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From the *Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, Oslo, Norway; and †Department Sport Equipment and Materials, Institute for Ergonomics, Faculty of Mechanical Engineering, Technische Universität München, München, Germany.
Submitted for publication September 17, 2010; accepted March 3, 2011.
The authors report no conflict of interest.
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Corresponding Author: Hideyuki Koga, MD, PhD, Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, PO Box 4014 Ullevaal Stadion, 0806 Oslo, Norway (firstname.lastname@example.org).