal, and the trapezius muscles as well as the kinematic responses of 60 subjects during left-frontal-oblique collisions. Neither the reflex delay nor the peak head acceleration revealed significant sex differences. Thus, the elsewhere reported higher injury risk of females as compared to males cannot be explained by the electromyographic and kinematic results of this study. In females as well as in males the right muscle responses revealed shorter onset times than the left muscle responses. Thus, cervical muscles seem to be activated depending on the specific direction of the impact. Moreover, the difference between right and left muscle responses cannot be explained by a startle reflex. The movement of the head in relation to the torso (female mean ± SD: 92 ± 16 ms; male: 87 ± 16 ms) started almost simultaneously to the onset of the first muscle activation (right paraspinal muscles: female mean: 95 ms and 95%-CI 82 − 109; male mean: 95 ms and 95%-CI 84 − 108) indicating that the initial muscle activity seems not to be triggered by a stretch reflex in the PARA muscles.

The Influence of Gait Stance and Vehicle Type On Pedestrian Kinematics and Injury Risk

2021 ◽  
Author(s):  
Wansoo Pak ◽  
Daniel Grindle ◽  
Costin Untaroiu
Keyword(s):  
Injury Risk ◽  
Leading Edge ◽  
Head Region ◽  
High Profile ◽  
Low Profile ◽  
Active Safety Systems ◽  
The Usa ◽  
Post Impact ◽  
Human Body Models ◽  
Safety Systems

Abstract Pedestrians are one of the most vulnerable road users. In 2019, the USA reported the highest number of pedestrian fatalities in nearly three decades. The pre-impact conditions of Car-to-Pedestrian Collisions (CPC) vary significantly in terms of vehicles characteristics (e.g. front-end geometry, stiffness, etc.) and pedestrian characteristics (e.g. anthropometry, posture, etc.). The influence of pedestrian gait posture on CPC injury outcomes has not been well analyzed. The purpose of this study was to numerically investigate the changes in pedestrian kinematics and injuries across various gait postures in two different vehicle impacts. Five finite element (FE) human body models, that represent the 50th percentile male through the gait cycle, were developed and used to perform CPC simulations with two generic vehicle models representing a low-profile and high-profile vehicle. In the impacts with the high-profile vehicle, the pedestrian models usually slid above the bonnet leading edge and reported shorter wrap around distances than the low-profile vehicle impacts. The pedestrian postures influenced the post-impact rotation of the pedestrian and consequently, the impacted head region. Pedestrian posture also influenced the risk of injuries in the lower and upper extremities. Higher bone bending moments were observed in the stance phase posture compared to the swing phase. The findings of this study should be taken into consideration when examining pedestrian protection protocols. In addition, the results of this study can be used to improve the design of active safety systems used to protect pedestrians in collisions.

Morphomic Analysis of Thoracic Injury Risk in Live Subjects From Real World Motor Vehicle Crashes

2014 ◽  
Vol 186 (2) ◽  
pp. 659-660
Author(s):  
E.T. Chang ◽  
S. Holcombe ◽  
C. Kohoyda-Inglis ◽  
J.B. MacWilliams ◽  
C. Parenteau ◽  
...  
Keyword(s):  
Real World ◽  
Injury Risk ◽  
Motor Vehicle ◽  
Motor Vehicle Crashes ◽  
Thoracic Injury ◽  
Vehicle Crashes

scholarly journals Mechanisms of Hamstring Strain Injury: Interactions between Fatigue, Muscle Activation and Function

Sports ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 65 ◽  
Author(s):  
Shaun Huygaerts ◽  
Francesc Cos ◽  
Daniel D. Cohen ◽  
Julio Calleja-González ◽  
Marc Guitart ◽  
...  
Keyword(s):  
High Intensity ◽  
Injury Risk ◽  
Muscle Activation ◽  
Injury Mechanism ◽  
Hamstring Injury ◽  
Current Evidence ◽  
Hamstring Muscle ◽  
Hamstring Strain ◽  
And Function

Isolated injury to the long head of biceps femoris is the most common type of acute hamstring strain injury (HSI). However, the precise hamstring injury mechanism (i.e., sprint-type) is still not well understood, and research is inconclusive as to which phase in the running cycle HSI risk is the greatest. Since detailed information relating to hamstring muscle function during sprint running cannot be obtained in vivo in humans, the findings of studies investigating HSI mechanisms are based on modeling that requires assumptions to be made based on extrapolations from anatomical and biomechanical investigations. As it is extremely difficult to account for all aspects of muscle-tendon tissues that influence function during high-intensity running actions, much of this complexity is not included in these models. Furthermore, the majority of analyses do not consider the influence of prior activity or muscular fatigue on kinematics, kinetics and muscle activation during sprinting. Yet, it has been shown that fatigue can lead to alterations in neuromuscular coordination patterns that could potentially increase injury risk. The present critical review will evaluate the current evidence on hamstring injury mechanism(s) during high-intensity running and discuss the interactions between fatigue and hamstring muscle activation and function.

Body mass index and injury risk among US children 9-15 years old in motor vehicle crashes

2008 ◽  
Vol 14 (6) ◽  
pp. 366-371 ◽  
Author(s):  
K M Pollack ◽  
D Xie ◽  
K B Arbogast ◽  
D R Durbin
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Injury Risk ◽  
Motor Vehicle ◽  
Motor Vehicle Crashes ◽  
Vehicle Crashes ◽  
Us Children

Children with Special Physical Health Care Needs: Restraint Use and Injury Risk in Motor Vehicle Crashes

2009 ◽  
Vol 15 (7) ◽  
pp. 949-954 ◽  
Author(s):  
Patty Huang ◽  
Michael J. Kallan ◽  
Joseph O’Neil ◽  
Marilyn J. Bull ◽  
Nathan J. Blum ◽  
...  
Keyword(s):  
Health Care ◽  
Physical Health ◽  
Injury Risk ◽  
Motor Vehicle ◽  
Motor Vehicle Crashes ◽  
Health Care Needs ◽  
Vehicle Crashes ◽  
Care Needs ◽  
Restraint Use ◽  
Physical Health Care

scholarly journals Effects of Different Combinations of Concentric and Eccentric Resistance Training Programs on Traditional and Alternative Hamstrings-to-Quadriceps Ratios

Sports ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 221 ◽  
Author(s):  
Cassio V. Ruas ◽  
Ronei S. Pinto ◽  
Guy G. Haff ◽  
Camila D. Lima ◽  
Lee E. Brown
Keyword(s):  
Resistance Training ◽  
Injury Risk ◽  
Muscle Activation ◽  
Training Programs ◽  
Knee Extension ◽  
Muscle Size ◽  
Ligament Injury ◽  
Knee Ligament ◽  
Knee Ligament Injury ◽  
Muscle Balance

Resistance training is often recommended for combined increases in traditional and alternative hamstrings-to-quadriceps (H:Q) ratios in order to reduce knee strength imbalance and associated hamstrings and knee ligament injury risk. The aim of this study was to investigate the effect of different concentric and eccentric resistance training programs on traditional and alternative H:Q ratios. Forty male volunteers were assigned to one of 4 groups: concentric quadriceps and concentric hamstrings (CON/CON, n = 10), eccentric quadriceps and eccentric hamstrings (ECC/ECC, n = 10), concentric quadriceps and eccentric hamstrings (CON/ECC, n = 10), or no training (control (CNTRL), n = 10). Traditional conventional (CR) and functional (FR), alternative rate of torque development (RTD), muscle size (MS), and muscle activation (MA) H:Q ratios were measured before and after six weeks of unilateral nondominant knee extension–flexion resistance training performed on an isokinetic dynamometer. The ECC/ECC training significantly increased FR (pre = 0.75 ± 0.11; post = 0.85 ± 0.15), whereas the lack of training (CNTRL) decreased the RTD H:Q ratio (pre = 1.10 ± 0.67; post = 0.73 ± 0.33). There were no differences between groups for the other traditional and alternative ratios following resistance training protocols. These findings suggest eccentric exercise for quadriceps and hamstrings as the most beneficial training program for inducing increases in the traditional FR. However, different resistance training strategies may be needed to also elicit increases in the alternative RTD, MS, and MA H:Q ratios for fully restoring muscle balance and reducing potential hamstrings and knee ligament injury risk.

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