a Biomechanics Research Unit , University of Limerick , Limerick , Ireland.
J Sports Sci. 2019 Jul;37(14):1591-1599. doi: 10.1080/02640414.2019.1577120. Epub 2019 Feb 6.
This study examined the kinetic and temporal differences between countermovement jumps (CMJs) and eccentrically loaded CMJs. A survey of 109 coaches and athlete showed that 87% of respondents regularly used jumps with added mass within training. Sixteen male and thirteen female track and field athletes from sprinting, hurdling and jumping events performed 5 bodyweight CMJs 5 jumps wearing a weighted jacket and 5 eccentrically loaded dumbbell (LDB) jumps trials in a randomised order. Peak force (PF), peak power (PP), flight time (FT), concentric time (CON-T), eccentric time (ECT), total time (TIME) and eccentric/concentric ratio (E/C-Ratio) were obtained from force plate data. Statistically significant differences (p < 0.05) with moderate to large magnitude effect sizes were found between men and women in FT, PP and PF but not in any of the temporal variables. The results indicated that the WJ decreased FT in men (↓9%) and women (↓10%) but LDB jumps had similar FT to CMJ. Overall, the results showed that LDB increased the E/C Ratio (↑50% and ↑42%) and decreased CON-T (↓37% and ↓25%) compared with WJ and CMJ respectively. LDB jumping is not recommended as a training modality as it tends to disrupt the relative timing of the jump action.
本研究考察了反向跳跃（CMJ）和偏心加载的 CMJ 之间的动力学和时间差异。对 109 名教练和运动员的调查显示，87%的受访者在训练中经常使用附加质量的跳跃。16 名男性和 13 名女性短跑、跨栏和跳跃项目的田径运动员在随机顺序下进行了 5 次体重 CMJ、5 次穿着加重夹克的跳跃和 5 次偏心加载哑铃（LDB）跳跃试验。从测力板数据中获得了峰值力（PF）、峰值功率（PP）、腾空时间（FT）、向心时间（CON-T）、离心时间（ECT）、总时间（TIME）和离心/向心比（E/C-Ratio）。FT、PP 和 PF 方面，男女之间存在统计学显著差异（p<0.05），具有中到大的效应量，但在任何时间变量中均无差异。结果表明，WJ 降低了男性（↓9%）和女性（↓10%）的 FT，但 LDB 跳跃的 FT 与 CMJ 相似。总体而言，与 WJ 和 CMJ 相比，LDB 跳跃增加了 E/C 比（↑50%和↑42%），减少了 CON-T（↓37%和↓25%）。不建议将 LDB 跳跃作为一种训练方式，因为它往往会打乱跳跃动作的相对时间。
