Type of participants was a nonsignificant moderator. Similar effects were revealed for students, d ¼ 0.50, 95% CI (0.35, 0.66), beginner athletes, d ¼ 0.47, 95% CI (0.32, 0.62), and more experienced athletes, d ¼ 0.38, 95% CI (0.10, 0.65). This hypothesis was largely based on the assumption that for more experienced athletes it would be harder to improve. However, this was not the case, suggesting that the use of self-talk was effective for all kinds of participants. A possible explanation may be that in most cases researchers implement interventions including training of self-talk when sampling athletes, which proved to increase the effectiveness of self-talk (see results on training in the next section). To increase our confidence in this finding, more studies with experienced athletes should be conducted, because only eight effect sizes involved such athletes in the present investigation.