The purpose of this study is to clarify the effect of the method of KR providing on motor learning and functional task difficulty using the probe reaction time technique. Fourteen young male participants were randomly assigned to one of two groups (immediately KR and summary KR). Participants were required to perform two tasks simultaneously. The primary task consisted of a treadmill walk with specific step lengths, and the secondary task consisted of a probe reaction time task. The results suggested that motor learning may be accelerated by summary KR since summary KR probably elicited moderate functional task difficulty.