The aim of this study is to investigate errorful and errorless training methods on detecting error in tracking task. 24 students of Allameh Tabataba'i University (23± 2.8 yrs.) were randomly selected to perform a computerized tracking test. The participants underwent a pre-test after being given verbal instructions and were divided into two groups of errorful and errorless training according to the test results. The errorless training group, during task performance, saw the target path and the path they were tracking as a diagram and detected errors according to the difference between the two paths. But the errorful training group completed the task goal by trial-and-error. Each group underwent 30 tests in 3 separate sessions with a recovery period of 24 h inbetween. The results showed the significant effect of errorful and errorless training on the progress of detecting errors in acquisition and retention stages of tracking task. Furthermore, a significant difference has been identified between the effects of errorful and errorless training methods on the acquisition and retention of tracking task. This difference was in favor of the errorless training group and this group's progress in detecting errors was more than the errorful training group. The results showed that in addition to the influence of errorful and errorless training methods on detecting error in tracking task, there is a difference between t he effect of these methods in detecting error and the errorless training method has a more positive effect on participants' error detecting ability in the tracking task.

The research aimed to examine the role of lyrics in music on perceived exertion of male and female students during physical activity (running on treadmill). For this purpose, 23 (11 males, 12 females) were selected randomly among volunteered students. The participants underwent physical activity under condition of lyrics music in the first session, same no-lyrics music in the second session and no music in the third session. The test duration was 5 minutes for all participants and their running intensity was in correspondence with 80% of their maximum heart rate. The recovery period between each session was 48 hrs. After each session, the participants specified their rated perceived exertion (RPE) by completing the Borg scale questionnaire. The results of ANOVA revealed that lyrics music had a significant effect on the participants' perceived exertion, but no-lyrics music had no effect on their perceived exertion. With regard to reduction of the perceived exertion rate during the use of lyrics music, it can be concluded that the presence of lyrics in music reduces the participants' perceived exertion and causes the activity time to seem shorter. It can be deduced that the presence of lyrics in music has a significant effect on the improvement of psychological conditions of athletes and their perceived exertion.