## 1 Introduction  
Jump testing has become commonplace for practitioners working in strength and conditioning or sports science [1], with the metrics measured in jump testing used to monitor the efficiency of training programmes [2] or the association with athlete performance (e.g., change of direction speed [3] or linear sprint speed [4, 5]). Studies have utilized the countermovement jump (CMJ) and drop jump (DJ) tests to evaluate slow (i.e., duration \(\geq 250\) milliseconds [ms]) and fast (i.e., duration \(\leq 250\) ms) stretch-shortening cycle (SSC) functions, respectively [6, 7, 8]. Recently, several studies have confirmed that the countermovement rebound jump (CMRJ) provides practitioners with the same reliable metrics as both the CMJ and DJ, and it is more time-efficient for testing, especially when working with large groups of athletes [1, 9]. Aside from jump testing, sprint running is common in many sports; thus, the assessment of sprint speed is understandably considered an essential monitoring tool for various athletic populations [5, 10, 11]. However, unlike track sprinting, where the maximum linear sprint speed is the only determining factor of success, sprint speed could impact matches in a multitude of ways in field- or court-based sports. Specifically, the most common sprint distance for soccer players is, on average, 20 meters (m), highlighting acceleration as being more prevalent than top speed [6; 12; 13]. Furthermore, these short-distance sprints in sports like soccer are interspersed with multi-directional movements, such as the powerful side-step or shuffle, to evade defenders or react to attacking movements [6]. Therefore, the ability to decelerate, change direction, and re-accelerate (or sprint) again has become an essential skill for athletes in field- or court-based sports [14]. This capacity is often referred to as the change of direction (COD) speed. Despite a wide variety of testing options to assess COD speed, the 505 assessment stands out as a widely adopted method due to its capability of evaluating something called the COD deficit (which represents the difference in time between a COD assessment and linear speed assessment of equal total distance), in addition to typical outcome measures of time [15; 16]. It has been proposed that the strength or power capabilities of muscles in the lower extremities evaluated in jump testing are determining factors of linear or COD speed [3]. For this reason, several studies have investigated the association between jump performance (via a range of metrics) and linear or COD speed performance [3; 5; 10; 11; 16; 17]; however, findings show large inconsistencies. For example, when considering the relationship between jumping and linear sprint speed, an inverse correlation between CMJ height and 10 m sprint time (\(r=-0.54\), \(p<0.05\)) has been observed [3], and another study found the same inverse correlation between CMJ height and 30 m (\(r=-0.54\), \(p<0.05\)) as well as 60 m (\(r=-0.55\), \(p<0.05\)) sprint times [5]. However, these two studies recruited healthy males and professional sprinters as their subjects, respectively, which does not guarantee comparable findings in team sport athletes, given the inherent differences in sprint characteristics already noted between these populations [12]. Taking this into consideration, [PERSON] et al. [13] reported a large inverse correlation between CMJ height and 30 m sprint time (\(r=-0.69\), \(p<0.01\)) in Australian Rules football players, and [PERSON] et al. [10] found a very large correlation between CMJ height and 20 m sprint time (\(r=-0.74\), \(p=0.006\)) in first-class county cricketers. When considering the DJ, [PERSON] and [PERSON] [4] reported that DJ height had a large to very large correlation with the 10 m (\(r=-0.66\), \(p<0.005\)) and 30 m (\(r=-0.86\), \(p<0.005\)) sprint times.