## 4 Discussion  
The demands of modern sports require high physical performance as well as cognitive skills, which allow one to react and make optimal decisions as fast as possible [42]. The development of technology allows for testing with high accuracy; however, establishing the most appropriate settings is still discussed. Most testing of agility is performed in forward movement, whereas there is a lack of assessment of backward movements in response to stimuli [19]. This can be considered a gap in the literature, and with this study we have tried to fill it. There are currently no agility tests that assess defensive movement (backward) in volleyball. Mainly are assessed tasks considered as offensive actions (forward movement). Therefore, the main aim of the study was to assess the agreement, reliability, accuracy, and validity of the DRAT. Our findings confirmed the excellent quality of the whole test of the defensive reactive agility in top-level, male volleyball players. However, the internal structure presented different levels of quality between components. Specifically, the reliability, accuracy, and validity of the left and right-side slides were good or moderate, respectively, while the back slide presented the lowest values of the validation indices. The consistency between the two DRAT tests had small to medium effects. Total test time and right-side slide had small effects (\(d\) = \(-\)0.05 and \(d\) = 0.17), while the back slide and left-side slide had medium and large effects (\(d\) = 0.35 and \(d\) = \(-\)0.67). There was good agreement for all four variables, with no outliers, and most participants were close to the average difference. This strong agreement is confirmed by low RC values, especially 0.20 for total test time and lower for the other variables. The DRAT test showed excellent reliability in total time (ICC = 0.91). This states a similar value as presented by [PERSON] et al. [56] for the Illinois Agility Test (ICC = 0.96). The mentioned test was performed in a planned manner, and it can be assumed that planned tasks (COD) depend on their durability and complexity characterized by high ICC values [21]. Also, the coefficient of variation is low in planned tasks [57]. This comparison with the typical COD test strengthens our results and indicates the reliability of our test as excellent. In soccer-specific agility tests, the results of ICC were provided as excellent by [PERSON] et al. [58]. However, in this test, only forward movements were considered, which did not totally address the demands of team sports. There is a need to consider backward movement in response to the stimulus, which we did in our study. Some doubt provides results of backward movement where ICC was the lowest; therefore, caution is needed when interpreting these results, and further studies are warranted. Previously [PERSON] et al. [59] validated the reaction time and defensive sliding test (RTADST) in a group of basketball players, which also addressed indicated tasks associated with defensive movements. They also provided high reliability (ICC = 0.86) for the total time of the test, but without analysis of single components. Proposed by [PERSON] et al. [60], the Coimbra reactive agility soccer test (CRAST) also was characterized by high reliability (ICC = 0.95); also, the coefficient of variation was low <10% similar to our study. Generally, the study considers reactive agility ICC range 0.77-0.93, which corresponds to our results [61]. Despite the fact that most analyzed studies consider only two options, in our test, participants had to perform movement in three directions. When considering accuracy (SEM), our test also, in total time, provided the best results, where components were slightly worse. This was despite the study by [PERSON] et al. [62], where the analyzed tennis-specific agility test (TAT) for the total time was worse than in DRAT (0.02 vs. 0.34). Also, low SEM was provided in the Y-agility test, which is considered one of the most popular in reactive agility assessment [63].