Changes in practice schedule and functional task difficulty: a study using the probe reaction time technique.

[Purpose] Motor learning is accelerated most by optimized task difficulty. When task difficulty is optimized, the amount of information required to complete the task matches the learner's information processing abilities. The practice schedule is one of the factors which changes the amount of task information. We investigated the influence of changes in practice schedule on the amount of task information using the probe reaction time technique. [Methods] Fourteen young male subjects were randomly assigned to a blocked or random practice group. They were required to perform two tasks simultaneously. The primary task consisted of treadmill walking with specific step lengths, and the secondary task consisted of a probe reaction time task. [Results] The blocked practice group was superior to the random practice group in performance during the acquisition phase. In contrast, the random practice group was superior to the blocked practice group in performance during the retention phase. Furthermore, the random practice group had a longer reaction time than the blocked practice group. [Conclusion] From the standpoint of the challenge point framework, motor learning may be accelerated by random practice because random practice probably elicits greater attentional demand than blocked practice.