Eye Tracking Strategies during Setting among Volleyball Players of Different Skill Levels

Abstract

The purposes of this study was to investigate the differences of decision-making time and area of interest (AOI) setting phase during setting among college female volleyball players of different skill levels. Fifteen elite, sixteen sub-elite volleyball players, and fourteen novices were recruited for this study. Five types of setting films were recorded by using high speed camera, and each film was separated into three setting phases: before setting, during setting and after setting. In addition, the frames of the film were separated into three AOIs, including the arm, the body and the ball. During watching the videos, the subjects needed to press the ＂space＂ immediately to determine decision-making time, and the positions of pupils of the eyes were simultaneously recorded by the iView RED eye tracker. The results showed that both elite and sub-elite players spent significantly lesser decision-making time and higher accuracy than the novices. Before setting, the elite players spent significantly more time than the novices to fix at AOI. During setting the elite and sub-elite players spent significantly more time than the novices to fix at AOI, while there were no significant differences among three groups after setting. The percentage of AOI on the ball of the sub-elite players and novices were significant higher than the elite players. Furthermore we found significant differences among three groups of the percentage of AOI on the arm; the sub-elite players were predominant compared to the elite players of the percentage of the AOI on the body. These findings concluded that the elite players could make a faster decision by staring at the arm movement of the setter, which might be result from the knowledge and recognition ability related to volleyball. Thus, the skilled players can efficiently process the relevant information.

本研究目的為探討不同技術水準之大專女子排球員，在判斷舉球員舉球時的決策時間、舉球時段與興趣區域（area of interest, AOI）的差異。以15位優秀選手、16位一般選手與14位無經驗者為研究對象。研究中以高速攝影機拍攝舉球員五種不同舉球球路，將舉球時段分為手觸球前、舉球過程與球離手後，並將AOI分為手臂、身體與球體。以iView RED眼動儀，收取受試者觀看影片時眼球瞳孔位置，於過程中受試者若已能確定舉球員舉出的球路，立即按下鍵盤上「空白鍵」，獲得決策時間。研究結果如下：一、優秀選手組與一般選手組在決策時間上皆顯著較無經驗組快，且正確率較高。二、在手觸球前的AOI，優秀選手組凝視AOI的時間顯著多於無經驗組；在舉球過程的AOI，優秀選手組與一般選手組在舉球過程的凝視AOI的時間顯著多於無經驗組；在球離手後的AOI，三組別間無顯著的差異。三、無經驗組及一般選手組對球體的AOI顯著的重視於較優秀選手組；優秀選手組、一般選手組與無經驗組在手臂的AOI間的重視程度均達顯著；一般選手組在身體AOI顯著的重視於優秀選手組。本研究結論：優秀選手能夠透過對方舉球員的手臂動作較快做出決策，這可能是因為對於運動的知識、辨識能力等因素上的不同所造成，使其能有效的處理相關的訊息。