Division of Physical Therapy, Department of Allied Health Sciences, University of North Carolina at Chapel Hill, USA; Cleveland Clinic, Cleveland, OH, USA.
Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, USA; Teleflex Medical, Durham, NC, USA.
J Electromyogr Kinesiol. 2014 Feb;24(1):172-7. doi: 10.1016/j.jelekin.2013.10.006. Epub 2013 Oct 22.
It is believed that force feedback can modulate lower extremity extensor activity during gait. The purpose of this research was to determine the role of limb loading on knee extensor excitability during the late stance/early swing phase of gait in persons post-stroke. Ten subjects with chronic hemiparesis post-stroke participated in (1) seated isolated quadriceps reflex testing with ankle loads of 0-0.4Nm/kg and (2) gait analysis on a treadmill with 0%, 20% or 40% body weight support. Muscle reflex responses were recorded from vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) during seated testing. Knee kinematics and quadriceps activity during late stance/early swing phase of gait were compared across loading conditions. Although isolated loading of the ankle plantarflexors at 0.2Nm/kg reduced VM prolonged response (p=0.04), loading did not alter any other measure of quadriceps excitability (all p>0.08). During gait, the use of BWS did not influence knee kinematics (p=0.18) or muscle activity (all p>0.17) during late stance/early swing phase. This information suggests that load sensed at the ankle has minimal effect on the ipsilateral quadriceps of individuals post-stroke during late stance. It appears that adjusting limb loading during rehabilitation may not be an effective tool to address stiff-knee gait following stroke.
人们认为力反馈可以调节步态中下肢伸肌的活动。本研究的目的是确定肢体负荷在脑卒中后患者步态后期支撑/早期摆动阶段对膝关节伸肌兴奋性的作用。10 名慢性偏瘫脑卒中患者参与了（1）坐姿下的股四头肌反射测试，踝部负荷为 0-0.4Nm/kg；（2）在跑步机上进行步态分析，负荷分别为 0%、20%或 40%体重支撑。在坐姿测试中，从股外侧肌（VL）、股直肌（RF）和股中间肌（VM）记录肌肉反射反应。比较了不同负荷条件下步态后期支撑/早期摆动阶段的膝关节运动学和股四头肌活动。尽管在 0.2Nm/kg 时对踝关节跖屈肌进行单独加载会延长 VM 的反应时间（p=0.04），但加载不会改变股四头肌兴奋性的任何其他测量值（均 p>0.08）。在步态中，使用 BWS 不会影响膝关节运动学（p=0.18）或肌肉活动（均 p>0.17）在后期支撑/早期摆动阶段。这些信息表明，在后期支撑阶段，踝关节感知到的负荷对脑卒中后个体的同侧股四头肌影响很小。看来，在康复过程中调整肢体负荷可能不是解决脑卒中后僵硬膝关节步态的有效工具。
