title: Evaluation of the biofidelity of the HIII and MIL-Lx lower leg surrogates under axial impact loading.
abstract: OBJECTIVE
  Lower leg injury risk is commonly assessed using an anthropomorphic test device (ATD). The current standard leg (the HIII) has been shown to have low biofidelity due to its geometry and material properties. A new surrogate (the MIL-Lx) was developed to address these issues, specifically for anti-vehicular mine blast scenarios but with potential applications to high-force crashes in the automotive industry. Before it is adopted for use, the MIL-Lx must be evaluated under impact loading to ensure that it represents the natural lower leg response.
  
  
  METHODS
  Axial impact loads were applied to both the HIII and the MIL-Lx at impact velocities of 2 to 7 m/s using a pneumatic impacting device. Testing was also conducted with the foot removed from both surrogates to enable comparison with previous tests of isolated cadaveric tibias at noninjurious and injurious (i.e., fracture) levels. To evaluate the effect of a boot on load attenuation, the HIII was impacted with and without a hiking boot.
  
  
  RESULTS
  Forces in the MIL-Lx were between 25 and 100 percent of those in the HIII (depending on impact conditions). The use of a boot reduced the peak force by approximately 65 percent at the highest impact velocities. The MIL-Lx fit the data from noninjurious cadaveric tibia tests with R(2) = 0.83.
  
  
  CONCLUSIONS
  The MIL-Lx is a new surrogate that represents the response of the natural tibia under axial impact loading better than the HIII. The inclusion of a boot has a significant effect on loads in the leg and may influence injury assessment results. The MIL-Lx will be a useful tool for predicting lower leg injury risk over a wide range of impact velocities.
authors.affiliation: Liburdi Biomechanics Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada. quennev@mcmaster.ca
authors.forename: Cheryl E
authors.initials: CE
authors.lastname: Quenneville
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Dunning
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic / Q000706:statistics & numerical data; D002102:Cadaver; D006801:Humans; D008348:Manikins; D011481:Protective Clothing; D015203:Reproducibility of Results; D018570:Risk Assessment; D013314:Stress, Mechanical; D013977:Tibia / Q000502:physiology*; D013978:Tibial Fractures / Q000503:physiopathology*