## 4 Discussion  
The present study investigated the test-retest reproducibility of dynamic balance tests on chronic stroke survivors. In this study, the test-retest reliability of the F8 WT had an ICC = 0.98, similar to the result of an ICC = 0.97 reported in a previous study [14]. Although their test-retest reliabilities were not reported in other studies, the ICCs of the FSST and ST (more affected and less affected sides) in the present study were 0.99, and 0.95 and 0.93, respectively. The test-retest reliability of the F8 WT had an ICC = 0.98, similar to the result of an ICC = 0.97 reported in a previous study [14]. Although their test-retest reliability was not reported in other studies, the  
respectively. All three tests for dynamic balance assessed in this study were found to have an excellent test-retest reproducibility. Since ICC does not indicate the level of measurement error, it cannot interpret the influence of diversity between subjects [23]. In addition, there are limitations to using ICC to explain reproducibility, as there is the issue of the learning effect when ICC is measured repeatedly [6]. SEM and SRD estimate the size of the random measurement error caused by chance variation in the score change that occurs when the same test is repeatedly measured. Additionally, they are used to determine if the measured value is systematically kept constant within a 95% confidence level [5; 9]. Furthermore, SEM is a meaningful statistical value that can estimate changes in the test scores in cohort studies [8]. The SEMs and SRDs of the F8 WT, FSST, and ST have not been reported in previous studies. In the present study, the SEMs of the F8 WT, FSST, and ST (more affected and less affected sides) were 2.21, 2.25, and 0.68 and 0.70, respectively, which were all \(<\)10% [19]. Thus, the SEM values of the dynamic balance tests in the present study were determined to be within reasonable levels. This indicates that the F8 WT, FSST, and ST are sensitive assessment tools that can determine the actual change in the dynamic balance of chronic stroke survivors. SRD is an important index for clinicians to determine the degree to which subjects can change (improvement or worsening), with a 95% confidence interval [7; 10]. The results of this study showed that the SRDs were 6.10, 6.21, and 1.87 and 1.93 for the F8 WT, FSST, and ST (more affected and less affected sides), respectively. Acceptable results were found to be \(<\)20% of the highest score [20]. SRD was used to determine whether the subject change was statistically significant [10]. According to the results of this study, the SRD was not affected by measurement error and chance variation, and the actual subjects' F8 WTs and FSSTs could be significantly improved by approximately 6 s or less, while the ST (more affected and less affected sides) could be improved by approximately two points or more. In addition, since there was no significant distinction in the mean difference between the F8 WT, FSST, and ST, no systematic error was found between the test-retests. Moreover, the SRDs (%) were 28.9% and 21.9% for the F8 WT and FSST, respectively, and for the ST (more affected and less affected sides), they were 27.32% and 24.43%, respectively. The level of measurement error was acceptable [22]. In this study, the F8 WT, FSST, and ST were visualized using the Bland-Altman method to estimate the magnitude of the inter-rater agreement [17]. In the limits of the agreement range, the F8 WT was 9.72 (\(-\)4.59-5.13), FSST was 9.24 (\(-\)4.08-5.16), and ST (more affected and less affected sides) was 3.56 (\(-\)1.99-1.57) and 3.84 (\(-\)2.15-1.69), respectively. The variation (range of error) in the mean difference between the tests was acceptable. This implies that the difference between the mean value and means between examiners were not related, and there was no systematic error as it existed in the 95% confidence interval [24]. The F8 WT, FSST, and ST were found to have a high reproducibility for the dynamic balance measurements of chronic stroke survivors.