# Biomechanical Assessment of Throwing Gesture and Performance in Female Water-Polo Players
## 4 Discussion  
The present study proposed the comparative analysis of throwing kinematics in three different types of water-polo shots and the biomechanical investigation of the throwing performance in female water-polo players. Experimental tests were conducted before and after a specific training program. Similarly to other studies that focused on the effect of high-intensity training on performance in water-polo players [15; 26], it was not possible to establish a control group, due to the limited number of players. We will discuss results obtained in two different experimental sessions, _Pre_ and _Post_ the additional training program, but due to the lack of the control group it is not possible to infer the effectiveness of the specific training program. For each shot type (PS, PSS, PFS), the main findings highlight differences in shoulder kinematics, throwing velocity, and precision score for specific types of shot after training, while power does not show significant changes. Based on previous studies, it is widely accepted that the throwing velocity of the ball and the player's vertical jumping ability are essential skills for shooting in water-polo [18]. For this reason, the throwing velocity was considered the kinematic parameter of interest. The current study presented the maximum velocity calculated along the \(y\)-axis (Figure 5A). Values are comparable to results presented by [PERSON] et al. [17] and [PERSON] et al. [18] who analyzed the relationship between the throwing velocity and anthropometric characteristics in female water-polo players. [PERSON] et al. [17] found a  
Figure 6: Regression analysis between the shoulder and elbow angles (**A**). Regression analysis of the maximum velocity (along the \(y\)-axis direction) and shoulder (**B**) and elbow (**C**) angles. All the estimations were performed both before (_Pre_) and after (_Post_) the training program. median value of throwing velocity of 15.3 m/s when performing free-style penalty shot, while an average value of 15.5 m/s was found by [PERSON] et al. [18]. In the present study, all the three types of shots presented comparable values of throwing velocity. No differences were pointed out in the comparison between _Pre_ and _Post_ training for the PS and PSS shots, while the PFS shot showed a significant reduction in the maximum velocity after the training (14.7 m/s before the training, 13.9 m/s after the training, _p_-value = 0.005). The advantage of faster shots is related to the smaller time of interception by the opposing team, independently from the precision [17], but the request for a more precise shot might influence the throwing velocity with a reduction in maximum values. Considering the shoulder angular kinematics, all the three shots revealed results comparable with average values of 65\({}^{\circ}\) obtained in [24]. In particular, the most similar value was obtained in the PSS after the training program. In addition, in the PFS shot the shoulder rotation was increased (7\({}^{\circ}\) greater in the _Post_ training test, _p_-value = 0.003) after the training program, while no significant differences were obtained in the PS and PSS shots. Considering the elbow angle, [PERSON] et al. [24] found an average value of 46\({}^{\circ}\). In the present study, all the shot conditions revealed lower elbow angles, but the most similar was obtained in the PSS shot after the training session (37.4\({}^{\circ}\)). Moreover, a moderate correlation between shoulder rotation and elbow flexion was confirmed in all the three types of shots, both before (R = 0.47) and after the training (R = 0.51). This result demonstrates the influence of each joint on the rotation and on the final position of the upper limb during the movement. The increase in shoulder angle and the reduction in ball velocity after the training can be explained by the request for a higher precision in performing the shot. Current findings are in agreement with previous literature. [PERSON] et al. [24] stressed the relationship between upper arm kinematics and throwing performance.