# Goal Shot Analysis in Elite Water Polo--World Cup Final 2018 in Berlin
## 4 Discussion
### Biomechanical Analysis of the Goal Shot Behavior of Individual Players  
Throwing speed is probably one of the most important performance prerequisite in water polo at all performance levels--together with swimming speed--[1; 2; 15] and therefore rightly forms a central focus of the present study. In the case of the drive shot, which is dominantly used in water polo with more than 85%, it is possible to distinguish between the variants of (a) direct goal throw, (b) goal shot after feining and (c) goal throw directly from catching [19]. Doing so, but a systematic difference between the ball velocities cannot be detected [21]. According to [22], on the side of the more general performance characteristics of the players' the age [17] and body height [21] are primary variables that influence the throwing velocity. On the side of the trainable physical components, hand grip strength [36] as well as shoulder rotator strength [18; 37], specifically the pectoralis major muscle and deltoid muscle strength [38], and in-water shoulder proprioception [39], are the main determinants of throwing speed. Also a positive impact on throw velocity was shown for the vertical jump height by means of the water polo boost, and the height of the head above the water surface during the throw [17]. Both features are based mainly on the quickness and technical quality of the leg movement [18; 22]. Notwithstanding these influential determinants, however, it seems that individual throwing behavior represents an independent dimension (in terms of factor analysis) of water polo performance [21].  
In the context of the present study, it is particularly noteworthy that in the throwing behavior of the current men's world class since the 1980s, the throwing velocity continues to increase unabated (especially considering the maximum values in the range of 26-27 ms\({}^{-1}\)), ranged from 19.1 ms\({}^{-1}\) (penalty shot from a distance of 4 m at that time; [6]) to 20.2 ms\({}^{-1}\) (\(\pm\)1.4 ms\({}^{-1}\)) at the 1997 FINA World Cup in Athens [16], to the most recent value reported by [22] measured throwing velocity of 22.8 ms\({}^{-1}\) (\(\pm\)2.8 ms\({}^{-1}\)) in Italian first division players, up to the average velocity of 21.62 ms\({}^{-1}\) (\(\pm\)1.90 ms\({}^{-1}\)) currently diagnosed in the present study.  
This increase of the throwing speed in the course of the last 15 years by about 9% may be regarded as an obvious concomitant of the professionalization of the water polo sport especially in the nations of the Mediterranean area. This considerable increase in speed is also underlined by the fact that the throwing speeds measured by [6] in the 1980s are now already achieved by 15-18-year-old Croatian junior national players with 19.91 ms\({}^{-1}\) (\(\pm\)0.91 ms\({}^{-1}\); [40]). In general, it should also be noted that goal throws under competitive match conditions--at least according to the comparison made by [1; 2] in top Spanish female players--have a ball velocity up to 3 ms\({}^{-1}\) (\(p<0.05\)) higher than drive shots throws performed on the empty goal under laboratory conditions.  
With respect to goal throw in competitive play, it is further noteworthy that it has not yet been conclusively determined whether throwing velocity in water polo depends on immediate player stress. Whereas [20] found significantly higher throwing velocities, at least for intermediate-level women, at 11.63 ms\({}^{-1}\) (\(\pm\)1.40 ms\({}^{-1}\)) in an unstressed control situation compared to 11.21 ms\({}^{-1}\) (\(\pm\)1.23 ms\({}^{-1}\); \(p<0.05\)) within a series of repeated sprint loads, neither [41] in juniors, nor [35] in first-line Greek players have found fatigue-induced decreases in throwing velocity in the male high performance range. One reason for this contradiction is likely to be the general, lower physical performance level of women's water polo, where even top female players have throwing speeds approximately 4-5 ms\({}^{-1}\) lower than men [6].