Yasuchika Aoki*, Arata Nakajima, Ryuji Sakakibara, Seiji Ohtori, Kazuhisa Takahashi and Koichi Nakagawa
* Corresponding author: Yasuchika Aoki yasuaoki35@fc4.so-net.ne.jp
BMC Musculoskeletal Disorders 2013, 14:61 doi:10.1186/1471-2474-14-61