Hay Dean, de Souza Vinicius Aguiar, Fukashiro Senshi
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komba 3-8-1, Meguro-ku, 153-8902 Tokyo, Japan.
Hum Mov Sci. 2006 Apr;25(2):181-91. doi: 10.1016/j.humov.2005.11.007. Epub 2006 Feb 3.
Bilateral deficit has been used to describe the phenomenon of a reduction in performance during synchronous bilateral movements when compared to the sum of identical unilateral movements. The study of bilateral deficit in humans under isometric, and to a lesser extent, dynamic conditions has shown bilateral decreases in force and muscle activation, and delayed reaction time. Results are equivocal, however, and biomechanical analyses of dynamic conditions, i.e., movements, are lacking. Our purpose was to determine, through an analysis of kinematic, kinetic, and electromyographic (EMG) data, whether or not bilateral deficit was present during a dynamic multi-joint movement under conditions where the external load was relatively equal for unilateral and bilateral efforts. Five male participants performed repeated unilateral and bilateral maximal horizontal leg press jumps under 100% (1BW) and 200% (2BW) relative body weight loads. Significant bilateral deficits in resultant ground reaction impulse of 27.7% and 13.0% were present in 1BW and 2BW, respectively. Maximum joint power at the hip exhibited significant deficits in both 1BW and 2BW of 35.6% and 25.1%, respectively. In both 1BW and 2BW conditions, ankle (15.5% and 11.5%), knee (10.9% and 5.7%), and hip (38.5% and 30.4%) work was significantly affected. Statistically significant EMG bilateral deficits were found in every muscle in both conditions except for rectus femoris during the 2BW trials. Bilateral deficit values ranged from 9.1% to 20.9% for 1BW, while deficits between 6.1% and 20.7% were found in 2BW. These results indicate that during dynamic leg press, bilateral deficit does exist, but that individual muscle activation levels and joint kinetics are not equally affected.
双侧赤字已被用于描述与相同单侧运动的总和相比，同步双侧运动时表现下降的现象。在等长条件下以及在较小程度上在动态条件下对人类双侧赤字的研究表明，力量和肌肉激活出现双侧下降，且反应时间延迟。然而，结果并不明确，并且缺乏对动态条件（即运动）的生物力学分析。我们的目的是通过分析运动学、动力学和肌电图（EMG）数据，确定在单侧和双侧用力时外部负荷相对相等的条件下，动态多关节运动期间是否存在双侧赤字。五名男性参与者在相对于体重100%（1BW）和200%（2BW）的负荷下进行重复的单侧和双侧最大水平腿部推举跳跃。在1BW和2BW时，合成地面反应冲量分别存在27.7%和13.0%的显著双侧赤字。髋部的最大关节功率在1BW和2BW时分别存在35.6%和25.1%的显著赤字。在1BW和2BW条件下，踝关节（15.5%和11.5%）、膝关节（10.9%和5.7%）和髋关节（38.5%和30.4%）的功均受到显著影响。在2BW试验期间，除股直肌外，两种条件下的每块肌肉均发现有统计学意义的EMG双侧赤字。1BW时双侧赤字值范围为9.1%至20.9%，而2BW时赤字范围为6.1%至20.7%。这些结果表明，在动态腿部推举过程中，双侧赤字确实存在，但各个肌肉的激活水平和关节动力学受到的影响并不相同。
