Citation

Yamazaki J, Gilgien M, Kleiven S, McIntosh AS, Nachbauer W, Muller E, Bere T, Bahr R, Krosshaug T. Med. Sci. Sports Exerc. 2014; 47(6): 1113-1118.

Affiliation

1Oslo Sports Trauma Research Center, Oslo, Norway; 2Section of Orthopedic Surgery, School of Medicine, Tokyo Medical and Dental University Hospital, Tokyo, Japan; 3Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway; 4Royal Institute of Technology, Stockholm Sweden; 5Australian Centre for Research into Injury in Sport and its Prevention (ACRISP), Federation University Australia, Ballarat, Australia; 6Dept. of Sport Science, University of Innsbruck, Innsbruck, Austria; 7Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria; 8Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.

Copyright

(Copyright © 2014, Lippincott Williams and Wilkins)

DOI

10.1249/MSS.0000000000000511

PMID

25207934

Abstract

Traumatic brain injury (TBI) is the leading cause of death in alpine skiing. It has been found that helmet use can reduce the incidence of head injuries between 15% and 60%. However, knowledge on optimal helmet performance criteria in World Cup alpine skiing is currently limited due to lack of biomechanical data from real crash situations.

PURPOSE: This study aimed to estimate impact velocities in a severe TBI case in World Cup alpine skiing.

METHODS: Video sequences from a TBI case in World Cup alpine skiing were analyzed using a Model-Based Image Matching (MBIM) technique. Video sequences from four camera views were obtained in full high definition (1080p) format. A 3D model of the course was built based on accurate measurements of piste landmarks and matched to the background video footage using the animation software Poser 4. A trunk-neck-head model was utilized for tracking the skier's trajectory.

RESULTS: Immediately before head impact, the downward velocity component was estimated to be 8 m/s. After impact, the upwards velocity was 3 m/s, whereas the velocity parallel to the slope surface was reduced from 33 m/s to 22 m/s. The frontal plane angular velocity of the head changed from 80 rad/s left tilt immediately before impact to 20 rad/s right tilt immediately after impact.

CONCLUSION: A unique combination of HD video footage and accurate measurements of landmarks in the slope made possible a high quality analysis of head impact velocity in a severe TBI case. The estimates can provide crucial information on how to prevent TBI through helmet performance criteria and design.

Language: en