Biodynamics and Human Performance Center, Armstrong State University, Savannah, Georgia.
J Strength Cond Res. 2019 Jul;33 Suppl 1:S70-S77. doi: 10.1519/JSC.0000000000002545.
Krajewski, K, LeFavi, R, and Riemann, B. A biomechanical analysis of the effects of bouncing the barbell in the conventional deadlift. J Strength Cond Res 33(7S): S70-S77, 2019-The purpose of this study is to analyze biomechanical differences between the bounce and pause styles of deadlifting. Twenty physically active males performed deadlifts at their 75% one-repetition maximum testing using both pause and bounce techniques in a within-subjects randomized study design. The average peak height the barbell attained from the 3 bounce style repetitions was used to compute a compatible phase for analysis of the pause style repetitions. Net joint moment impulse (NJMI), work, average vertical ground reaction force (vGRF), vGRF impulse, and phase time were computed for 2 phases, liftoff to peak barbell height and the entire ascent. Additionally, the ankle, knee, hip, and trunk angles at the location of peak barbell bounce height were computed. During the liftoff to peak barbell height phase, although each of the joints demonstrated significantly less NJMI and work during the bounce style, the hip joint was impacted the most. The average vGRF was greater for the bounce; however, the vGRF impulse was greater for the pause. The NJMI results for the ascent phase were similar to the liftoff to peak barbell height phase, whereas work was significantly less for the bounce condition compared with the pause condition across all 3 joints. Strength and conditioning specialists using the deadlift should be aware that the bounce technique does not allow the athlete to develop maximal force production in the early portion of the lift. Further analyses should focus on joint angles and potential vulnerability to injury when the barbell momentum generated from the bounce is lost.
克拉耶夫斯基、K、勒法维、R 和里曼、B. 杠铃在传统硬拉中反弹的生物力学分析。J 强能力研究 33（7S）：S70-S77，2019-本研究的目的是分析硬拉中反弹和暂停两种风格的生物力学差异。20 名身体素质活跃的男性在其 75%一次重复最大测试中使用暂停和反弹技术进行了硬拉，采用了一种在个体内随机研究设计。使用 3 次反弹风格重复中杠铃达到的平均峰值高度来计算用于分析暂停风格重复的兼容阶段。净关节力矩冲量 (NJMI)、功、平均垂直地面反作用力 (vGRF)、vGRF 冲量和阶段时间分别计算了 2 个阶段，从离地到达到峰值杠铃高度和整个上升阶段。此外，还计算了在达到峰值杠铃反弹高度的位置处的踝关节、膝关节、髋关节和躯干角度。在离地到达到峰值杠铃高度的阶段，尽管在反弹风格中每个关节的 NJMI 和功都明显减少，但髋关节受到的影响最大。平均 vGRF 反弹较大；然而，暂停的 vGRF 冲量更大。上升阶段的 NJMI 结果与离地到达到峰值杠铃高度阶段相似，而在所有 3 个关节中，反弹条件下的功明显小于暂停条件。使用硬拉的力量和体能专家应该意识到，反弹技术不允许运动员在举重的早期产生最大的力量。进一步的分析应该集中在关节角度和当从反弹产生的杠铃动量丢失时潜在的受伤脆弱性上。
