Introduction

Mindfulness, which originates from Eastern meditation practices, is recognized as an effective tool for managing anxiety and stress. This approach focuses on increasing awareness in the present moment and non-judgmentally accepting both internal and external thoughts, emotions, and experiences. In competitive sports, where anxiety, psychological pressure, and stress can significantly impact athletes' performance, mindfulness-based interventions have gained significant attention as an effective and novel approach. This method not only helps reduce competitive anxiety and improve focus, but also directly enhances self-awareness and emotional regulation. Global scientific studies have provided substantial evidence of the effectiveness of mindfulness-based interventions in enhancing performance and reducing competitive stress. However, in Iran, particularly in the context of competitive sports, research in this area is still limited. Studies conducted between 2017 and 2024 in Iran have investigated the effects of mindfulness on athletes’ mental health and performance, but these studies have not been fully integrated and require more comprehensive and comparative analysis.

In this regard, meta-analysis as an efficient research method can offer a more conclusive and thorough evaluation of the effects of mindfulness-based treatments on Iranian athletes. Meta-analysis can help identify common patterns and trends in the effectiveness of these methods in reducing competitive anxiety and improving performance, ultimately providing strong scientific evidence for informed decision-making in sports psychology. This meta-analysis aims to systematically review the existing studies on the impact of mindfulness-based interventions on competitive anxiety in Iranian athletes. By collecting and reviewing these studies, this research seeks to aggregate relevant scientific evidence and propose effective strategies for designing psychological interventions to reduce competitive anxiety and improve athletic performance.

Furthermore, meta-analysis can assist sports psychologists in designing optimized interventions to improve mental health and the quality of competitions. The findings of this study can directly impact the design and enhancement of educational and training programs within Iranian sports environments. Moreover, this research can help Iranian athletes gain a better understanding of the positive effects of mindfulness, applying more effective techniques to reduce competitive anxiety and improve focus. Ultimately, answering whether mindfulness-based interventions can effectively reduce competitive anxiety in Iranian athletes could guide the design of new, scientifically validated interventions to improve athletic performance and mental health. Additionally, this meta-analysis serves as an essential tool for gaining a deeper understanding of the impacts of psychological treatments on Iranian athletes and can contribute to the advancement of scientific and practical aspects of sports psychology in Iran and similar countries.

Materials and Methods: This research was conducted in accordance with the guidelines provided by the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P)" and the "Cochrane Handbook for Systematic Reviews." In this study, the meta-analysis method was employed based on the research objectives. Meta-analysis refers to statistical analyses conducted to combine the quantitative findings of a set of studies

Study Scope

The scope of this study includes research conducted in the field of the effectiveness of mindfulness-based interventions on competitive anxiety in athletes during the years 2017 to 2024 in Iran. These studies must meet the necessary methodological criteria. For identifying relevant studies, reputable databases such as Noormags, Magiran, the Comprehensive Portal of Humanities, ScienceNet, Civilica, Jihad University, and IranDoc were used. To select the initial studies, relevant keywords were identified based on the literature review. The keywords used were: "mindfulness," "mindfulness intervention," "mindfulness-based therapy," "mindfulness protocol," "competitive anxiety," "athletes' competitive anxiety," "mindfulness and competitive anxiety," "mindfulness and athletes."

Inclusion and Exclusion Criteria

To be included in this review, studies must meet the following criteria:

• Examining the effectiveness of mindfulness-based therapy on competitive anxiety in athletes.
• Published in Persian.
• Studies must be accessible as full-text articles or theses online.
• Must have been officially published as peer-reviewed articles or theses. Unpublished studies, books, book chapters, and conference abstracts are excluded.
• Studies must provide sufficient data to calculate effect size.
• Studies must be experimental or quasi-experimental.
• Use of valid and reliable instruments.
• Studies must meet necessary methodological conditions (including hypothesis formulation, research method, population, sample size, sampling method, measurement tools, validity and reliability, statistical hypotheses, statistical analysis methods, and correct statistical calculations).

Studies that did not report necessary data for effect size calculation or were exact repetitions of other studies were excluded.

Study Selection

A researcher independently searched electronic databases, gathered potential studies, and organized them based on predetermined eligibility criteria. Duplicate studies were removed. The initial screening process involved reviewing titles and abstracts. Any ambiguities were resolved by a second researcher, who conducted a detailed evaluation of the studies. Studies meeting the inclusion criteria were selected through discussion and consensus within the research team. Relevant details were documented, and key findings were summarized.

Data Extraction

For each study that met the inclusion criteria, the following data were extracted:

• Authors and publication year.
• Study methodology.
• Sample characteristics, including details such as sample size, gender distribution, type of sport activity, average age, average activity duration, education level, ethnicity, and location.
• Instruments used to measure competitive anxiety and the mindfulness treatment protocol.

To calculate effect sizes, the first author computed the effect size for each study included in the meta-analysis. Additionally, other specific data, such as sample size, p-value, standard deviation, pre-test and post-test means for experimental and control groups, and 95% confidence intervals, were accurately entered into the software for more precise analysis.

Quality Assessment

The quality of the included studies was assessed using the risk of bias tool from the CMA2 software. A researcher independently evaluated the quality of each study, and disagreements were resolved by a second researcher. Various aspects, including the study objectives, clarity in describing participant selection criteria, sample size adequacy, handling of missing data, and adherence to ethical considerations, were assessed.

Data Analysis

In this study, effect sizes and subsequent statistical activities were computed using the CMA2 software and the Hedges' g index. Both Hedges' g and Cohen's d calculate effects under the assumption of equal variances, but Hedges' g provides a better estimate by using (n-1) for each sample. Particularly in small samples, Hedges' g is a more accurate index than Cohen's d (Hedges, 1981).

To assess heterogeneity among studies, Tau2, I², and Cochran's Q statistics were used. I² values of 25%, 50%, and 75% were considered to indicate low, moderate, and high heterogeneity, respectively. Depending on the level of heterogeneity, either random-effects or fixed-effects meta-analyses were conducted. Specifically, when heterogeneity was greater than 50%, random-effects meta-analyses were used, while fixed-effects meta-analyses were used when heterogeneity was less than 50%.

Results: Initially, a total of 90 records were reviewed. After excluding 20 studies based on title, 70 articles remained. A full evaluation was conducted for the remaining 70 articles to assess their suitability for inclusion in the study. Ultimately, 10 studies met all the inclusion criteria. The remaining studies were excluded for the following reasons: 21 studies did not meet the inclusion criteria, such as appropriate scientific content and journal credibility; 30 studies had incomplete methodological information; and 9 studies were excluded due to statistical flaws or the absence of sufficient data to report effect sizes. The final sample for the meta-analysis included a total of 283 participants, with the number of individuals in each study ranging from 17 to 40. Participants in all studies included both male and female individuals. Geographically, all studies were conducted in Iran. Regarding the instruments used, the Competitive State Anxiety Inventory (CSAI-2) was employed in all 10 studies.

To examine publication bias in the studies, a funnel plot and statistical index (fail-safe number) were used. The results of the funnel plot (Figure 1) indicate that the overall pattern of effect sizes is acceptable, and there is no significant bias in the studies. In other words, the plot is relatively symmetrical, with no extreme or outlying effect sizes observed. All effect sizes were within the range of 0 and -3.

"The results indicated that to eliminate the obtained significance level in the study (reaching the alpha significance level), an additional 237 studies would need to be considered, which suggests that there is no publication bias in these studies. In other words, after the addition of 237 more studies, the estimated effect sizes would become non-significant." The observed effect size ranged from -0.086 to -1.647. In this study, the effect size of all 10 studies was significant (P<0.05). The combined effect size in the fixed-effects model was -1.275, and for the random-effects model, it was -1.319 (P<0.05). According to Cohen's (1988) criteria, effect sizes greater than 0.8 are considered large and have high clinical significance.

The above figure is the forest plot of the studies included in the meta-analysis. This plot displays the combined effect sizes of each study using the fixed-effects model, and it also shows the deviation and error of each study from the overall combined effect size. Additionally, heterogeneity among the studies was assessed using the Tau², I², and Cochran’s Q statistics. As can be seen, the value of the Q statistic for 10 effect sizes with 9 degrees of freedom was found to be 15.419, which is not statistically significant. The significance of the Q statistic indicates the presence of heterogeneity in the effect sizes of the primary studies. Since the Q value was not statistically significant, it means that no significant heterogeneity in the effect sizes of the studies was observed. This suggests that most of the studies yielded similar results regarding the effect of mindfulness-based interventions on competitive anxiety. Another index used to assess heterogeneity is the I² statistic, which ranges from 0% to 100% and represents the percentage of variability in effect sizes attributable to real differences between studies. The I² value indicates that 41.631% of the variability in the effect sizes of the primary studies is due to real differences, based on the criteria of Higgins et al. (29). This suggests moderate heterogeneity among the primary studies. In other words, approximately 41.6% of the differences in effect sizes are attributed to various factors such as specific features of each study or methodological differences between them.Therefore, the fixed-effects model was chosen for the meta-analysis, and the combined effect size was considered to be -1.275.

Conclusion: This meta-analysis, for the first time in Iran, calculated the effect size of the mindfulness-based intervention variable on competitive anxiety, aiming to provide a comprehensive quantitative synthesis of recent research in this field. To achieve this, data from 10 studies were collected and recorded in a meta-analysis worksheet. The data were analyzed using the CMA2 software. The average effect size was found to be -1.275. According to Cohen's criteria for interpreting effect sizes, this value is considered large. Additionally, the z-value for the studies was -9.721, which is statistically significant at the 0.001 level. Therefore, it can be concluded that, in general, mindfulness training has had a significant impact on competitive anxiety, as measured in the studies included in this meta-analysis.

The results of this meta-analysis align with previous theoretical and empirical foundations, confirming the effectiveness of mindfulness-based interventions in reducing competitive anxiety among athletes. Therefore, mindfulness-based therapy can be widely utilized as an effective method in sports psychology programs to enhance athletic performance and reduce competitive anxiety.

Keywords: Meta-analysis, competitive anxiety, mindfulness, athletes

Ethical Considerations

Compliance with ethical guidelines

All the primary studies included in this meta-analysis were ethically approved and conducted in compliance with ethical research guidelines and protocols.

Funding

This research did not receive any financial support or funding.

Authors' contribution

All authors equally contributed to the design of the study, data collection, analysis, and writing of the manuscript.

Conflict of interest

The authors declared no conflicts of interest regarding this research.