This study examined the effects of summary feedback and self-estimation about movement re-suits using a task in which a ball was thrown at a backward target. Acquisition trials were per-formed on four consecutive days. Practice for each day was composed of 48 trials. A 10-trial retention test was administered three days after the 4th day of acquisition trial sessions. None of the main effects for summary feedback, the main effect for self-estimation, and the summary feedback × self-estimation interaction were significant. The lack of a self-estimation effect seemed to be due mainly to task characteristics, which made participants of all groups estimate performance even if they were not instructed to do so. The lack of an effect for summary feedback also seemed to be due to task characteristics, which required participants to compensate variables. The differences between the ball-hitting points and estimation points became smaller as the number of trials increased, suggesting that at least temporary error detection capability was developed.