## 1 Introduction  
Jump actions appear frequently in many sports; thus, they represent a time-efficient means of assessing lower body explosive power capabilities [1; 2; 3]. Whilst a plethora of options are available, the countermovement jump (CMJ) and drop jump (DJ) represent useful and commonly applied methods of assessing slow and fast stretch-shortening cycle (SSC) mechanics, respectively [4; 5]. However, testing large squads of athletes with both jumps naturally extends the duration of any given test session, which may not always be favorable when time is finite in elite sport settings [1]. In this instance, the countermovement rebound jump (CMRJ) that combines the characteristics of both the CMJ and DJ might be a viable alternative and allow practitioners access to comparable information [6]. The CMRJ requires athletes to perform an initial maximal effort CMJ (i.e., CMRJ1), immediately followed by a second, reactive vertical drop jump (i.e., CMRJ2) which requires athletes to again focus on maximal jump height, whilst also minimizing ground contact time (GCT) [7]. Typically, jump performance has been discussed pertaining to the jump height measurement during CMJ, DJ, and CMRJ [5; 7; 8]. However, athletes may use a variety of take-off strategies (i.e., hip or knee dominant), resulting in different levels of joint work during the propulsive phase, whilst still achieving the same jump height [9]. Meanwhile, simply measuring jump height alone is a poor reflection of the utilization of SSC mechanics to store and use elastic strain energy [10]. Therefore, joint kinetic analysis focusing on the total positive or negative joint work (and total joint contribution) offers a more detailed insight into how an athlete utilizes their lower extremity joints (i.e., hip, knee, and ankle) to achieve a given outcome [10; 11]. For example, [PERSON] and [PERSON] [11] conducted research to see the primary joint contributor to the total joint work done during a CMJ. They revealed that the knee joint (mean work: 330 \(\pm\) 111 joule [J]) contributed to around 49% of the total positive work, with the remaining 51% of the work done by the ankle (161 \(\pm\) 51 J; 23%) and hip joints (188 \(\pm\) 76 J; 28%). In support of this, [PERSON] et al. [12] argued that the work done by the ankle (2.06 J/kg) and knee joints (1.94 J/kg) were similar during a CMJ, and these values also remained unchanged when jump height increased. However, they also revealed that the hip joint work showed a significant increase from 1.03 J/kg to 3.24 J/kg as jump height increased (\(p\leq\) 0.001, omega squared \(w^{2}\) = 0.79), highlighting the biggest contributor to total positive work was actually the hip joint. More recently, [PERSON] et al. [10] proposed that all three lower extremity joints contributed to different positive and negative work (i.e., a net extensor moment combined with joint extension is presented as positive, a net flexor moment combined with joint flexion is negative) during the CMJ. In accordance with [PERSON] and [PERSON] [11], [PERSON] et al. [10] found the knee joint contributed to the majority of total negative and positive works (negative: 54.52 \(\pm\) 14.09%; positive: 41.43 \(\pm\) 8.26%) compared to the hip (negative: 39.78 \(\pm\) 15.17%; positive: 32.14 \(\pm\) 8.68%) and ankle joints (negative: 5.71 \(\pm\) 3.69%; positive: 26.44 \(\pm\) 4.85%). A couple of variables including the involvement of arm swing, the countermovement depth (CM depth), a variety of take-off strategies, or the sex of participants might explain the differences seen from the aforementioned studies [9; 10; 12]. When considering the DJ, two previous studies have found that the hip joint only contributed 13% and 19% of total positive work done [13; 14]. These values were notably less than the CMJ (23% to 39%) [11; 14], pointing to the notion that the ankle and knee joints contributed a greater portion to the total positive work done in the DJ.