title: Dynamic kinematic responses of female volunteers in rear impacts and comparison to previous male volunteer tests.
abstract: OBJECTIVE
  The objective was to quantify dynamic responses of 50th percentile females in rear impacts and compare to those from similar tests with males. The results will serve as a basis for future work with models, criteria, and safety systems.
  
  
  METHODS
  A rear impact sled test series with 8 female volunteers was performed at velocity changes of 5 and 7 km/h. The following dynamic response corridors were generated for the head, T1 (first thoracic vertebra) and head relative to T1: (1) accelerations in posterior-anterior direction, (2) horizontal and vertical displacements, (3) angular displacements for 6 females close to the 50th percentile in size. Additionally, the head-to-head restraint distance and contact time and neck injury criterion (NIC) were extracted from the data set. These data were compared to results from previously performed male volunteer tests, representing the 50th percentile male, in equivalent test conditions. T-tests were performed with the statistical significance level of .05 to quantify the significance of the parameter value differences for the males and females.
  
  
  RESULTS
  At 7 km/h, the females showed 29 percent earlier head-to-head restraint contact time (p = .0072); 27 percent shorter horizontal rearward head displacement (p = .0017); 36 percent narrower head extension angle (p = .0281); and 52 percent lower NIC value (p = .0239) than the males in previous tests. This was mainly due to 35 percent shorter initial head-to-head restraint distance for the females (p = .0125). The peak head acceleration in the posterior-anterior direction was higher and occurred earlier for the females.
  
  
  CONCLUSIONS
  The overall result indicated differences in the dynamic response for the female and male volunteers. The results could be used in developing and evaluating a mechanical and/or mathematical average-sized female dummy model for rear impact safety assessment. These models can be used as a tool in the design of protective systems and for further development and evaluation of injury criteria.
authors.affiliation: Applied Mechanics/SAFER Centre, Vehicle Safety Division, Chalmers University of Technology, Göteborg, Sweden. anna.carlsson@chalmers.se
authors.forename: Anna
authors.initials: A
authors.lastname: Carlsson
authors.forename: Astrid
authors.initials: A
authors.lastname: Linder
authors.forename: Johan
authors.initials: J
authors.lastname: Davidsson
authors.forename: Wolfram
authors.initials: W
authors.lastname: Hell
authors.forename: Sylvia
authors.initials: S
authors.lastname: Schick
authors.forename: Mats
authors.initials: M
authors.lastname: Svensson
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D001696:Biomechanical Phenomena; D049628:Body Size; D005260:Female; D019416:Head Movements / Q000502:physiology*; D006260:Head Protective Devices; D006805:Human Experimentation / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D012737:Sex Factors; D014911:Whiplash Injuries / Q000209:etiology / Q000503:physiopathology*; D055815:Young Adult