## 2 Materials and Methods
### Procedures  
To identify the intra- and interday reliability of the CMJ and DJ metrics, a randomized cross-over within the subject design was used (Figure 1). \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Mean** & **SD** \\ \hline Age (Years) & 20.3 & 2.5 \\ Weight (kg) & 61.3 & 8.4 \\ Height (m) & 1.6 & 0.04 \\ Body Mass Index (kg/m\({}^{2}\)) & 21.9 & 2.6 \\ Fat percentage (\%) & 24.7 & 4.9 \\ Fat mass (kg) & 15.6 & 4.3 \\ Fat free mass (kg) & 15.5 & 4.1 \\ Basal metabolic rate (Kcal) & 1454 & 108.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptive characteristics of the participants. Figure 1: Flow chart of the experiment. Participants performed 3 CMJs and 3 DJs trials on a force platform, in a randomized order, separated by one week. Each attempt was separated by at least 3 min of passive recovery. Each jump for both tests were performed on a Force-Decks FD4000 Dual Force platform (ForceDecks London, United Kingdom) with a sampling rate of 1000 Hz. The vertical ground reaction force data obtained from each jump were inputted into the ForceDecks software (ForceDecks, London, United Kingdom) for analysis. A fourth-order Butterworth low-pass filter with a cut-off frequency of 50 Hz was used to generate all the dependent variables for each jump. All dependent variables were calculated using forward dynamics [19]. One week prior to the first testing session, participants performed a familiarization session to ensure an appropriate CMJ and DJ technique. For participants' description, body composition was analyzed through bioelectrical impedance [26]. All assessments were conducted in a room adjacent to a multi-sport indoor court within the same sports facility. During the in-season training period, all testing was conducted within a 3-week time frame. Each subject participated in three different sessions of jump assessments, consisting of one familiarization session and two evaluation sessions. Participants' performed 3 countermovement jump (CMJ) and 3 drop jump (DJ) exercises in each session. The order of the jump type was randomized, and during the second evaluation session, subjects performed the jumps in the same order. A rest period of at least 3 min was given between each jump trial. To ensure consistency, both testing sessions were conducted within the same hour in the afternoon, between 19:00 and 20:00, as the previous literature has indicated the influence of time of day on jump performance [27; 28]. To standardize the two assessments without compromising the ecological validity of the results, the tests were conducted on the same training day within their typical weekly microcycle structure (Three training sessions per week and one competition on Sunday). The assessments were performed on match day (MD)-3 (Thursday). Additionally, the training loads of the two preceding workouts of that week (MD + 1 and MD-4) were analyzed to ensure the same training load. A previously described TL quantification method was employed: sRPE = volume in minutes x RPE [29; 30]. In both evaluation weeks, the training load was similar in both MD + 1 and MD-4 (\(p>0.05\)). Additionally, subjects were instructed not to engage in any physical exertion before arriving for testing. For ecological validity, subjects wore their standard practice gear, including their chosen shoes, and they were required to wear the same pair of shoes during both testing sessions. All testing was conducted at the participants' volleyball training facility. No dietary restrictions were implemented; however, athletes were advised to maintain their normal dietary intake. For testing days, participants were asked to refrain from alcohol and caffeine for 24 h prior to the session to minimize their impact on jump performance [31; 32]. To minimize the effect of instructions on jumping performance, the instructions provided to participants were standardized. A 3-2-1 countdown followed by a verbal stimulus was performed to support maximal effort during jump execution.