Abstract.[Purpose] The present study investigated whether moving the front extremity forward over the center of mass at the moment of initial contact or moving the rear extremity backward at the moment of preswing affects the elongation of step length. [Subjects and Methods] Step length can be subdivided into touch down distance (TD), release distance (RD) and displacement during the double stance phase (DD). The subjects were 6 healthy men. The target walking speeds were 1.3 m/s, 1.9 m/s, and 2.5 m/s. Walking was recorded using three high-speed cameras.[Results]Step length increased linearly with walking speed, showing a significant relationship (r=0.74). TD increased as walking speed rose from 1.3 m/s to 1.9 m/s, then decreased after 1.9 m/s. No significant correlations were found between step length and TD. RD demonstrated a significant positive correlation with step length (r=0.50) and also showed significant positive correlations with external pelvic rotation angle (r=0.56), hip extension angle (r=0.61), and ankle plantar flexion angle (r=0.50) at the moment of foot release. [Conclusion] These results indicate that moving the rear extremity backward at the moment of foot release can thus be reasonably be expected to cause elongation of step length.