The external force associated with callus formation under the first metatarsal head is reduced by wearing rocker sole shoes - Ayumi Amemiya; Rena Okonogi; Hiroki Yamakawa; Kaori Susumu; Tatsuya Jitsuishi; Hisayoshi Sugawara; Yuji L. Tanaka; Masatoshi Komiyama; Taketoshi Mori (2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), Jeju Island, South Korea, July 11-15, 2017, 2017)