... Among the techniques for competitive swimming, the arm stroke in freestyle was focused in the present study. The arm stroke is very important in freestyle, since the main component of the thrust is considered to be generated by the arm stroke (Hollander et al., 1988). For this reason, many studies related to the arm stroke have been conducted to date (Schleihauf et al., 1983, Schleihauf et al., 1988, Berger et al., 1995, Bixler and Riewald, 2002, Sato and Hino, 2003, Rouboa et al., 2006, Pai, 1987, Kudo et al., 2007, Sidelnik and Young, 2006, Nakashima and Takahashi, 2012a, Nakashima and Takahashi, 2012b, Takagi and Sanders, 2002, Matsuuchi et al., 2009, Ito and Okuno, 2003, Ito, 2007. ...