隨著排球規則不斷修訂，排球比賽中的發球仍是目前影響比賽勝負的重要關鍵因素，現今的發球已朝向強力發球之趨勢發展，當發球威力不斷提升後，亦可能會造成發球失誤率的增加，發球雖然是排球技術中唯一不受他人影響的一項個人技術，但在比賽中需面臨許多心理因素的影響。然而當球隊因受發球表現影響而造成球隊接發球不理想或連續失分時，教練通常會請求暫停或是替補來予以應對，經本文探究文獻與資料後，可得知目前男子排球比賽中，發球表現受暫停所影響的程度較小，且多數是處於對方得分的情形下而提出暫停的請求，而不論是己方或對方在替補後發球的失誤表現仍然是偏高的。本文除探討影響發球表現的因素及暫停與替補對排球比賽影響層面外，並針對實際比賽中暫停與替補後的發球表現情形進行討論與建議，期能為國內排球研究或教練人員提供未來研究或訓練之參考。

In spite of the rapid development of volleyball rules, serving still has an importantly crucial influence on winning a game. Nowadays, since serving has had a trend to be more and more forceful and threatening, the probability of fault serving undoubtedly increases. Among all of the personal skills found in volleyball, serving is the only one that it is not easily affected by other players, but by personal emotional factors. When unsuccessful serving and improper receiving make a team suffer from losing points continuously, the coach usually has to ask for a substitution or timeout to retrieve the loss. After the previous discussion, it can be found that in men's volleyball games, when the opponent's side continuously gets points by serving, timeout has a less influential effect on serving with success. As for the substitution, it causes higher probability of fault serving than that caused by timeout. In order to help improvement the research of volleyball and offer coaches with practical information, this study investigated how substitution and timeout influenced the player's performance of serving in men's volleyball games.