Comparison of Kinematic Responses of the Head and Spine for Children and Adults in Low-Speed Frontal Sled Tests

Kristy B. Arbogast, Sriram Balasubramanian, Thomas Seacrist, Matthew R. Maltese, J. Felipe Garcia-Espana, Terrence Hopely, Eric Constans, Francisco J. Lopez-Valdes, Richard W. Kent, Hiromasa Tanji, Kazuo Higuchi

Research output: Contribution to journalConference article

77 Scopus citations

Abstract

Previous research has suggested that the pediatric ATD spine, developed from scaling the adult ATD spine, may not adequately represent a child's spine and thus may lead to important differences in the ATD head trajectory relative to a human. To gain further insight into this issue, the objectives of this study were, through non-injurious frontal sled tests on human volunteers, to 1) quantify the kinematic responses of the restrained child's head and spine and 2) compare pediatric kinematic responses to those of the adult. Low-speed frontal sled tests were conducted using male human volunteers (20 subjects: 6-14 years old, 10 subjects: 18-40 years old), in which the safety envelope was defined from an amusement park bumper-car impact. Each subject was restrained by a custom-fit lap and shoulder belt system and photo-reflective targets were attached to a tight-fitting cap worn on the head or adhered to the skin overlying skeletal landmarks on the head, spine, shoulders, sternum, and legs. A 3-D near-infrared target tracking system quantified the position of the following markers: head top, external auditory meatus, nasion, opisthocranion, C4, T1, T4, and T8. Trajectory data were normalized by subject seated height and head and spine rotations were calculated. The Generalized Estimating Equations method was used to determine the effect of age and key anthropometric measures on marker excursion. For all markers, the normalized forward excursion significantly decreased with age and all spinal markers moved upward due to a combination of rigid body rotation and spinal flexion with lesser upward movement with age. The majority of the spine flexion occurred at the base of the neck not in the upper cervical spine and the magnitude of flexion was greatest for the youngest subjects. Additional flexion occurred in the thoracic spine as well. Our findings indicate that the primary factor governing the differences in normalized head and spinal trajectories between the various age groups was decreasing head-to-neck girth ratio with increasing age. Other factors, such as muscle response and cervical vertebral structural properties, may also contribute to the differences, but were not evaluated in this paper. These results can serve as a data set for validating the responses of restrained ATDs and computational human models to low severity frontal collisions.

Original languageEnglish (US)
JournalSAE Technical Papers
Volume2009-November
Issue numberNovember
DOIs
StatePublished - Nov 2 2009
Event53rd SAE Stapp Car Crash Conference, STAPP 2009 - Savannah, United States
Duration: Nov 2 2009Nov 4 2009

All Science Journal Classification (ASJC) codes

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering

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    Arbogast, K. B., Balasubramanian, S., Seacrist, T., Maltese, M. R., Garcia-Espana, J. F., Hopely, T., Constans, E., Lopez-Valdes, F. J., Kent, R. W., Tanji, H., & Higuchi, K. (2009). Comparison of Kinematic Responses of the Head and Spine for Children and Adults in Low-Speed Frontal Sled Tests. SAE Technical Papers, 2009-November(November). https://doi.org/10.4271/2009-22-0012