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 (EMBC, 2017)