## 3 Data Treatment and Analysis
### Results
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Articles** & **Participants** & **Capture System** & **Serve Types** & **Aim of the Study** & **Main Findings** \\ \hline \multirow{9}{*}{[PERSON] 2015 [26]} & \multirow{9}{*}{10 professional men, 25.3 \(\pm\) 3.6 y, 184.9 \(\pm\) 6.28 km, 81.6 \(\pm\) 9.81 kg} & \multirow{9}{*}{1400 Hz Basler PiA640} & This study aimed to examine whether serving players use the same ball toss for kick serve (KS) and slice serve (SS) in two different directions of serves, from the receiver’s view. & They found differences in the ball toss execution between KS and SS. The vertical toss peak of KS was the same ball toss for kick serve (KS) and slice serve (SS) in two different directions of serves, from the receiver’s view. & The study was made to analyze the variability and stability of the serve toss in tennis on the x (side-to-side), y (back-to-front), and z (vertical) axes, under the influence of crosswind (induced aerodynamic flow) produced by an industrial ventilator. & The vertical dimension of the tennis serve is assumed as a constant feature, which is guaranteed in the remaining varying dimensions (y and \(x\)-axis) of the ball toss. Thus, the variability should be seen as part of the solution and not as something to be avoided by players and coaches. \\ \cline{2-6}  & \multirow{2}{*}{5 junior men [27]} & \multirow{2}{*}{22 cameras} & The study investigated the immediate effects of the decomposition on kinematics, offering insight into their efficacy in developing the serve. & Vertical displacement of the ball at its zenith increased significantly during BT compared with the FS and temporal associations between racket and ball motion during the FS (r = 0.861) were affected during task decomposition. \\ \hline \multirow{9}{*}{[PERSON] 2021 [20]} & \multirow{9}{*}{14 junior women, 13.6 \(\pm\) 1.7 y, 169.8 \(\pm\) 12.7 cm, 169.8 \(\pm\) 13.1 kg} & \multirow{9}{*}{12 cameras, 250 Hz VICON MX} & This study aimed to compare the flat and kick serve & Pelvis and ball toss kinematics vary with gender and serve type but not necessarily abnormality in the elite adolescent serve. There is evidence to suggest that the order and timing of key serve events & Pelvis and ball toss kinematics vary with gender and serve type but not necessarily abnormality in the elite adolescent serve. There is evidence to suggest that the order and timing of key serve events might help to identify those at risk of lumbar spine abnormalities & The results underline biomechanical differences regarding the starting position (feet and upper torso) and the movement and ball kinematics that could be relevant for skill acquisition, injury prevention, and performance enhancement. \\ \cline{2-6}  & \multirow{2}{*}{8 professional men, 25.3 \(\pm\) 3.6 y, 184.9 \(\pm\) 6.28 km, 81.6 \(\pm\) 9.81 kg} & \multirow{2}{*}{10 cameras 500 Hz VICON MX} & This study aimed to contrast the effect of the removal of visual feedback on the ball and racket kinematics spatiotemporal regulation of the serve. & These results highlight that the removal of visual feedback on the ball and racket kinematics spatiotemporal regulation of the serve. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._The graphical presentations of the pooled data from the individual studies are presented in two forest plots, one for FS and one for KS, each with three subgraphs for the \(x\), \(y\), and \(z\) axes (Figure 3). Comparing the normalized weighted mean (Supplementary Materials, Table S2) of the BI location among the individual groups within FS; on the \(x\)-axis: the most