The effects of inaccessible visual feedback used concurrently or terminally

[Purpose] Concurrent feedback is more detrimental for long-term retention of motor skills because learners depend on accessible visual information provided in parallel with movements. However, visual information is not always accessible. Furthermore, the effects of concurrent feedback vary with aspects of the task being performed. We investigated the effects of inaccessible visual feedback used concurrently or terminally, focusing on aspects of movement. [Subjects and Methods] Fourteen subjects were quasi-randomly assigned to either a concurrent feedback group or a terminal feedback group. They practiced a task that involved right shoulder flexion with a specific acceleration. Learning achievements were assessed by measurement of errors in movement duration, peak timing, and strength. [Results] Regarding errors in movement duration, the concurrent feedback group was superior to the terminal feedback group during the midterm and final sessions. Regarding errors in peak timing, learning occurred in the concurrent feedback group, but not in the terminal feedback group because the improvement in performance during practice was inadequate. Regarding errors in peak strength, learning occurred in both groups. [Conclusion] Concurrent visual feedback that is used inaccessibly has learning effects that either equal or surpass those of terminal feedback that is used with inaccessible visual information for all parameters.