## 4 Discussion  
The current study examined the relationships between ball velocity and kinematic variables during the jump throwing of elite handball players. The main aim was to determine the relationships between ball velocity and right hand (throwing hand) linear kinematics, as well as right arm and left leg (take-off leg) angular kinematics during three investigated phases over eight events. The results in Table 1 show that the kinematic variables at maximum ground reaction force, maximum height of body center of gravity during flight, release ball and ground contact events were correlated strongly with ball velocity. These findings support a previous study which indicated important kinematic variables of the standing throw in handball [23]. The analysis of the cocking phase in our study indicated a moderate correlation between ball velocity and the velocity of the right hand at IC (Y, R) and IF (Y). This finding indicates that the primary velocity of elbow and the initial flight with the ball increased the ball velocity. During the same phase, the right-hand acceleration had a strong correlation with ball velocity at Max-GRF (Y). This strong correlation indicates that the Max-GRF during the jump throwing improved the horizontal velocity of the right hand (elbow and wrist joint) before ball release, which led to improving the arm swing during throwing. The displacement of the right hand during the acceleration phase was strongly correlated with ball velocity at Max-CGH (Y), RB (Y) and RB (R). In addition, the Max-HH (R) during this phase correlated moderately with the ball velocity. This finding implies that maximum height of body GC and the dominant throwing hand increase the kinematic requirements of the hip and shoulder to maintain a high velocity of ball and performance; [PERSON] and [PERSON] [24] showed some kinematic changes during overarm throwing related to the elbow extension and internal rotation. Furthermore, the velocity of the right hand correlated strongly with Max-HH (Y) and moderately with Max-HH (R). The positive correlation with ball velocity and maximum heights of the throwing hand (Y, R) coordinates during the acceleration phase implies that arm motion continues until ball release time, which generates a ball rotation around the central axis, increases and generates the required release ball velocity. This supports the study of [PERSON], et al. [25], who suggested that the arm acceleration phase is the dynamic phase between the maximum external shoulder rotation and the instant of ball release. During the follow-through phase, the results indicated that a higher correlation between ball velocity and the displacement of the right hand at GC (Y and R), and the velocity of the right hand had a high correlation at GC (Y). However, a moderate correlation was seen during this phase with the acceleration of the right hand at GC (Y). A strong correlation of displacement and velocity were found during this phase, so we suggest that when players perform the jump throw, they must increase their movement horizontally to enable forward movement at the landing. [PERSON], et al. [26] indicated that the ability of skilled throwers to optimize the throwing arm event of inertia during the arm cocking and arm acceleration phases highlights the importance of the arm movement to reach a high ball velocity. Our findings in Table 2 indicate that the moderate negative correlation between ball velocity and the right elbow angle during the Max-HH event. This finding indicates that the smaller angle at the elbow joint assists in the improvement of a higher ball velocity at release for longer throwing. This finding supports previous studies [8; 15; 23], which indicated that the elbow extension and internal rotation velocity were factors for fast shoulder throwing, wherein about 73% of the contribution of ball velocity was based on the maximal internal rotation velocity of the shoulder and maximal elbow extension during the throw.