## 1 Introduction
In the same study, the reactive strength index (RSI, a ratio between jump height [JH] and ground contact time [GCT]), reported a moderate to large correlation with the 10 m (\(r=-0.57\), \(p<0.005\)) and 30 m (\(r=-0.42\), \(p<0.005\)) sprint times. Noting that the RSI comprises two component parts rather than a single metric, any changes in DJ height or GCT would distort RSI values [2], which, in turn, explains the reduced correlation between the RSI and sprint time compared to correlations between DJ height and sprint time. Since the CMRJ involves similar characteristics to the CMJ and DJ, it could be argued that similar relationships between CMRJ metrics and linear sprint time would be expected, but, as of yet, these associations have not been determined. Research has also shown a variety of associations between jumping metrics and COD speed. [PERSON] et al. [18] reported that CMJ height showed a moderate inverse correlation with 505 test times (\(r=-0.46\), \(p<0.05\)), but only on the side that exhibited the faster 505 test times. In another study, by [PERSON] et al. [3], a similar correlation was observed between CMJ height and 10 m COD time (i.e., sprint 5 m to the line, turning 180\({}^{\circ}\), and sprint 5 m back to starting line; \(r=-0.43\), \(p<0.05\)). [PERSON] et al. [14] firstly investigated the association between the reactive strength index modified (RSImod, a ratio between JH in CMJ and time to take-off [TTTO]) and 505 test time, showing significant moderate to large correlations between these two metrics (\(r=-0.30\) to \(-0.57\), \(p\leq 0.05\)). A greater RSImod value requires athletes to jump as high as possible (applying large amounts of force vertically) whilst spending minimal time on the ground [2]. Similarly, a short 505 test time requires athletes to sprint maximally (applying large amounts of force horizontally) whilst entering and exiting the COD as fast as they can [14; 15]. Noting that whereas the direction of force application is different between these tests, the capability to rapidly produce braking and propulsive forces is equally vital to both RSImod and COD speed [14]. Given that the DJ and COD tests share similarities in lower extremity push-off mechanisms, a large correlation between metrics measured from the DJ and COD tests might be expected. In addition, [PERSON] et al. [6] reported large correlations between the RSI and COD speed (\(r=-0.65\), \(p=0.001\)). In contrast, [PERSON] et al. [17] found trivial relationships between the RSI and COD speed (505-left: \(r=0.13\), 505-right: \(r=-0.14\), \(p>0.05\)), while [PERSON] et al. [19] revealed that DJ height showed trivial correlations with COD speed (\(r=-0.29\), \(p>0.05\)). Collectively, though, researchers have not clarified why CMJ and DJ tests reported different associations with COD speed across various studies [3; 6; 17; 19]. In addition, it is clear that athletes need to generate large amounts of force to jump, sprint, or change direction--a quality which can be evaluated reliably from the isometric mid-thigh pull (IMTP) [20]. Typically, the peak force (PF) determined during the IMTP test has been proved to have meaningful associations with 20 m sprint time (\(r=-0.69\), \(p\leq 0.01\)) [21], COD time (\(r=-0.69\), \(p\leq 0.05\)) [21], and jump performance (including JH and RSI, \(r=0.36\) to 0.82, \(p<0.05\)) [22]. However, there is a paucity of research investigating the associations between metrics derived from the CMRJ (e.g., countermovement depth [CM depth], JH, leg stiffness [Kleg], TTTO, GCT, RSI, RSImod) and the aforementioned athletic performance measures (e.g., 20 m sprint time, COD time, and force measured from IMTP). Thus, further research is required to provide a sound biological basis for practitioners utilizing this assessment in their routine monitoring processes [2]. Therefore, the aim of this study was to determine if there are any meaningful associations between CMRJ performance and independent measures of athletic performance.