## 1 Introduction
The reliability concept refers to the reproducibility of measurements in test-retest trials involving the same subjects [16; 17]. Usually, it is examined according to both absolute and relative reliability. The first one is evidenced through the analysis of the typical measurement error (i.e., within-subject variation in repeated trials), whereas the latter is examined according to the stability and maintenance of an individual's ranking relative to others in the group after multiple test-retest assessments [18]. Most frequently, it is represented by the interclass correlation coefficient (ICC). Greater reliability suggests better test accuracy and the potential to detect performance changes over time [17; 19]. Test sensitivity reflects the measurement's ability to detect a small, but practically significant, change in performance [19]. It is established by comparing the smallest worthwhile change (SWC) and the typical error (TE) of the measurement. A higher SWC than TE implies better test sensitivity [19]. The validity of a test refers to how well it measures what it is intended to measure [16]. There are different types of validity, including face validity, which measures how well a test logically assesses the ability it aims to measure. For example, in the current study, face validity was established by simulating bandy sprints. Content validity, on the other hand, can be measured by statistical analysis that identifies the relationship between kinematic parameters in different sprint phases. This concept is based on the idea that the spatiotemporal parameters of skating are task dependent, that is to say, they change with an increase in skating speed from acceleration to the steady-state phase [15]. The lack of a relationship between the spatiotemporal metrics obtained during the two phases would indicate that spatiotemporal data could be used to provide independent information for the different skating phases. Predictive validity is another important type of validity that is often demonstrated by how sport-specific outcomes (e.g., skating kinematics) can predict sports performance (e.g., skating maximal velocity) [20]. However, it generally receives little attention in research [21]. We are not aware of any other investigations that have reported on the reliability and sensitivity of spatiotemporal data obtained by IMUs during skating sprints. On the other hand, several studies have reported these measurement metrics on spatiotemporal parameters in running [22; 23; 24; 25]. However, due to differences in the kinematics between running and skating, caused by the different frictional characteristics of the surfaces on which they are performed, it is not appropriate to translate IMU-derived spatiotemporal data obtained in running to make conclusions about skating. For instance, sprinters try to shorten the ground contact time (\(\approx\)0.08-0.10 s) during the maximum speed phase, which is not the case in skating, where a longer gliding phase (e.g., contact time \(\approx\) 0.32-0.35 s) is required to achieve and maintain the maximum speed. Moreover, although the concurrent (i.e., reference) validity of spatiotemporal parameters obtained by IMUs has been extensively studied both in running [11; 26; 27; 28; 29] and skating [7; 13; 30] activities, less is known about their content and predictive validity. Therefore, this study aimed to investigate the reliability, validity, and sensitivity of spatiotemporal parameters of sprint skating in bandy using two skate-mounted IMUs. Based on the previous validity studies in ice hockey and speed skating that showed a high level of accuracy concerning the IMUs used [7; 13; 30], we hypothesized that spatiotemporal parameters would also show acceptable sensitivity and reliability when observed in well-trained bandy players. Moreover, we hypothesized that the spatiotemporal data would show a low percentage of shared variance when observed separately during the acceleration and steady-state phases.