目的：透過桌球正手擊球的實驗工作，探討變異練習與恆常練習對青少年動作表現與動作學習的效應。方法：實驗參加者為32名男性青少年，年齡14.4 ± 0.4歲，隨機分派到變異或恆常練習組。實驗流程為同質性考驗、150次的獲得期試作、以及5天後的保留和遷移測驗。依變項為桌球正手擊球測驗的得分值與變異誤差值。保留和遷移測驗所得實驗數據以獨立樣本t檢定考驗，而獲得期以2(組別) × 10(區間)混合設計二因子變異數分析與事後比較。結果：在獲得期中發現組別與區間的交互作用未達統計顯著差異(F (9, 270) = 0.23, p > .05)，但2組正手擊球得分值的主要效果則達統計上的顯著差異 (F (1, 270) = 1.84, p < .05, ES = 0.38)，2組變異誤差值的交互作用亦未達統計顯著差異(F (9, 270) = 1.82, p > .05)；保留測驗方面，變異與恆常練習兩組的得分值(t (30) = 1.602, p > .05)以及變異誤差值(t (30) = 1.431, p > .05)均未達統計顯著差異；遷移測驗的得分值(t (30) = 0.929, p > .05)和變異誤差值(t (30) = -1.303, p > .05)也未達統計顯著差異。結論：恆常的練習安排較變異練習有助於青少年在桌球正手擊球動作表現上的提升，但在動作學習上恆常與變異2種練習方式卻沒有不同的效應。

Purpose: To examine the effects of variable and constant practice on motor performance and learning in teenagers by the forehand stroke of table tennis. Methods: Thirty-two male participants (age = 14.4 ± 0.4 years) were randomly assigned to variable or constant practice group. The process consisted of four phases: homogeneousness test, 150 trials for acquisition, and retention and transfer tests after 5 days of acquisition phase. Dependent variables were scores and variable error (VE). Results: ANOVA for 2 (group) × 10 (block) indicated that no interactions were found (F (9, 270) = 0.23, p > .05), but the main effect of the scores in both groups was statistically significant difference in acquisition phase (F (1, 270) = 1.84, p < .05, ES = 0.38). The interaction of VE between groups and blocks was not found significant also (F (9, 270) = 1.82, p > .05); the scores (t (30) = 1.602, p > .05) and VE (t (30) = 1.431, p > .05) of the two groups were no significant in retention test; furthermore, the scores (t (30) = 0.929, p > .05) and VE scores (t (30) = -1.303, p > .05) in transfer test were not significant. Conclusions: It was concluded that the constant practice group was better than variable practice group on motor performance of the teenagers, but there were no differences between the groups on motor learning.