## 4 Discussion  
This study aimed to (1) determine the between-session reliability of all metrics measured during the CMJ, DJ, and CMRJ tests and (2) determine the differences in measured variables between the three jump types during two testing sessions. The main findings of this study showed that all variables consistently demonstrated moderate to excellent reliability across all three jump types, while the negative and positive hip joint works and contributions in all three jump types and negative ankle work and contributions in CMJ and CMRJ1 showed good to poor CV. Of all strategy-based metrics, only TTTO revealed significant small differences between CMRJ against CMJ and DJ tests. Furthermore, some of the kinetic variables (negative and positive hip and knee works and positive ankle contribution) significantly differed between the jump tests with trivial to moderate ES. In line with the previous research [7], the present study found that jump height and all strategy-based metrics exhibited good to excellent between-session reliability in each jump (ICC \(\geq\) 0.89), with good to moderate CV (\(\leq\)8.64%). Thus, our first hypothesis regarding the reliability of measured metrics was confirmed. In CMJ and CMRJ1, we observed questionable reliability in negative and positive hip joint work (CV \(\leq\) 20.95%) and contributions (CV \(\leq\) 19.29%), and negative ankle work (CV \(\leq\) 15.58%) and contributions (CV \(\leq\) 15.51%). This suggests an altered joint dominant strategy was used to achieve certain braking or propulsive impulse based on environmental factors, movement constraints, or other individual confounding factors [34]. Although speculative, the most influential factor may have been the unrestricted CM depth which enabled participants to manipulate their COM positions to a variety of heights between test sessions (as reflected by the moderate CV values of this metric). Naturally, the previous research has shown that variations in CM depth causes changes in joint angles during the braking and propulsive phases of the CMJ [35; 36]. Considering that joint work in the present investigation was obtained by integrating the joint power, which is the product of joint force and angular velocity [10; 12], it becomes evident that the variability in joint angles can have a substantial impact on the calculated joint work and contribution. In addition, the only variables in DJ and CMRJ2 showing questionable reliability were negative and positive hip work (CV \(\leq\) 25.04%) and contributions (CV \(\leq\) 24.11%). As aforementioned, no internal verbal cues were given to  
Figure 4: A summary of the total negative and positive work in each individual joint during drop jump and countermovement rebound jump 2 in both test sessions. The positive values indicate the positive work. The negative values indicate the negative work. direct participants' attention to segment movement patterns [22]. Since quickness and higher displacement were the only requirements to complete DJ and CMRJ2, participants relied primarily on their knee and ankle joints during the braking and propulsive phases. With this in mind, only a small portion of the total negative and positive work was done by the hip joint [16], which might in part explain the greater bandwidth of variations associated with the hip joint. Overall, variables such as the individual joint work and contribution to the total work appear to be more variable when monitoring jump performance. Practitioners, therefore, should be mindful of this when aiming to establish meaningful changes between testing sessions. Systematic bias was assessed between test sessions for all metrics, with no significant differences reported. Considering the joint work and contributions during CMJ and CMRJ1 tests, the knee joint was the biggest contributor to the total negative and positive work, which was consistent with the previous studies [10; 11; 14; 37]. In terms of the second and third contributors, [PERSON] et al.