Self-Talk in the Swimming Pool: The Effects of Self-Talk on Thought Content and Performance on Water-Polo Tasks

Transcription

1 JOURNAL OF APPLIED SPORT PSYCHOLOGY, 16: , 2004 Copyright Association for Advancement of Applied Sport Psychology ISSN: print / online DOI: / Self-Talk in the Swimming Pool: The Effects of Self-Talk on Thought Content and Performance on Water-Polo Tasks ANTONIS HATZIGEORGIADIS, YANNIS THEODORAKIS, AND NIKOS ZOURBANOS University of Thessaly The present study examined the effect of instructional and motivational self-talk on the occurrence of interfering thoughts and performance on two water-polo tasks with similar characteristics performed in the same environment. Two experiments were conducted in the swimming pool, one involving a precision task (throwing a ball at target) and one involving a power task (throwing a ball for distance). In the first experiment (precision task), both self-talk groups improved their performance in comparison to the baseline measure, with participants using instructional self-talk improving more. In the second experiment (power task), only the motivational self-talk group improved its performance significantly. In both experiments the occurrence of interfering thoughts declined for both groups. The results of the study provide further support for the effectiveness of self-talk and give preliminary evidence regarding likely mechanisms through which self-talk influence performance, that is through indications that self-talk reduces thoughts not related to task execution, thus enhancing concentration to the task. The use of cognitive strategies to improve performance has been a common practice among athletes for many years, however its systematic training has only recently begun and is expanding rapidly. Accordingly, the interest of sport psychologists in researching those techniques and designing mental training programs is growing. One of those techniques that have attracted researchers attention within the last decade is self-talk (ST). ST has been defined as an internal dialogue in which the individuals interpret feelings and perceptions, regulate and change evaluations and cognitions and give themselves instructions and reinforcement (Hackfort & Schwenkmezger, 1993, p. 355). In simple words, ST refers to statements people make to themselves either internally or out-loud. Originally, researchers discriminated between positive and negative ST. Weinberg (1988) describes positive ST as ST that helps athletes to stay focused, not to dwell on past mistakes, or project far in the future. In contrast, negative ST is that which is inappropriate, anxiety producing and counterproductive. More contemporary approaches further discriminate ST in relation to its content. Zinsser, Bunker, and Williams (2001) identified that ST can be characterised as instructional or motivational. Instructional ST refers to statements related to Received 10 September 2002; accepted 20 April We would like to thank Dr. Marios Goudas for his valuable assistance in preparing and revising the manuscript. The financial support of the State Scholarships Foundation of Greece to the first author is gratefully acknowledged. Address correspondence to Antonis Hatzigeorgiadis, Department of Physical Education and Sport, University of Thessaly, Karies, 42100, Trikala, Greece. ahatzi@pe.uth.gr 138

2 SELF-TALK, THOUGHTS AND PERFORMANCE 139 attentional focus, technical information and tactical choices, whereas motivational ST refers to statements related to confidence building, effort input and positive moods. Initial research focused on the effects of positive and negative ST on performance. In field studies results have been equivocal. Some studies found positive and negative ST corresponding to good and poor performances (e.g., Highlen & Bennett, 1983; Van Raalte, Brewer, Rivera, & Petipas, 1994), whereas in others no relationship between direction of ST and quality of performance emerged (e.g., Dagrou, Gauvin, & Halliwell, 1991; Rotella, Gansneder, Ojala, & Billings, 1980; Van Raalte, Cornelius, Brewer, & Hatten, 2000). However, it has to be noticed that in these studies ST was evaluated as content of thoughts and expressions and not as a designed performance strategy. In contrast, experimental research, where ST has been used as a performance improvement strategy employing specific cues, has provided more consistent results regarding the effectiveness of positive ST. In particular, positive ST has been found to have positive effects on performance on experimental tasks involving golf (Johnson-O Connor & Kirschenbaum, 1982), endurance (Weinberg, Smith, Jackson, & Gould, 1984), basketball (Hamilton & Fremour, 1985), skiing (Rushall, Hall, Roux, Sasseville, & Rushall, 1988), and dart throwing (Dagrou, Gauvin, & Halliwell, 1992; Van Raalte et al., 1995). More recently, attempts have been made to investigate the effects of instructional and motivational ST on performance. Ziegler (1987) found that the use of instructional ST by beginners tennis players significantly improved performance on forehand ground strokes. Rushall et al. (1988) reported that instructional and motivational ST improved performance on a ski task, whereas Mallett and Hanrahan (1997) and Landin and Hebert (1999) reported that instructional ST significantly improved performance of elite sprinters and tennis players respectively. Finally, Theodorakis, Chroni, Laparidis, Bebetsos, and Douma (2001) examined the effects of instructional ST on a basketball-shooting task. Appropriate versus inappropriate instructional ST were tested. The results indicated that participants using appropriate ST improved their performance compared to those of the group using inappropriate ST and those of a control group. In relation to the content of ST, instructional ST focuses on technical, tactical or kinaesthetic aspects of task execution, whereas motivational ST aims to increasing effort and selfconfidence and creating positive moods. Subsequently, Theodorakis, Weinberg, Natsis, Douma, and Kazakas (2000) speculated that the effects of ST on performance should depend on the nature of the task to be performed. Instructional ST should be more beneficial for tasks characterised by precision, because the execution of such skills can be aided through increased attentional focus on technical parts of the execution. In contrast, motivational ST should be more beneficial to tasks characterised by strength and endurance, because execution of such skills can be aided through concentration on increased effort. After conducting four experiments involving heterogeneous tasks, they found that for tasks involving fine execution instructional ST was more effective, whereas for tasks requiring gross execution instructional and motivational ST were equally effective. Even though it is documented that ST can be beneficial to performance, no research has attempted to investigate possible mechanisms through which ST affects performance. Nevertheless, several explanations have been put forward. Hardy, Jones, and Gould (1996) proposed that ST may enhance performance through increases in confidence and anxiety control. On a different level, Landin (1994) proposes that the effectiveness of ST is related to attentional processes. The ability to direct attention to task-relevant cues and not be distracted by irrelevant information is recognized as one of the most important keys for successful performance (Singer et al., 1991).

3 140 A. HATZIGEORGIADIS ET AL. The importance of attentional processes has attracted remarkable amount of attention in the test-anxiety literature. According to the cognitive interference theory (Sarason, 1984) and the processing efficiency theory (Eysenck, 1992), interfering thoughts during task execution may have detrimental effects on performance. Gould, Eklund, and Jackson (1992) in a qualitative inquiry reported that distractive thoughts are evident even among elite athletes and relate to impaired performance. Similarly, Hatzigeorgiadis and Biddle (2000, 2001) in quantitative investigations identified that the occurrence of interfering, and in particular worrying, thoughts during sport performance is a regular phenomenon and may be responsible for performance decrements. If ST reduces unnecessary thoughts individuals experience while executing a task, then this can be a likely mechanism through which ST facilitates performance. The examination of this hypothesis, which has not been previously tested, could enhance our understanding of the beneficial effects of ST on performance. Summarizing, the purpose of the present study was to explore whether the use ST may be beneficial to performance through reduction of interfering thoughts. For that reason, the effects of ST on performance and thought content were examined in two experiments. In order to test the effectiveness of motivational versus instructional ST in relation to the requirements of the task, the experiments involved two homogeneous tasks with different motor demands. In particular, the first experiment involved a precision task, which required throwing a water-polo ball at a target, whereas the second involved a power task, which required throwing the ball for distance. EXPERIMENT 1 The first experiment involved throwing a water-polo ball at a target. Three groups were formed, one control and two experimental. One experimental group used instructional ST, whereas the other used motivational ST. We hypothesized that (a) performance of the experimental groups will improve when using ST, (b) because a precision task was used, the instructional ST group will have greater performance improvements than the motivational ST group, and (c) the occurrence of interfering thoughts for the experimental groups will decrease when using ST. Method Participants Sixty swimming class students (30 males and 30 females) with no prior experience in water polo volunteered to participate in the study. Their mean age was 20.7 years (SD = 1.46). In order to ensure that participants could comfortably execute the task, a minimum performance requirement was used, that was hitting the target at least once in the baseline measure. Two participants (one male and one female) were dropped because they did not fulfill the criterion and were replaced. Measures The performance test in this experiment involved hitting a target. Two targets (35 50 cm each) were placed at the top corners of a water-polo post. Participants were asked to perform ten throws, five at each target interchangeably. The total of successful throws was the score for the test. All throws were executed behind a lane on a marked spot opposite to the center of the post. Participants could not stand on their feet (they were treading water) and were not allowed to rest on the lane on the time of the execution. An average of about four out of ten successful

4 SELF-TALK, THOUGHTS AND PERFORMANCE 141 throws was sought for the baseline measurement. After pilot testing the distance for the throw was set at five meters for males and four meters for females. Test retest reliability for the test assessed in the pilot stage was satisfactory (r =.72) For the evaluation of interfering thoughts occurring while performing the task a scale was used based on the Thought Occurrence Questionnaire for Sport (Hatzigeorgiadis & Biddle, 2000). To improve applicability of the instrument for the needs of the experiment appropriate modifications were made based on pilot testing. The scale comprised 12 items (e.g., While executing the task I had thoughts... that I m not performing well,... that I m not good at shooting the target,... about how other people would judge my performance ). Participants were asked to respond on a 5-point scale (1 = never to 5 = often) how frequently during the task they experienced the listed thoughts. Cronbach s alpha coefficients were.84 for the baseline measurement and.78 for the experimental measurement. Procedures All participants were tested twice. On arrival at the swimming pool for the baseline measurement participants were informed about the purposes of the experiment. In particular, they were told that the test involved examination of learning strategies. They were also briefed regarding the requirements of the experiment and after being reassured that data would be confidential, they were asked to sign informed consent and complete a form containing demographic information and information regarding their involvement with sports. Subsequently they were asked to get ready to perform the test and they were allowed five minutes to warm-up in the swimming pool. During warming-up they were not allowed to execute throws. After the warmup they were given instructions regarding the technique of the throw, which were composed after consulting three water-polo coaches, and performed four trial-throws for familiarization with the task. Subsequently, they executed ten experimental throws interchangeably to each target. After completing the task, they were immediately asked to complete the questionnaire evaluating occurrence of interfering thoughts while performing. After completing the test requirements participants were thanked and asked not to discuss with other people about the experiment. The whole procedure lasted approximately 20 minutes for each individual. Two participants were tested at each time, at the opposite ends of the swimming pool. The second testing took place two weeks after the first. During that period participants did not have the chance to practice. In relation to the baseline measurement, participants were divided into three equal performance groups. Subsequently, the three groups were randomly assigned into two experimental and one control condition (N = 20, 10 males and 10 females for each group). The control group repeated the procedures followed in the baseline testing. Similar procedures were used for the experimental groups, which however were told that in order to examine the effectiveness of a learning strategy they would have to use key words before each shot. In order to ensure that the key words were actually said, participants were instructed to speak audibly. The verbal cues were used immediately before each throw. In order to get familiar with the use of ST, participants in the experimental conditions were asked to use the verbal cues for the four trial-throws. One experimental group used motivational ST ( I can ), where as the other used instructional ST ( ball target ). The choice of the cue words was made based on the existing ST literature (e.g., Theodorakis et al., 2000; Van Raalte et al., 1995) and were finalized after consulting three water-polo coaches, who were asked to indicate the most important execution elements for throwing the ball accurately. After completing the task for the second time all groups were again asked to complete the questionnaire assessing the occurrence of interfering thoughts. Participants were once more requested not to discuss about the experiment with other people and were thanked for their participation. The procedure

5 142 A. HATZIGEORGIADIS ET AL. Table 1 Descriptive Statistics for Experiment 1 Performance Cognitive Interference Measure 1 Measure 2 Measure 1 Measure 2 Group N M SD M SD M SD M SD Total Control Instructional ST Motivational ST Number of successful throws. again lasted approximately 20 minutes for each participant. Two participants assigned to the same condition were tested at each time. Results Descriptive statistics are presented in Table 1. One-way ANOVA revealed that there were no significant differences in performance between the three groups for the baseline measure, F(2, 57) = 0.03, p =.97. Subsequently, a 2 3 (Trial Group) repeated measures ANOVA was used to test for differences between the first and the second measure for the three groups. The results revealed a significant trial by group interaction effect, F(2, 57) = 5.40, p <.01, η 2 =.16. Mean scores for the three groups in the first and the second session are presented in Table 1. The interaction effect is visible in Figure 1. Paired sample t-tests indicated that while there were no differences between the first and the second measure for the control group, t(19) = 0.91, p =.37, significant differences emerged for the instructional ST group Number of Successful Throws 5,5 5 4,5 4 3,5 3 control instructional motivational Baseline Assessment Experimental Figure 1. Experiment 1: Performance in baseline and experimental assessments for the three groups.

6 SELF-TALK, THOUGHTS AND PERFORMANCE 143 t(19) = 3.28, p <.01, and the motivational ST group, t(19) = 2.96, p <.01. For both experimental groups performance improved. Estimation of effect sizes (Cohen, 1977) for the second trial revealed a large effect between the control and the instructional ST group (d = 1.39) and a large effect between the control and the motivational ST group (d =.99). Furthermore, a small effect was detected between the instructional and the motivational ST group in favor of the first (d =.24). Similar analyses were performed regarding the occurrence of interfering thoughts. A 2 3 (Trial Group) repeated measures ANOVA revealed significant trial by group interaction effect, F(2, 57) = 5.72, p <.01, η 2 =.17. Mean scores for the three groups in the first and second trial are presented in Table 1. Visual representation of the interaction effect is displayed in Figure 2. Paired sample t-tests indicated that while there were no differences between the first and the second measure for the control group, t(19) = 0.94, p =.36, significant differences emerged for the instructional ST group, t(19) = 4.07, p <.01, and the motivational ST group, t(19) = 3.79, p <.01. For both groups frequency of interfering thoughts dropped. Estimation of effect sizes for the second trial revealed a moderate to large effect between the control and the instructional ST group (d =.77) and a moderate effect between the control and the motivational ST group (d =.57). In order to further examine the association between decreases in interfering thoughts and performance improvement, the correlation between changes in frequency of interfering thoughts and changes in performance (scores in the experimental measurement minus scores in the baseline measurement) was calculated. The analysis revealed a moderate negative relationship (r =.48, p <.01), indicating that the reduction of interfering thoughts related to increases in performance. Overall, the results of this experiment supported the predictions. In accordance with the first hypothesis, both experimental groups improved their performance in relation to the control group, thus providing support for the effectiveness of ST as a performance enhancing strategy. Furthermore, in line with the second hypothesis, the instructional ST group showed a higher improvement than the motivational ST group, suggesting that instructional ST should be more 2,8 2,6 TOQS score 2,4 2,2 2 control instructional motivational Baseline Assessment Experimental Figure 2. Experiment 1: Cognitive interference in baseline and experimental assessments for the three groups.

7 144 A. HATZIGEORGIADIS ET AL. appropriate for tasks involving precision. Finally, in accordance to the third hypothesis, frequency of interfering thoughts decreased for both experimental groups, indicating that the use of ST can possibly help performers concentrating better to the task at hand, thus enhancing performance. EXPERIMENT 2 The second experiment involved throwing a water-polo ball for distance. Once again, one control group and two experimental (instructional ST and motivational ST) were contrasted. We hypothesized that (a) performance of the experimental groups will improve when using ST, (b) because a power task was tested, the motivational ST group will have greater performance improvements than the instructional ST group, and (c) the occurrence of interfering thoughts for the experimental groups will decrease when using ST. Method Participants Sixty swimming class students (30 males and 30 females, not participating in the first experiment) with no prior experience in water-polo participated in the second study. Their mean age was 20.5 years (SD = 1.33). A minimum performance requirement was used, that was being within two standard deviations of the mean score (separately for males and females). Three participants (one male and two females) were dropped because they did not fulfill the criterion and were replaced. Measures The performance test in this experiment involved distance throwing. Participants were placed before a rope tied between two lanes and were asked to perform ten throws. As in the previous experiment, participants could not stand on their feet and were not allowed to rest on the lane on the time of the execution. Distance was measured using a tape from the middle of the rope to the point were the ball was landing each time. The exact spot of the landing was spotted by two trained research assistants (able swimmers) who were also in the water, near the area where the ball was landing during the familiarization throws. The distance of each throw was measured by these research assistants and was spelled out to another assistant standing at the side of the pool. Each participant s throws were measured by the same research assistant. The average of the ten throws was the score for the test. Test retest reliability in pilot testing was satisfactory (r =.90). The questionnaire described in experiment one was used to assess occurrence of interfering thoughts. Cronbach s alpha coefficients were.85 for the baseline measurement and.81 for the experimental measurement. Procedures Similar procedures to those in experiment one were followed. Before executing the task, instructions regarding the technique of the throw were given to all participants. These instructions were composed after consulting three water-polo coaches, who were asked to indicate what are the most crucial execution elements for throwing the ball at greatest distance. The verbal cues were used immediately before each throw. The key word for the motivational ST group was the same as in experiment one ( I can ). For the instructional ST group the key words were adjusted to the task ( elbow hand ; corresponding to the instructions elbow high, hand follow the ball ). The choice of cue-words was again based on the existing ST

8 SELF-TALK, THOUGHTS AND PERFORMANCE 145 Table 2 Descriptive Statistics for Experiment 2 Performance Cognitive Interference Measure 1 Measure 2 Measure 1 Measure 2 Group N M SD M SD M SD M SD Total Control Instructional ST Motivational ST Meters. literature (e.g., Theodorakis et al., 2000; Van Raalte et al., 1995) and instructions from three water-polo coaches. Results Descriptive statistics are presented in Table 2. Similar analyses to those in experiment one were calculated. One-way ANOVA revealed that there were no significant differences in performance between the three groups for the baseline measure, F(2, 57) = 0.01, p =.99. A2 3 (Trial Group) repeated measures ANOVA revealed a significant trial by group interaction effect, F(2, 57) = 5.65, p <.01, η 2 =.17. Mean scores for the three groups in the first and the second measure are presented in Table 2. Visual representation of the interaction effect is displayed in Figure 3. Paired sample t-tests indicated that there were no significant differences between the first and the second measure for the control group, 12,2 11,9 control instructional motivational Meters 11,6 11,3 11 Baseline Experimental Assessment Figure 3. Experiment 2: Performance in baseline and experimental assessments for the three groups.

9 146 A. HATZIGEORGIADIS ET AL. t(19) = 0.11, p =.91, but also for the instructional ST group, t(19) = 1.65, p =.11. In contrast, significant differences emerged for the motivational ST group, t(19) = 5.02, p <.01. In particular, performance for the motivational ST group improved. Cohen s (1977) effect size index revealed a small effect between the control and the motivational ST group (d =.20). Furthermore, there was a small effect between the motivational with the instructional ST group (d =.16). A 2 3 (Trial Group) repeated measures ANOVA for interfering thoughts revealed significant trial by group interaction effect, F(2, 57) = 6.53, p <.01, η 2 =.19. Mean scores for the three groups in the first and second trial are presented in Table 2. The interaction effect is presented in Figure 4. Paired sample t-tests indicated that while there were no differences between the first and the second measure for the control group, t(19) = 0.67, p =.51, significant differences emerged for the instructional ST group, t(19) = 2.66, p <.01, and the motivational ST group, t(19) = 5.14, p <.01. For both experimental groups occurrence of interfering thoughts deteriorated. Estimation of effect sizes for the second trial revealed a moderate effect between the control and the experimental ST groups (d =.54). Examination of the correlation between changes in frequency of interfering thoughts and changes in performance revealed a negative relationship, which however was rather small and non significant (r =.20, p =.12). Overall, the results of this experiment provided support for two of the three predictions. In particular, the first hypothesis was not fully supported. Performance of the motivational ST group improved, however there was no improvement for the performance of the instructional ST group. Subsequently, the second hypothesis was supported, providing further evidence that the type of ST in relation to the nature of the task is crucial for its effectiveness. Finally, regarding the third hypothesis, similarly to the first experiment the use of ST decreased the frequency of interfering thoughts participants reported having during task execution. 2,8 2,6 TOQS score 2,4 2,2 2 control instructional motivational Baseline Experimental Assessment Figure 4. Experiment 2: Cognitive interference in baseline and experimental assessments for the three groups.

10 SELF-TALK, THOUGHTS AND PERFORMANCE 147 DISCUSSION The study examined the effects of ST on thought content and performance on water-polo tasks. Two experiments were conducted involving one precision task and one power task. Two different types of ST, namely instructional and motivational were used. In brief, the results showed that ST reduced the occurrence of interfering thoughts during execution and that depending on the combination of ST and task, ST can be helpful to performance. Self-Talk Type and Performance Instructional ST enhanced performance in the precision task. Similar results for the effectiveness of instructional ST on execution of fine skills were reported by Ziegler (1987) who found that the use of instructional ST significantly improved performance on forehand and backhand ground strokes in beginner tennis players and also by Landin and Hebert (1999) who reported improved volleying performance in elite tennis players. In contrast, performance of the instructional ST group did not improve for the power task. In a study examining the effectiveness of instructional ST on a gross skill, Mallett and Hanrahan (1997) experimented with 100-meters sprinters. Different ST cues corresponding to different segments of the race were used and results revealed significant performance improvements. We expected that instructional ST would facilitate performance to a greater degree for the precision task, compared to the power task, and that was confirmed, however, we speculated that performance for the power task would also improve, which did not. A likely explanation is that by focusing on the correct technical execution of the throw, the element of strength for throwing the ball for distance was undermined by participants, indicating that instructional ST might have not been appropriate for this power task. Motivational ST improved performance in both tasks. Even though early research did not discriminate between instructional and motivational ST, studies examining the effects of positive ST on performance could be in many cases characterized as examining effects of motivational ST, since the ST content is comparable. Thus, the beneficial effects of motivational ST on performance are evident in the literature for both fine (e.g., Hamilton & Fremour, 1985; Rushall et al., 1988) and gross (e.g., Weinberg et al., 1984) tasks. However, in these studies there were no comparisons of effects on tasks with different demands. We expected that motivational ST would facilitate performance in both tasks, however, we also speculated that performance for the power task would improve more compared to that for the precision task, which was not confirmed. Attempting to interpret these results, it can be speculated that the input of effort and the sense of confidence underlined by ST in these experiments was equally important for the two tasks and at the same time did not undermine the quality of the execution. A similar study, comparing the effects of instructional and motivational ST on performance, was conducted by Theodorakis et al. (2000). Even though in the above mentioned investigation participants were asked to repeat the experimental tasks six times, it is interesting to compare the results of the two studies. In brief, they found that instructional ST improved performance in both fine and gross tasks, whereas motivational ST improved performance only for the gross tasks. The differences in the results between the two studies could be attributed to the differences between the nature of the tasks that were used. In that study, in order to compare effects of ST on tasks with different motor demands, four tasks with totally different characteristics (soccer passing accuracy, badminton serving accuracy, sit-ups, knee extensions) were used. In contrast, the present study focused on tasks having a common element (throwing a ball), performed in the same environment (swimming pool), which however differed in terms of

11 148 A. HATZIGEORGIADIS ET AL. motor requirements (precision vs. power). Thus, one suggestion that can be made is that differences in the effectiveness of ST could be attributed to the precise characteristics of the performed task in relation to the execution-elements highlighted by the type and content of ST. The importance of appropriately matching ST to the task has been identified by Landin (1994), who notices that the effectiveness of ST depends on several factors such as brevity, accuracy, and the nature of the task. The appropriateness of ST in relation to the demands of the task is crucial for achieving performance improvement. Thus, it can be argued that the relative significance of the task-element highlighted by ST to performance is crucial in determining how effective the use of ST can be for each task. The results of the present study provide further support for the differential effects of ST on performance depending on the combination of ST with the demands of the task. Self-Talk and Reduction of Interfering Thoughts The study also examined whether the use of ST decreased frequency of interfering thoughts during task performance. In all experimental groups participants reported less interfering thoughts when using ST, compared to the baseline measure when ST was not used. Landin (1994) suggested that the effectiveness of ST is related to attentional processes. Sarason (1984) suggested that interfering thoughts have the effect of lessening the individual s effective behavior by diverting attention from task relevant cues and using cognitive resources which otherwise could be used for task-processing activities. Furthermore, Eysenck (1992) postulates that worrying thoughts, such as those reported from the participants in the study, limit processing efficiency. In the sport context, Gould et al. (1992) used qualitative methods of inquiry to examine relationships between thought content and performance in elite wrestlers. Successful performances were characterised by absence of thoughts for some of the athletes, while others reported their only thoughts to be related to focusing on strategies and techniques that should be applied. In contrast, during unsuccessful performances athletes admitted having thoughts that were not related to the task, as well as self-defeating negative thoughts. Similar results have been reported by Hatzigeorgiadis and Biddle (2001). In a study examining perceived effects of interfering thoughts on performance they reported that the occurrence of interfering thoughts during volleyball performance negatively affected athletes concentration. Drawing from the above propositions, it can be argued that if the use of ST reduces interfering thoughts, then it is possible that this is one of the mechanisms through which ST is helpful to performance. In the present investigation it was revealed that participants reported fewer interfering thoughts when using ST. It could be argued that reduction of interfering, and in particular worrying, thoughts might be a result of improved performance and was not due to the use of ST. However, the fact that interfering thoughts were reduced even for the instructional ST group in the second experiment, where performance was not improved, seems to provide support for our argument. In particular, it could be speculated that the use of ST per se reduces interfering thoughts regardless of its effectiveness, which depends also on the appropriateness of the selected verbal cues. This argument seems to be further justified from the correlational analysis regarding the changes in interfering thoughts and changes in performance, which revealed a moderate relationship in the first experiment but a small one in the second, where performance of the instructional ST group did not improve. Thus, the results of the present study give preliminary evidence that the use of ST facilitates performance through reducing interfering thoughts and thus enhancing concentration to the task.

12 SELF-TALK, THOUGHTS AND PERFORMANCE 149 A limitation that should be acknowledged regarding the implementation of this study is the use of single baseline and experimental assessments. The use of multiple assessments is warranted in order to ensure that performance scores can be confidently trusted. However, the nature of the experiment did not allow for multiple assessments. In particular, there were two reasons that imposed the choice of single assessments. The first was the duration of the experimental procedures. As described in the methods participants were tested in pairs. The experimental task lasted approximately 20 minutes for each pair, which meant that an overall of 30 minutes were required for each testing (including waiting time for participants to start simultaneously and allowing time for the research team to file participants and prepare). Choosing multiple baseline/experimental assessments would mean that the already extended schedule of the experiment should be multiplied. The second reason was that the procedures were tiring for participants. Attempting multiple assessments in single sessions would mean that participants should get in and out of the water several times in each session, which is rather exhausting. Furthermore, choosing multiple sessions could have resulted in raised withdrawal rates due to fatigue or boredom. Therefore, the choice of single assessments was preferred. In order to counterbalance possible effects participants were required to execute ten throws for each assessment, which was considered an adequate number of attempts in order to obtain safe indications of performance. Furthermore, considering that the effectiveness of ST in experimental tasks has been rather consistently supported in the literature (e.g., Landin & Hebert, 1999; Mallett & Hanrahan,1997; Theodorakis et al., 2000), the key question in this investigation became whether performance increases can be attributed to the reduction of interfering thoughts individuals experience during task execution. The results of both studies supported this hypothesis, thus enriching research findings in the ST literature. Overall, the results of the study support previous findings regarding the effectiveness of ST on task performance, highlighting the importance of matching ST with the demands of the task to be performed, even when tasks with similar characteristics are performed. Furthermore, and most importantly, it identifies a likely mechanism through which ST may facilitate performance that is the reduction of interfering thoughts during task execution. In practice, two key implications can be identified. First, ST can be used to direct attention and prevent lapses of concentration, thus enhancing performance. Given the effectiveness of ST, its use should be encouraged and practiced by trainers and coaches. Second, the selection of appropriate cues is crucial for the effective use of ST. In order to maximize effectiveness, the cues should be carefully selected in relation to the demands of the task and the needs of the individual. Thus, it is important to identify the elements of task execution that need to be highlighted and accordingly design and adjust ST cues. Further research is warranted to examine personal and situational parameters that should be considered in order to apply appropriate ST cues. Finally, further exploration of likely mechanisms through which ST affects performance will enhance our understanding of the phenomenon and improve effectiveness of ST strategies. REFERENCES Cohen, J. (1977). Statistical power analysis for the behavioral sciences. New York: Academic Press. Dagrou, E., Gauvin, L., & Halliwell, W. (1991). La preparation mentale des athletes Ivoiriens: Pratiques courantes de perspectives de recherche [Mental preparation of Ivory Coast athletes: Current practice and research perspective]. International Journal of Sport Psychology, 22, Dagrou, E., Gauvin, L., & Halliwell, W. (1992). Effets de langage positif, negatif et neuter sur la performance motrice [Effects of positive, negative and neutral self-talk on motor performance]. Canadian Journal of Sport Science, 17, Eysenck, M. W. (1992). Anxiety: The cognitive perspective. Hove, UK: Erlbaum.

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