Lay Andrea N, Hass Chris J, Gregor Robert J
Bioengineering Program, School of Mechanical Engineering, Georgia Institute of Technology, GA, USA.
J Biomech. 2007;40(13):3050-5. doi: 10.1016/j.jbiomech.2007.02.004. Epub 2007 Apr 12.
The purpose of this study was to examine lower extremity kinetics and muscle activity during backward slope walking to clarify the relationship between joint moments and powers and muscle activity patterns observed in forward slope walking. Nine healthy volunteers walked backward on an instrumented ramp at three grades (-39% (-21 degrees ), 0% (level), +39% (+21 degrees )). EMG activity was recorded from major lower extremity muscles. Joint kinetics were obtained from kinematic and force platform data. The knee joint moment and power generation increased significantly during upslope walking; hip joint moment and power absorption increased significantly during downslope walking. When compared to data from forward slope walking, these backward walking data suggest that power requirements of a task dictate the muscle activity pattern needed to accomplish that movement. During downslope walking tasks, power absorption increased and changes in muscle activity patterns were directly related to the changes in the joint moment patterns. In contrast, during upslope walking tasks, power generation increased and changes in the muscle activity were related to the changes in the joint moments only at the 'primary' joint; at adjacent joints the changes in muscle activity were unrelated to the joint moment pattern. The 'paradoxical' changes in the muscle activity at the adjacent joints are possibly related to the activation of biarticular muscles required by the increased power generation at the primary joint. In total, these data suggest that changing power requirements at a joint impact the control of muscle activity at that and adjacent joints.
本研究的目的是检查下坡行走过程中的下肢动力学和肌肉活动，以阐明关节力矩和功率与上坡行走中观察到的肌肉活动模式之间的关系。九名健康志愿者在一个装有仪器的斜坡上以三个坡度（-39%（-21度）、0%（水平）、+39%（+21度））向后行走。记录了主要下肢肌肉的肌电图活动。关节动力学数据来自运动学和力平台数据。上坡行走时膝关节力矩和功率产生显著增加；下坡行走时髋关节力矩和功率吸收显著增加。与上坡行走数据相比，这些下坡行走数据表明，一项任务的功率需求决定了完成该运动所需的肌肉活动模式。在下坡行走任务中，功率吸收增加，肌肉活动模式的变化与关节力矩模式的变化直接相关。相比之下，在上坡行走任务中，功率产生增加，肌肉活动的变化仅与“主要”关节处的关节力矩变化有关；在相邻关节处，肌肉活动的变化与关节力矩模式无关。相邻关节处肌肉活动的“矛盾”变化可能与主要关节处功率产生增加所需的双关节肌肉的激活有关。总的来说，这些数据表明，关节处功率需求的变化会影响该关节及相邻关节处肌肉活动的控制。
