增加離心收縮階段的重量負荷對向心收縮階段爆發力表現的影響

Abstract

目的：在進行垂直跳及仰臥推擲時，增加不同的離心收縮負荷，是否能提升隨後向心收縮時的力量、速度與功率峰值的表現；並進一步檢驗最適當的離心收縮負荷是否與參與者的最大肌力/體重之倍數呈相關。方法：以 12名有阻力訓練經驗之健康男性，採用重複量數與平衡次序的實驗設計，讓參與者分別進行不同離心收縮負荷處理之垂直跳與仰臥推擲測驗，藉由掛勾裝置操弄下肢的離心/向心收縮負荷分別為50%/50%、60%/50%、70%/50%、80%/50%向心1RM；上肢的離心/向心收縮負荷為30%/30%、40%/30%、50%/30%、60%/30%向心1RM。參與者分別進行2組2次反覆之垂直跳與仰臥推擲測驗，並以測力板與位移計分析垂直跳與仰臥推擲之力量、速度和功率峰值，藉以評估在離心收縮階段增加重量負荷對向心階段爆發力表現之影響。統計以重複量數單因子變異數分析，考驗在4種不同離心收縮負荷下，垂直跳與仰臥推擲之力量、速度和功率峰值是否有差異；並以皮爾遜積差相關分析，探討最適當離心收縮負荷與參與者最大肌力/體重之倍數的相關性，顯著水準定為p ≤.05。結果：進行垂直跳時，發現當離心/向心收縮負荷為70%/50%向心1RM時，功率峰值 (4070 ± 519瓦特) 顯著大於傳統的離心收縮負荷50%/50%向心1RM (3853 ± 640瓦特; p<.05)；進行仰臥推擲時，在4種不同離心收縮負荷下，其力量、速度與功率峰值皆未達顯著差異。此外，最適當的離心收縮負荷無論是與參與者的下肢或上肢最大肌力/體重之倍數皆未達顯著相關。結論：在進行垂直跳時，增加離心收縮時的負荷 (離心/向心收縮負荷為70%/50%向心1RM) 可以進一步提升隨後向心收縮時的功率峰值表現；然而，在進行仰臥推擲時，增加離心收縮時的負荷並不會提升隨後向心收縮時的爆發力表現。儘管，可以透過增加離心收縮負荷來進一步提升垂直跳的爆發力表現，但最適當離心收縮負荷的選擇並不會受到參與者肌力表現的影響。

Purpose: To examine whether increasing the eccentric loading in eccentric-concentric countermovement jump and bench throw can further enhance peak force, peak velocity, and peak power of the jump and throw. Furthermore, the purpose was to examine whether the optimal eccentric loading was correlated with the participant’s maximal strength / body weight ratio. Methods: A total of 12 resistance-trained men participated in the experiment using repeated measures design and counter-balance order. All participants performed 4 different treatments at eccentric/concentric loading of 50%/50%, 60%/50%, 70%/50%, 80%/50% concentric 1RM for countermovement jumps and at eccentric/concentric loading of 30%/30%, 40%/30%, 50%/30%, 60%/30% concentric 1RM for bench throws using weight releaser. All participants performed 2 sets of 2 jumps and 2 throws during each treatment. Force and displacement of jumps and throws were obtained by using force plate and transducer and peak force, peak velocity, and peak power were calculated to assess the acute effects of increased eccentric loading on power performance of jumps and throws. One-way repeated measures ANOVA and Pearson correlation coefficient were used to analyze the data. The significant level was set at p ≤.05. Results: When performing countermovement jump, significantly greater peak power (4070 ± 519 W) was observed in 70%/50% treatment when compared with 50%/50% treatment (3853 ± 640 W; p<.05); However, no significant differences were observed among 4 treatments in peak force, peak velocity, and peak power. In addition, the optimal eccentric loading was not correlated with the participant’s maximal strength/body weight ratio for both countermovement jumps and bench throws. Conclusion: When performing countermovement jump, the accentuated eccentric loading (eccentric/concentric loads of 70%/50% concentric 1RM) can further enhance the concentric peak power. However, the accentuated eccentric loading has no benefit on power performance of bench throws. Even though the accentuated eccentric loading can further enhance the power performance, the selection of the optimal eccentric loading is not affected by participant’s maximal strength.