背景與目的：探討男童增強式訓練後停止訓練，不同後測時間點之30公尺短跑衝刺成績及變化率差異。方法：16位男童選手（12.28 ± 0.46歲）為研究對象，依前測（T1）成績隨機分派成實驗組與控制組。前者接受8週增強式訓練（PT組），同時維持排球年度訓練課程；後者（C組）僅進行排球年度訓練課程。PT組增強式訓練結束後，依時間序：訓練8週之後測（T2）、停訓2週（T3）、停訓3週（T4），收集30公尺短跑衝刺後測時間，並換算各階段差異變化率（%）。進行混合二因子（組別 × 後測時間）變異數分析，統計顯著水準定為α=.05。結果：（1）不同測驗時間之30公尺短跑衝刺時間，達顯著差異；（2）8週訓練後，僅T1－T2變化率組間達顯著差異；（3）PT組T2－T3變化率，顯著較T1－T2少4.9%。結論：（1）8週增強式訓練後，PT組較C組提升30公尺短跑衝刺進步率4.7%。（2）2週停止訓練後，訓練效果明顯下降。（3）3週停止訓練後，訓練效果回升至8週訓練剛結束時之水準。

Background. In children, limited information regarding plyometric exercise is available. The purpose of this study was to examine the effectiveness of plyometric training and maintenance training on 30 meters sprint performances in prepubescent volleyball players. Methods. 16 boys aged 12 years (12.28 ± 0.46 yrs) was divided in 2 groups: plyometric training group (PTG) and control group (CG). PTG trained 2 days/week during 8 weeks, and performed various plyometric exercises including jumping, hurdling and skipping. The subsequent reduced training period lasted 2 weeks and 3 weeks. However, all subjects continued their volleyball training.30-meter-sprintrunning time improving percentage (%) was calculated: T1 - T2 (pretest-posttest), T2 - T3 (detrain 2 weeks), and T3-T4 (detrain 3 weeks). Results. Before training, all baseline anthropometric characteristics were similar between PTG and CG. After the training program, 30-meter-sprint performances increased in the PTG. There was no interaction between × groups duration. During this period no significant performance was obtained in the CG. After the 2-week of detraining, both groups sprint improving percentage were minus ＂-＂, there was a significant performance decline for PTG and CG; After the 3-week of detraining (T3-T4) ,there were no significant decline compared with posttest (T1-T2) in sprint improving percentage for PTG and CG. Conclusions. These results demonstrate that 8-weeks plyometric training program increase athletic sprint performances in prepubescent boys. These improvements were maintained after a period of 3 weeks detraining.