1. 1) Dick R, Ferrara MS, Agel J, Courson R, Marshall SW, Hanley MJ and Reifsteck F. 2007. Descriptive epidemiology of collegiate men’s football injuries: National Collegiate Athletic Association Injury Surveillance System,1988-1989 through 2003-2004. J Athl Train 42: 221-233.
2. 2) Fukuda T, Miyakawa S, Matsumoto T, Kawasaki A, Takemura M and Mori S. 2012. Epidemiology of collegiate American football injuries–longitudinal injury surveillance for 10 years, 1999 through 2008. Football Sci 9: 70-78 (in Japanese).
3. 3) Torg JS. 1990. Cervical spinal stenosis with cord neurapraxia and transient quadriplegia. Clin Sports Med 9: 279-296.
4. 4) Watanabe H, Takeda N, Torii N and Torii S. 2001. A longitudinal study about the morphology of the cervical vertebral body in collegiate American football players. Jpn J Phys Fitness Sports Med 50: 97-104 (in Japanese).
5. 5) Niitsu M, Kuno S, Anno I, Matsumoto K, Akisada M, Shimojyo H and Miyamaru M. 1989. MRI survey for neck injuries of American-football athletes. Jpn J Phys Fitness Sports Med 38: 678 (in Japanese).