The effects of game specific task constraints on the outcome of the water polo shot
Wende, Katrina van der
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Recent research has highlighted that information-movement couplings are unique to the constraints of the task, environment and performer. This recent research implies that skills should be developed in practice environments that are reflective of those found in competition. Representative environments should also allow the performer to attune to specifying information essential for success of a skill. However, in water polo, shooting practice is often conducted without the presence of a goalkeeper or defender. The aim of this study was to determine the effect of game-specific task constraints on the ball speed, accuracy and technique of the water polo shot. Ten male competitive level water polo players performed a total of forty shots comprising ten shots in each of four conditions from the 4m-penalty line. Conditions included all combinations of goalkeeper and defender (absent or present). Three Sony mini-digital cameras (50Hz) were placed perpendicular to the movement, giving rear, overhead and a right sagittal view. Ball speed was measured using a Radar-gun (Stalker Pro, USA). For each condition, means and standard deviations were determined for all outcome measures (shooting accuracy and ball speed) and technique variables. A repeated measures ANOVA was used to determine the effect (p<0.05) of the goalkeeper and defender individually as well as in combination on the dependent variables. Cohen's effect sizes were also used to determine the magnitude of the difference between conditions. The presence of a defender resulted in a significant increase in lateral trunk flexion at ball release, decreased the duration of the shot and selected swing sub-phases (i.e. pick-up to top of back swing time) and significantly altered the placement of the ball in the goal. When the goalkeeper only was present, this resulted in decreases in total shot time and pick-up to top of back swing time and significantly altered the placement of the ball in the goal. The presence of the defender and goalkeeper in combination brought about a moderate effect, decreasing the ball speed, significantly decreasing the success of the shots, scores achieved and significantly altering the placement of shots. Forward swing distance and selected swing sub-phases (i.e. total shot time, pick-up to top of back swing time, forward swing start to midway and forward swing start to release) were also significantly decreased in the presence of the defender and goalkeeper. These findings highlight the importance of maintaining appropriate task constraints during water polo shooting practice. In effect the removal of the defender and goalkeeper leads to the development of inappropriate information-movement couplings. Specifically, the presence of the defender and/or goalkeeper lead to reductions in the durations of selected swing sub phases, resulting in changes in the relative coordination and timing of the water polo shot. These findings indicate that in order to facilitate the development of this specific shooting skill, coaches should structure practice to replicate the perceptual information available during competition.